Helveticosaurus zollingeri, one of those strange Triassic marine reptiles that no-one ever talks about, wrestling in a coastal swamp. Not everything about being a marine tetrapod takes place in the sea.

The fossil record is full of fascinating, relatively well-represented species that, on paper, seem like they should be widely known and featured in all sorts of palaeontological media, and yet in reality are almost entirely overlooked in popular literature, documentaries and games. Triassic marine reptiles are definitely among these animals. Many are distinctive, unusual and well-researched species that are just as interesting (if not more so) than many more familiar Triassic animals, and yet their popular coverage is frequently dire: even their Wikipedia pages are little more than footnotes.

In interests of trying to correct this injustice even a little, it's time to talk about a Triassic marine reptile with a criminally poor popular coverage/deserved interest ratio: Helveticosaurus zollingeri. Discovered in Middle Triassic rocks of Switzerland in 1933 and described some years later (Peyer 1955), this small-headed, long-armed marine reptile represents a unique anatomical experiment among aquatic tetrapods: a sort of lizard-seal thing with a skull from an '80s supernatural horror film. Its basic bauplan is well demonstrated thanks to a mostly complete and reasonably preserved holotype, missing only the end of the tail and some parts of the limbs. Alas, some especially informative aspects of its anatomy are poorly represented, including the skull, distal limbs and pelvis. Though all are present, they are disarticulated and difficult to interpret. Additional Helveticosaurus specimens are known (Kuhn-Schnyder 1974), but are not as well preserved or complete as the holotype and don't add much to our knowledge of this species (Rieppel 1989). Though attracting reasonable scientific interest in the last half century, much about its lifestyle and evolutionary relationships remain unexplored or contentious.

The Helveticosaurus zollingeri holotype, as illustrated by Kuhn-Schnyder (1974). Although a little jumbled, a good portion of the skeleton is preserved. It's unfortunate the skull is such a mess. Check out Wikipedia for a photo of the actual specimen.

Much of our modern take on this animal has been informed by Olivier Rieppel's 1989 paper on its anatomy and function, and the following overview is largely based on this assessment. Helveticosaurus was a small-headed creature with a short neck, long body and a tail of unknown length. The preserved portion of the tail comprises large, well developed vertebrae and it doesn't seem unreasonable to assume it was much longer when complete. If we had a more secure idea of the phylogenetic position of Helveticosaurus we might take a stab at estimating the tail length, but this doesn't seem possible at the moment.

Tail proportions are not the only issue confusing predictions of the overall body length of this animal. When preparing this post I found that the total length estimates of Helveticosaurus provided in modern papers are at odds with measurements of skeletal elements within the holotype, to the effect that we might be significantly underestimating its overall size. Recent papers give a total predicted length of c. 2 m for the holotype animal (e.g. Rieppel 1989; Cheng et al. 2014), while also reporting that the lower jaw of the same specimen is 250 mm long, and the humerus as 205 mm (Rieppel 1989; Cheng et al. 2014). Even just eyeballing images of the holotype suggests some sort of miscalculation here: there's no way the entire animal - including the missing tail - is just 10 times the length of these bones. Using a line drawing of the holotype from Khun-Schnyder (1974) and the reported mandible and humerus measurements, I found that 2.1 - 2.8 m better describes the length of the preserved skeleton (see calculations in the image below, note that the reported 45 mm difference between the humerus and mandible length is not obvious in the drawing I used, resulting in two different body length estimates. Scaling from photos or illustrations is not a substitute for measuring actual specimens). This is back-of-the-envelope stuff, but it's enough to convince me that Helveticosaurus wasn't a 2 m long animal. I wonder if the figures reported by Khun-Schnyder (1974) are more plausible: he reported a 2.5 m length for the preserved holotype skeleton, and an estimated total length of 3.6 m. That would add another metre onto the holotype, which seems quite plausible - maybe even conservative - to me.

Just how big was Helveticosaurus? It's hard to say without a complete specimen, but the individual represented by the holotype skeleton clearly exceeded the oft-cited 2 m body length. Perhaps other published estimates of 3.6 m are more reasonable?

One of the most interesting features of Helveticosaurus is its short, c. 25 cm long skull. Alas, the best Helveticosaurus skull remains we have look as if they were hit by a truck before fossilisation: scattered, broken, and with many unidentifiable parts (Rieppel 1989). Enough is known to allow for a tentative reconstruction but a confident picture of the face of Helveticosaurus awaits better preserved material. The front of the upper jaw was abbreviated, blunt and tall, creating a skull profile that might have been somewhat box-like in lateral aspect. The orbital and temporal regions are poorly known, but they seem to hint at the presence of an upper and lower temporal fenestrae and a large eye socket. A number of oversize conical teeth line each jaw. The exact number of teeth is unknown, but a notable feature is the large 'canine' in the upper jaw. Neither the size of the temporal region or the lower jaw (the latter being one of the best preserved cranial elements) imply an especially large set of jaw muscles, though the mandible has an expanded retroarticular process - a prong of bone at the back of the jaw associated with opening the mouth. This likely has implications for the feeding style of Helveticosaurus, although I'm unaware of any studies into its function. The aberrant size of the Helveticosaurus skull is peculiar for a marine reptile lacking a long neck, and perhaps only challenged in proportion by the Triassic marine vacuum cleaner Atopodentatus (Cheng et al. 2014). Distinct anatomy make it clear that these animals were very different ecologically however, and it's possible that their diminutive skulls reflect very different adaptive regimes.

Tentative Helveticosaurus skull reconstruction, from Rieppel (1989). The jaws remain the best known elements, and some question exists over the arrangement of the rest of the skull. Scale bar represents 50 mm.

The body of Helveticosaurus is similar, at least superficially, to many other Triassic marine reptiles, especially early sauropterygians. It's torso was long, with well-developed and high-spined vertebrae, stout ribs and an extensive set of gastralia (belly ribs). Differentiation between the vertebral spines at the front and back of the body hint at some functional distinction, perhaps related to larger muscles associated with the shoulder region (Rieppel 1989). As is assumed for plesiosaurs, the combination of stout ribs and gastralia likely reduced the flexibility of the torso and may have improved swimming efficiency. The tail, so much as it is known, bears the same high neural spines as the trunk vertebrae, as well as caudal ribs. These features indicate it was likely well-muscled for use in sculling propulsion, although the chevrons are not particularly large. Assuming these anchored the caudofemoralis muscle, as they do in most reptiles, I wonder if this indicates diminished musculature associated with hindlimb retraction.

After the peculiar head, the forelimbs of Helveticosaurus are perhaps its most unusual feature. They anchored to an atypically well-developed pectoral girdle which - unlike most marine reptiles - has a long, robust scapula. Marine reptile shoulder blades are often extremely reduced, little more than bony nubbins that create a shoulder joint. But here, the scapulae are long enough to create a deep, U-shaped shoulder girdle that would not look out of place on a terrestrial animal (Rieppel 1989). The forelimb itself is proportionally elongate, both with respect to the body and in comparison to the hindlimb. It's exact length remains uncertain because the bones of the hand are scattered, but the major limb bones are each 10% longer than their counterparts in the hindlimb. The humerus in particular is very long for a marine reptile, and maintains hallmarks of functionality beyond just being the top of an stiffened flipper (Rieppel 1989). The fingers are hyperphalangic (i.e. they have an enhanced number of finger bones) in a fashion typical of marine tetrapods, and - in contrast to several Helveticosaurus palaeoartistic reconstructions (all five of them that exist) - they lack claws. The arrangement of the fingers requires some reconstruction but their slender bones and arrangement in the holotype implies more of a broad, rounded paddle than a narrow ichthyosaur or plesiosaur-like flipper.

Helveticosaurus forelimb, as illustrated by Rieppel (1989). Some ribs and gastralia have been removed for clarity. Note the elongate scapulae and long forelimb elements - this is not a typical marine reptile arm. Scale bar represents 100 mm.

The hindlimb shares some general characteristics with the forelimb - relatively elongate limb bones for a marine form, hyperphalangy, spreading, unclawed digits - but is shorter, noticeably more gracile and probably more cartilaginous than the forelimb. The pelvis is poorly known, but it also appears to have been at least partly cartilaginous, the joints of the pelvic bones being insufficient to contact one another around the hip joint without some additional skeletal material (Rieppel 1989). These features imply that the hindlimb was structurally weaker than the forelimb.

How might this mix of anatomies have functioned? A qualified assessment by Rieppel (1989) makes some sensible interpretations of Helveticosaurus locomotion. On the whole, the animal is mostly adapted for life in water, with aquatic adaptations being especially obvious on the limbs, pelvis and tail. Although the tail is missing, its robust, high-spined and complex vertebrae are consistent with features of sculling animals and we might envisage Helveticosaurus propelling itself with powerful motions of its tail when swimming, akin to marine iguanas or crocodylians. The weak pelvis and hindlimb indicate the rear limbs contributed less to propulsion. Rieppel proposes that, like swimming lizards, they may have been pulled against the body when swimming save for the occasional action to help with steering or thrust. The forelimbs were evidently strong and likely useful in swimming, though the configuration of the shoulder girdle does not imply any rigid kinematics for underwater flight in the manner of a penguin or turtle. They might have functioned more like the foreflippers of otariid seals (the eared seal group: sealions, fur seals etc.) in providing some thrust, but also playing important roles in steering and breaking (Rieppel 1989). While the shoulder girdle does not seem optimised for powerful downstrokes, the large size of the arm, and implied articulation of at least some parts of the limb (see below), suggest it was a dynamic steering aid. Helveticosaurus may have been quite an agile swimmer.

But where Helvetiosaurus becomes especially interesting is out of the water. Even in the Middle Triassic many marine reptiles had wholly committed themselves to aquatic lifestyles, but Helveticosaurus appears to have remained some terrestrial capabilities. Why it did this remains uncertain: did it still lay eggs? Did it have a complex life history involving both land and sea phases? Did it live in settings where periodic escapes from the sea were advantageous? We don't have insights into any of this yet, but we can predict how Helveticosaurus might have moved around on land. Supporting limbs during terrestrial gaits is not simply a matter of having strong limb bones, it's also necessary to have a robust and stable limb girdle. For shoulders, this requires support and control exerted by muscles attached to the torso and neck, as well as having a big enough scapula for these to act on. The robust shoulder girdle of Helveticosaurus seems to meet these criteria. It not only provides space for the necessary muscle to support and move the forelimb on land but also - with particular reference to the relatively big scapula - is sufficiently developed to brace the shoulder against the body skeleton (Rieppel 1989). The length and robustness of the forelimb is also notable, as are the retention of humeral features associated with flexing the lower limb. Marine reptile limbs are often immobile south of the shoulder or hip, and readers with good memories might recall that this makes terrestrial locomotion difficult. The articulations of the Helveticosaurus limb are not well preserved - they seem to have been highly cartilaginous - so we don't know the full extent of its forelimb mobility, but muscle attachment scars hint at abilities to flex the wrist and fingers (Rieppel 1989). Any flexible jointing would enhance its terrestrial potential, so this is another tick in the box for relatively proficient land locomotion. The hindlimb, in being less developed and more cartilaginous, probably contributed little to terrestrial locomotion. Helveticosaurus may have therefore crawled and flopped around more like a seal than a lizard, using its arms to drag and push itself around, maybe occassionally assisted by its legs and thrashing motions of the tail to propel itself faster. It must have been pretty neat to see a reptile move like this: a sort of creeping, lolopping reptile-mermaid topped off with the face of the Engineer from Hellraiser.

When Helveticosaurus collide. In the image illustrating this article, I've assumed that the terrestrial capabilities of Helveticosaurus were sufficient to bring them into terrestrial coastal habitats, perhaps for mating, nesting or some other reason. We have no evidence of this happening, but analogous behaviours are seen today in turtles and seals, some of which travel kilometres inland despite their limited terrestrial abilities. Maybe some Mesozoic marine reptiles did the same.

We can't go this far into discussion of Helveticosaurus without questioning its ecology. I'm not aware of any analyses that address this issue, so this paragraph is shot from the hip based on what others have said about its functional morphology and a basic form-function reading of Helveticosaurus anatomy - take it with an appropriate pinch of salt. As already noted, the skull of Helveticosaurus is too poorly preserved to say much about specifics of foraging, but its long, slender teeth clearly betray a predatory lifestyle. Worn tooth tips indicate that it did not eat entirely soft, fleshy prey, but the teeth are not robust enough to suggest a tough diet. I'm aware that a similar suite of dental features occur in pterosaurs that are assumed to small fish, squid and other diminutive swimming creatures (Ősi 2010), and I wonder if a similar diet might apply here. The skull of Helveticosaurus is also too small to suggest it routinely ate large prey, though I guess scavenging carcasses is difficult to rule out. The enlarged retroarticular process is of interest because such features are often seen in suction feeders - aquatic animals which rapidly open their mouths to suck up prey within a pressure gradient. Short faces often characterise suction feeders too, but we need knowledge of other anatomies - such as the bones of the throat - to reliably infer such foraging strategies (Motani et al. 2014). We also have to acknowledge that a short jaw and specifics of the posterior mandible can be related to other functions. A small head capable of fitting between rocks and other obstacles would be useful if Helveticosaurus sought benthic or demersal prey, for instance. The combination of a swimming tail and large limbs may have made Helveticosaurus relatively agile, a useful trait when chasing small prey. In all, I wonder if the seal analogy applied to some aspects of Helveticosaurus anatomy and locomotion might extend to its lifestyle. It would be great to see this looked into with a dedicated study.

Bringing this post back to firmer scientific ground, it's finally time to ask: just what the heck is Helveticosaurus? Initially interpreted as a placodont (Peyer 1955), Helveticosaurus has since jumped all over the reptile tree as different teams use different approaches to resolve its placement. There are probably several reasons for our inability to pin down the evolutionary home of Helveticosaurus. Firstly, the anatomy of Helveticosaurus confuses character distribution in phylogenetic trees, it having features of enough groups to scramble easy reading of homologies and convergences (Ezcurra et al. 2014). This makes Helveticosaurus very sensitive to taxon and character choices used in our evolutionary calculations, and prone to shifting in position dramatically from one cladogram to the next (e.g. Chen et al. 2014). Helveticosaurus is far from the only marine reptile to present such a problem, and there are debates among researchers about how to deal with what some regard as a problematic amount of convergence between aquatic Mesozoic reptiles (see, for recent takes, Chen et al. 2014 vs. Scheyer et al. 2017). A third issue concerns the ongoing controversy over the origins of marine reptiles generally. The relationships of even well-supported groups like ichthyosauromorphs, turtles and sauropterygians to other reptiles remain contested, and these clades have major 'pull' in phylogenies when they move about, hauling possible relatives like Helveticosaurus around as tree topologies change.

We don't know of any species quite like Helveticosaurus, but the Triassic diapsid Eusaurosphargis dalsassoi - here represented by an excellent fossil of a juvenile skeleton - has been recovered as a near relative in several recent analyses. Intriguingly, it also seems well adapted for terrestrial locomotion, implying that such abilities may have been common to their branch of marine reptile evolution. Image from Scheyer et al. (2017).

Perhaps for this reason, it's not uncommon to see many authors sidestepping classifying Helveticosaurus altogether, instead simply labelling it an 'enigmatic diapsid' and moving on. But others have tackled the issue more head on and, while it would be premature to say we know what Helveticosaurus is, some clarity is emerging about which branch of reptile evolution it belongs to (even if the position of that branch is a more open question). The placodont affinity for Helveticosaurus has been questioned on grounds of very limited shared anatomies (Sues 1987; Rieppel 1989) and this identification has not been supported in recent analyses. Other ideas - a tentative interpretation as some sort of archosauromorph (Rieppel 1989; Naish 2004) or a near relative of lepidosaurs (Chen et al. 2014) - have also not found much traction. But a large number of authors have recovered Helveticosaurus as a close relative of Sauropterygia (Müller 2004; Bickelmann et al. 2009; Li et al. 2011, 2014; Neenan et al. 2013; Chen et al. 2014; Scheyer et al. 2017), and it's looking like this is the best horse to back concerning the phylogenetic position of this historically enigmatic animal.

Alas, this is not the neat end of the story we might think it is, as the origins of Sauropterygia itself remain poorly understood. In at least some analyses Helveticosaurus and Sauropterygia is part of a marine reptile 'superclade', a huge, unnamed group containing ichthyosaurs, sauropterygians and a number of Triassic lineages that have long struggled to find homes. Another Swiss Triassic reptile, the possibly mostly terrestrial Eusaurosphargis dalsassoi (above), has been postulated as a close relative of Helveticosaurus several times (e.g. Scheyer et al. 2017). Sauropterygians are deeply nested in this 'superclade' and the position of the terrestrially-enabled Helveticosaurus and Eusaurosphargis is interesting with respect to the evolution of aquatic lifestyles in Triassic marine reptiles. Given that more rootward lineages in the 'superclade' are entirely aquatic forms, might genera like Helveticosaurus and Eusaurosphargis represent animals that returned to land from swimming ancestors, or are they representatives of a more basic semiaquatic ancestral bauplan that remains underrepresented in other lineages? At the risk of ending on an old palaeontological cliche, we need more specimens, more data and more investigations to answer these questions.

It turns out that marine reptiles are a pretty fun group, I think you'll be seeing more art and reading more about them here in the coming months. If all goes to plan, we'll be walking (or not) with plesiosaurs and meeting some giant ichthyosaurs before too long.

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References

• Bickelmann, C., Müller, J., & Reisz, R. R. (2009). The enigmatic diapsid Acerosodontosaurus piveteaui (Reptilia: Neodiapsida) from the Upper Permian of Madagascar and the paraphyly of “younginiform” reptiles. Canadian Journal of Earth Sciences, 46(9), 651-661.
• Chen, X. H., Motani, R., Cheng, L., Jiang, D. Y., & Rieppel, O. (2014). The enigmatic marine reptile Nanchangosaurus from the Lower Triassic of Hubei, China and the phylogenetic affinities of Hupehsuchia. PLoS One, 9(7), e102361.
• Cheng, L., Chen, X. H., Shang, Q. H., & Wu, X. C. (2014). A new marine reptile from the Triassic of China, with a highly specialized feeding adaptation. Naturwissenschaften, 101(3), 251-259.
• Ezcurra, M. D., Scheyer, T. M., & Butler, R. J. (2014). The origin and early evolution of Sauria: reassessing the Permian saurian fossil record and the timing of the crocodile-lizard divergence. PLoS One, 9(2), e89165.
• Kuhn-Schnyder, E. (1974). Die Triasfauna der Tessiner Kalkalpen. Neues Jahrbuch der Naturforschenden Gesellschaft in Zürich, 176, 1–119
• Li, C., Rieppel, O., Wu, X. C., Zhao, L. J., & Wang, L. T. (2011). A new Triassic marine reptile from southwestern China. Journal of Vertebrate Paleontology, 31(2), 303-312.
• Li, C., Jiang, D. Y., Cheng, L., Wu, X. C., & Rieppel, O. (2014). A new species of Largocephalosaurus (Diapsida: Saurosphargidae), with implications for the morphological diversity and phylogeny of the group. Geological Magazine, 151(1), 100-120.
• Motani, R., Ji, C., Tomita, T., Kelley, N., Maxwell, E., Jiang, D. Y., & Sander, P. M. (2013). Absence of suction feeding ichthyosaurs and its implications for Triassic mesopelagic paleoecology. PLoS One, 8(12), e66075.
• Müller, J. (2004). The relationships among diapsid reptiles and the influence of taxon selection. In G. Arratia, M. V. H. Wilson & R. Cloutier (eds.): Recent advances in the origin and early radiation of vertebrates, 379-408.
• Naish, D. (2004). Fossils explained 48: Placodonts. Geology Today, 20(4), 153-158.
• Neenan, J. M., Klein, N., & Scheyer, T. M. (2013). European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia. Nature Communications, 4, 1621.
• Ősi, A. (2011). Feeding‐related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet. Lethaia, 44(2), 136-152.
• Peyer, R. (1955). Die Triasfauna der Tessiner Kalkalpen. XVIII. Helveticosaurus zollingeri, n. g. n. sp. Schweizerische Palaeontologische Abhandlungen, 72, 1–50.
• Rieppel, O. (1989). Helveticosaurus zollingeri Peyer (Reptilia, Diapsida) skeletal paedomorphosis, functional anatomy and systematic affinities. Palaeontographica Abteilung A, 123-152.
• Scheyer, T. M., Neenan, J. M., Bodogan, T., Furrer, H., Obrist, C., & Plamondon, M. (2017). A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny. Scientific reports, 7(1), 4406.
• Sues, H. D. (1987). On the skull of Placodus gigas and the relationships of the Placodontia. Journal of Vertebrate Paleontology, 7(2), 138-144.

How the heavy hitters covered Hone et al. 2018: a short, open-access and easy-to-read paper about a shark tooth preserved with Pteranodon. The Sun gets bonus stupid points for making their own graphic.

Sigh.

Major news outlets have been reporting this week that a new study evidences prehistoric sharks predating pterosaurs by leaping from the water to snatch them in mid-air. It would be an awesome discovery, if it were true. In reality, these headlines are nothing but a construct by journalists based on a misread palaeoart image, ignorance of some basic facts of animal biology, and lazy science reporting. I'm particularly angry because the study being misreported, and the art being misread, stems from a paper that I recently published with with my friends and colleagues Dave Hone and Mike Habib (Hone et al. 2018). The paper is in PeerJ, and is thus open-access. Anyone - including our dear media - can fact check what we have to say without hitting a paywall.

The nature of modern news is that stories can spread like wildfire, and it's effectively impossible to correct major gaffes once a story gains momentum. With that in mind, the best I can do is outline here what our new paper actually says, what our artwork actually shows, and hope that readers link to this post wherever they see this ridiculous press story being shared. It must be said that a number our outlets are reporting the story more accurately, but enough have mangled our findings that I feel I need to do something. I genuinely care about the accurate conveyance of science, and I've found this distortion of our work and my painting very distressing.

What our paper actually says

OK, first up: a summary of our paper. Mike, Dave and I have documented a series of neck vertebrae from the famous Late Cretaceous pterosaur Pteranodon associated with the tooth of a lamniform shark, Cretoxyrhina mantelli. The vertebrae and their teeth were found in 1965 but our records about their discovery are confused and we don't know whether they were part of a larger discovery of bones, or just a few isolated remains. There are hints that they may have been part of a more impressive skeleton, but it's pretty hard to tell. In any case, today this string of vertebrae is on display at the Los Angeles County Museum as part of a composite skeleton.

Vertebrae are not diagnostic for different Pteranodon species so we refrain from identifying the pterosaur beyond Pteranodon sp. The specimen was found in Niobrara Formation rocks that traditionally yield P. longiceps however, and this is probably the likely species identity- we just can't verify it*. The identification of the shark is better constrained as the tooth is a perfect match for C. mantelli. Indeed, we can even tell which part of the mouth it came from thanks to Cretoxyrhina mantelli being exceptionally well known: even complete skulls and skeletons have been found. This allows us to roughly gauge the size of the Cretoxyrhina as c. 2.5 m long, which makes it a small individual compared to the 6-7 m specimens known from other remains. Our Pteranodon was on the small size as well at c. 5 m across the wings. This is within the upper size range of Pteranodon fossils, but still 1-2 m off the full wingspread of this species.

*If anyone's wondering, yes, we follow the traditional Bennettian concept of Pteranodon taxonomy. It was actually writing the manuscript for this paper that prompted my blog post on Pteranodon taxonomy.

Pteranodon sp. specimen LACM 50926 as mounted as part of a composite skeleton in the Los Angeles County Museum, and in more detail with their hitchhiking Cretoxyrhina mantelli tooth (arrowed). Scale bar is 50 mm. From Hone et al. 2018.

The Cretoxyrhina tooth does not actually penetrate the pterosaur bone, but is wedged beneath a vertebral process in a complex, intimate manner. We assume this evidences the shark biting into the pterosaur neck and shedding a tooth into its soft-tissues. An alternative - that the specimens became associated through actions of currents or storms - is less plausible given the strange position of the tooth, its tightness to the specimen, as well as the gentle, low-energy marine conditions of the Niobrara Formation.

But what sort of circumstances brought these animals together? It's here that our questions go beyond what the fossils can tell us. There's only so much a single tooth and string of vertebrae can objectively reveal about an ancient animal interaction, and we conclude that either a predatory and scavenging act could have produced the association - there's just no way to tell. While a scavenging story explains itself (short version: pterosaur dies over water; shark gets a meal), we explored how a predatory scenario may have played out given the known fish-eating habits of Pteranodon and hypotheses that this pterosaur regularly dived or swam to catch its prey (e.g. Bennett 2001; Hone and Henderson 2014; Witton 2013, 2018). Swimming pterosaurs are a new idea to many but substantiated by several lines of evidence, including swimming tracks, modelling of their aquatic launch strategy, and studies of their floating capability (Lockley et al. 2003; Habib and Cunningham 2010; Hone and Henderson 2014; see this blog post for a summary). We propose that if Pteranodon was a regular swimmer it would be vulnerable to sharks and other large predators, and its flight muscles would surely be a decent meal for many carnivores. Pterosaurs were probably pretty sinewy across their limbs, but there'd be some sizeable steaks to carve from their shoulders and chests. As big, powerful predators, it seems entirely plausible that even a half-size Cretoxyrhina would be capable of subduing a large Pteranodon, assuming they could catch one.

And that is as far as we go in our paper - it's pretty conservative stuff. You can read another summary of the paper at Dave Hone's Archosaur Musings.

The illustration

Rocket shark eats flying pterosaur? No. Artwork of a small Cretoxyrhina mantelli attacking a group of floating Pteranondon longiceps, erupting from the sea with one in its jaws. Note the other swimming pterosaurs in this picture - it's almost like pterosaurs weren't always flying, or something. From Hone et al. 2018.

Mike, Dave and I are palaeoart fans and we all - perhaps myself especially - enjoy well-illustrated papers, so we decided to include a reconstruction of Cretoxyrhina vs. Pteranodon in our paper (above). Having recently drawn an image of Pteranodon being hounded by another Cretaceous shark, Squalicorax, at the water surface, I wanted to do something different with this illustration and decided on a more exciting breaching scene: a shark leaping from the water with a Pteranodon in its mouth. Anyone who's watched even a few wildlife documentaries will know this behaviour is far from speculative: it's a widely-filmed, photographed and documented behaviour of South African white sharks (see Planet Earth excerpt from BBC Earth, below). These sharks strike floating prey with such speed that they leap entirely from the water. It's very dramatic, very awesome and seemed like great inspiration for a palaeoartwork. And sure, we have no idea that Cretoxyrhina did this, but a breaching attack is no more or less speculative than any other means of depicting a shark tooth lodging in a Pteranodon neck. I won't bore you with some additional practical factors that influenced the composition (in short, this image is being featured in an upcoming book where I have some firm ideas about visual narrative, and this strongly influenced choices of posture and colour).


A number of swimming and water-launching pterosaurs were added in the background of the image to make it clear that the Pteranodon was caught from a floating position. In my mind, the image shows a flock of pterosaurs busying themselves in the sea before Cretoxyrhina crashes their party - you can invent your own reasons for all the Pteranodon milling about. Maybe they're foraging, maybe they're congregating for another reason - it doesn't matter too much, what matters is that the sea has six or so Pteranodon either floating or launching from the water. Also note that water is shedding from the main pterosaur's wings, as if it's just left the water along with the shark. I carefully referenced how much water should be flying about using footage and photos of breaching sharks around the peak of their arcs: we often overdo water dynamics in palaeoart, and I was keen to make this image grounded in spite of its spectacular action.

So what's gone wrong?

What we've ended up with, then, is a pretty simple, conservative paper with an illustration that is pretty bleeding edge in terms of pterosaur science (flying reptiles as swimmers) and radical in terms of shark behaviour (breaching). But the two are entirely compatible with one another and the image is appropriately grounded in zoology and palaeontology. It looks extreme, but it's not ridiculous compared to what happens in modern natural history.

Unfortunately, this broader face of our project has been neglected in the media. Instead, our artwork - or rather a knee-jerk, lunkhead interpretation of it - has become the media story and we now have 'science-endorsed' headlines stating that sharks shot out of the water to grab pterosaurs (or even 'flying dinosaurs' in several articles) when they soared overhead. As I've outlined here, this is entirely false, and not representative of our ideas at all. Any hope that our paper could be used to broadly communicate some cool ideas about pterosaur ecology, the role of sharks as important predators throughout the Mesozoic, or even the simple fact that pterosaurs could likely swim has been lost behind ridiculous headlines based on erroneous readings of my picture.

So that's basically that - this is essentially a tale of how quickly false information can spread when it's attached to a pretty image, and why we shouldn't believe everything we read. Perhaps there's a lesson here in the power of imagery, and I am certainly now wondering if I erred in my reconstruction being too complex (to my defence, I did not contribute to the PR campaign for this and did not get the opportunity to sign off on an appropriate description for the picture). Perhaps we're looking at the reality of naive audiences assuming that anything to do with sharks or prehistoric creatures must automatically be the most awesome, badass thing. Maybe I erred in my assumption that people would be familiar with the basics of breaching shark behaviour.

But what this hits home hardest for me is the reality of science reporting in our digital, content-fuelled age. Anyone who led with the stupid shark vs. flying pterosaur headline went nowhere near our actual paper to check what we said, even though it was literally just a link click away. They simply parroted one another to make sure their outlets have the same stories as everyone else. Only a few thought to double check what our conclusions were, and I find that distressing. Remember folks, these are the same guys who're reporting news about far more important things than pterosaurs: vaccinations, climate change, health and environmental issues, and so on: these pterosaur-devouring rocket sharks are stark reminders of how they work. If you've seen accurately reported examples of this story (and they do exist) then add those news services to your bookmarks: they are rare examples of media outlets that aren't jumping our shark.

If understanding pterosaur ecology through fossil associations is of interest, be sure to check out this series of three blog posts: part 1, part 2, and part 3.

Enjoy monthly insights into palaeoart, fossil animal biology and occasional reviews of palaeo media? Support this blog for $1 a month and get free stuff!

This blog is sponsored through Patreon, the site where you can help online content creators make a living. If you enjoy my content, please consider donating $1 a month to help fund my work. $1 might seem a meaningless amount, but if every reader pitched that amount I could work on these articles and their artwork full time. In return, you'll get access to my exclusive Patreon content: regular updates on research papers, books and paintings, including numerous advance previews of two palaeoart-heavy books (one of which is the first ever comprehensive guide to palaeoart processes). Plus, you get free stuff - prints, high quality images for printing, books, competitions - as my way of thanking you for your support. As always, huge thanks to everyone who already sponsors my work!

References

• Bennett, S. C. (2001). The Osteology and Functional Morphology of the Late Cretaceous Pterosaur Pteranodon Part II. Size and Functional Morphology. Palaeontographica Abteilung A, 113-153.
• Habib, M. B., & Cunningham, J. (2010). Capacity for water launch in Anhanguera and Quetzalcoatlus. Acta Geoscientica Sinica, 31, 24-25.
• Hone, D. W., & Henderson, D. M. (2014). The posture of floating pterosaurs: ecological implications for inhabiting marine and freshwater habitats. Palaeogeography, Palaeoclimatology, Palaeoecology, 394, 89-98.
• Hone, D. W., Witton, M. P., & Habib, M. B. (2018). Evidence for the Cretaceous shark Cretoxyrhina mantelli feeding on the pterosaur Pteranodon from the Niobrara Formation. PeerJ, 6, e6031.
• Lockley, M. G., & Wright, J. L. (2003). Pterosaur swim tracks and other ichnological evidence of behaviour and ecology. Geological Society, London, Special Publications, 217(1), 297-313.
• Witton, M. P. (2013). Pterosaurs: natural history, evolution, anatomy. Princeton University Press.
• Witton, M. P. (2018). Pterosaurs in Mesozoic food webs: a review of fossil evidence. Geological Society, London, Special Publications, 455(1), 7-23.

Until comparatively recently it was not uncommon to see depictions of plesiosaurians* on rocks and beaches as if they had hauled themselves from the sea like breeding sea turtles or basking pinnipeds. Such restorations have a long history. Some of the earliest marine reptile palaeoart shows plesiosaurians on beaches or very shallow water, and we've even seen land-based plesiosaurians in feature films and documentaries, including notable sequences in When Dinosaurs Roamed the Earth(1969) and Walking with Dinosaurs (1999, below).

*Why 'plesiosaurians' rather than 'plesiosaurs'? Though a common vernacular, the term 'plesiosaurs' is potentially confusing as it could either refer to a number of marine reptile clades (e.g. plesiosauroids, plesiosaurids) or body plans (plesiosauromorphs). 'Plesiosauria' has a less ambiguous meaning as it specifically refers to the clade encompassing rhomaleosaurids, pliosauroids and plesiosauroids, so it might be a preferable catch-all term this marine reptile clade.

Today, it's much rarer to see plesiosaurians depicted outside of the aquatic realm. For... reasons, I'm restoring a number of marine reptiles at the moment, so I've been wondering if it would be acceptable to revive artwork of these creatures on rocky shores, beaches and other coastlines, if only to bring some variation to my marine scenes. As usual, this inquiry began with a literature crawl. Because 19th century palaeoart suggests palaeontologists once imagined these animals as routinely emerging from the waves, I expected marine reptile papers to be full of discussion about the terrestrial prospects of plesiosaurians, perhaps with an in-depth analysis of the concept bringing an end to the artistic tradition of depicting them on land. The transition from imagining plesiosaurians as semi-aquatic to fully aquatic seems to have happened organically, however: if there's a watershed paper or significant debate behind this, I've missed it. Richard Ellis' 2003 book Sea Dragons - perhaps the closest thing we have to an all-encompassing introductory review of marine reptiles - seems to confirm my independent findings, portraying plesiosaur terrestrial abilities as highly doubtful, but also a question without a firm answer in scientific literature.


The idea of plesiosaurians leaving water has been strongly tied to historic uncertainty about their reproductive habits. It stands to reason that, if plesiosaurians laid eggs, they must have somehow dragged their way out of the sea to construct their nests (Taylor 1981, 1986). The notion that plesiosaurians could have given birth to live young is pretty old (e.g. Seeley 1896) but scant evidence of their reproductive strategies prevented dismissal of land-based nesting habits until relatively recently. We now have evidence of live birth in plesiosaurian relatives (nothosauroids, Sander 1988; Renesto et al. 2003; Cheng et al. 2004) as well as a true plesiosaurian (a polycotylid, O'Keefe and Chiappe 2011), and so we needn't imagine plesiosaurians hauling out onto beaches to lay eggs, turtle-style.

But I'm going to keep pulling at this thread. While their capacity to give birth to live offspring eliminates the behavioural necessity for leaving water, it does not, in itself, demonstrate that plesiosaurian anatomy was functionally incapable of land-based locomotion, or that they did not leave the sea to find refuge or seize prey - orca style - from shorelines. After all, viviparity does not mean that seals, sea otters or even manatees have committed to a fully aquatic life (a voluntarily beached manatee deserves a citation - see Motani et al. 2015). Is there a cogent functional argument for why plesiosaurians might struggle out of water that will let me (and others) escape painting nothing but blue and green pictures?

How plesiosaurians might have moved on land

Our discussion will be aided by first outlining what we might realistically expect of a walking or crawling plesiosaurian. No one, for instance, predicts that plesiosaurians could stride around like sea lions or the plesiosaur in When Dinosaurs Roamed the Earth. Their flipper skeletons were essentially inflexible so they were incapable of being articulated into a walking limb. This precludes walking on their hands and feet in the way that eared seals can. They were also likely incapable of bouncing along in the manner of true seals, where the flexibility of the spine is used to 'hump' their way forward while powerful, gripping claws pull and steer them around. Plesiosaurian bodies were pretty rigid - their robust gastralia and ribs are sometimes superficially compared to turtle shells - and likely incapable of the twisting and bending necessary to bounce their way over shorelines. And in lacking claws, the only contribution their flippers could make to crawling would be crude pushing and lifting actions.

True seals, such as the grey seal (Halichoerus grypus), are far less terrestrially proficient than the eared seals (sea lions, fur seals etc.) and have to bounce or drag themselves around when ashore. Large claws on their flippers help in this activity (and are also useful for scratching). Grey seal cow photo by Georgia Witton-Maclean.

If plesiosaurians could leave the water at all, we have to imagine something more akin to turtle locomotion: using their flippers to push and pull themselves along while lying on their bellies. Their weight and a likely inability to clear their bodies entirely from the ground predicts that much of their energy would go into overcoming drag incurred by their wide bodies and tails. Terrestrial plesiosaurians would need to make full use of their powerful flipper downstroke muscles (soundly evidenced by the enormous muscles of their chest and the underside of their hips; see Carpenter et al. 2010; Araújo and Correia 2015) to lift their bodies and propel themselves forward. The exact motion of their flippers remains controversial, but is likely to have been a wingbeat-like action (Taylor 1986; Carpenter et al. 2010; Liu et al. 2015; Muscutt et al. 2017) that may have been enough to shove plesiosaurians over shorelines. The picture we're building here is of a slow and laborious means of locomotion. If plesiosaurians did intentionally leave water, they almost certainly visited locations inaccessible to terrestrial predators.

Polycotylid Dolichorhynchops bonneri demonstrating a fairly typical plesiosaurian torso and flipper construction. At face value, the retention of four limbs and stout limb girdles looks like terrestrial locomotion shouldn't be too hard for these guys - they certainly look more terrestrially capable than many other marine tetrapods. From Carpenter et al. (2010). Scale bar is 1 m.

I also think we should rule out raw body size as a compelling reason to doubt land-based locomotion in plesiosaurians. There's no reason to regard plesiosaurians as atypically heavy compared to other marine animals (Everhart 2000, Henderson 2006) and, indeed, their general lack of pachyostosic skeletons might make them lightweight compared to some other aquatic tetrapods (e.g. Street and O'Keefe 2010). Many species were probably within the mass ranges of living species known to transition between land and sea. The known maximum limit for this lifestyle is set by bull elephant seals which, according to Wikipedia, reach 3,000 - 4,000 kg. We don't have many plesiosaurian mass estimates to compare this figure to, but a few noteworthy values are Everhart's (2000) predicted mass of 2.8 tonnes for a 9 m long plesiosauroid, and Henderson's (2006) 217 kg 3 m Cryptocleidus. Truly giant plesiosaurians - 10 and 11 m long individuals - are beyond the masses of big elephant seals (Henderson 2006), but this still leaves plenty of small and mid-sized species at or below the mass threshold of marine species that we know can venture onto land, assuming they have the right adaptations. For me, our question is most appropriately addressed through assessment of anatomy and functional morphology, not a priori judgements about size.

Scrutinising the model

The bar we've set for plesiosaurian terrestrial locomotion is thus pretty low: even if they can only shamble up a beach we could consider our conditions met. But how feasible is even this laborious means of getting around on land? To cut to the chase: not very. There are multiple aspects of plesiosaurian anatomy that probably precluded even very basic terrestrial capabilities.

Plesiosaurian flippers, for instance, seem poorly suited for use on coastal substrates. Semi-aquatic species such as turtles, seals and terrestrially-roaming fish have a degree of jointing or articulation in their forelimbs which transforms them from flippers or paddles into walking limbs (Mazouchova et al. 2013, also see this post on the potentially amphibious ichthyosaur Cartorhynchus). A jointed limb performs considerably better on loose substrates (such as those common on beaches, mudflats and other shoreline locations) because it enables greater control of force distribution as animals move. Immobile flippers tend to skim over or dig into sand or mud, while jointed limbs can respond to yielding substrates to maximise lift and propulsive forces. Where substrates have already been disturbed, fixed-shape flippers can struggle to get any purchase at all (Mazouchova et al. 2013).

The evolution of the plesiosaurian flipper - represented here with early sauropterygians (A - B) and true plesiosaurians (C - D) involves the development of tightly fitting bones and removal of joint mobility. This makes for a superior flipper for an underwater flier, but compromises their terrestrial capacity. Image and caption from Storrs (1993).

Assuming these findings apply to plesiosaurians - and there's no reason they shouldn't - their effectively immobile flippers present a major barrier to terrestrial activity. Plesiosaurian flippers lack both obvious bony joints or significant cartilaginous regions that would allow them to flex, so they best fit those modelled flippers which skid around or dig into the substrates they're meant to traverse. We must consider that their flippers are married to animals that are already encumbered by large size and weight, as well as the additional difficulty of drag forces operating on their bodies as they moved forward. The it hard not to imagine a beached plesiosaurian like a heavy vehicle stuck in sand, spinning its wheels as it tries to move forward.

The issues with plesiosaurian limbs do not stop there as their limb girdles are also ill-equipped for supporting their weight on land. While augmented ventrally to accommodate big downstroke muscles, the upper regions of plesiosaurian shoulder and pelvic girdles are only weakly developed. This isn't unusual for aquatic species as a major role of expanded upper limb girdles - specifically the scapulae of the shoulder, and ilium in the hips - is stabilisation of the limb girdles during terrestrial locomotion (some readers may recall us discussing this recently in context of another marine reptile, Helveticosaurus). But while adequate for life at sea, on land these small girdle elements provide only weak girdle support and thus impede locomotion, and this was probably true for plesiosaurians. Though retaining a connection between the ilia and sacral vertebrae, the articulation is weak and ligamentous, and thus unsuited to weight-bearing (O'Keefe and Chiappe 2011). Similarly, their small scapulae leave little space for muscles associated with stabilising the shoulder against the body, and the shoulder is poorly braced for terrestrial locomotion (see Rieppel 1989 for discussion, also Araújo and Correia 2015). We thus have flippers ill-suited to land-based locomotion attached to limb girdles which are maladapted to weight-bearing. These are not the features of animals that are regularly hauling themselves onto shorelines.

Pelvis of Brancasaurus brancai in lateral (A) and medial (B) view, from Carpenter et al. (2010). Note the extremely narrow ilium: this structure articulates with the vertebrae overlying the hip to act as an important brace for the pelvic girdle during terrestrial locomotion, so its small size does not bode well for the prospects of plesiosaurs leaving water.

And there are further impacts from the reduction of the scapula to be explored. The muscles that elevate our heads and necks are anchored to our scapulae as well as our vertebrae, so the size of bones making up our shoulders dictates how large muscles important to neck elevation and control (e.g. the trapezius, levator scapulae) can be. Plesiosaurians famously have large necks and/or heads, but lack the weight-saving adaptations of similarly proportioned land animals such as pneumatic tissues and reduction or displacement of neck musculature towards the body (e.g. Taylor and Wedel 2013, also see this discussion of the lifestyle of Tanystropheus). Their necks and heads must have thus been heavy compared to those of large necked or big headed terrestrial reptiles**, so we might expect substantial shoulder bones to anchor massive neck elevators if they were routinely leaving water. This casts their tiny scapulae as the exact opposite of what we might expect if these animals were routinely crawling around on land.

**To put some numbers on this, Henderson (2006), modelled plesiosaurian heads and necks with tissue densities of 1.05 g/l, about 1.5 times heavier than a value we assume for a bird or bird-like dinosaur.

The pectoral region and musculature of Rhomaleosaurus, modified from Araújo and Correia (2015). While the humerus is well muscled, the scapula is proportionally tiny compared to the chest, which has implications for shoulder stability and carriage of the head and neck.

Plesiosaurians could have developed an alternative approach to supporting the weight of their heads and necks out of water, such as bulking up the muscles surrounding their neck vertebrae. If so, we could predict structures equivalent to withers (elevated vertebral spines over the shoulders related to expanded neck musculature) in species with particularly large heads and necks. Such structures are not to be found plesiosaurians however, so I don't think this idea is compelling. This being so, it looks like neither the shoulders or anterior trunk vertebrae provide sufficient space for the powerful neck muscles needed to elevate their necks and heads on land for sustained periods. The impact of struggling to lift their heads for long intervals could include further impedance to their locomotion (additional drag, difficulty overcoming obstacles) as well as exposing their facial tissues to abrasion and other damage.

Ventral view of rhomaelosaurid Meyerasaurus victor, as figured by Smith and Vincent (2010). Note that the extensive bones of the chest, hips and gastric regions are entirely unfused: like many secondarily marine animals, plesiosaurian skeletons were likely far more cartilaginous than their terrestrial ancestors. Scale bar is 1 m.

A final, but no less significant, consideration for our inquiry is the high volume of cartilage associated with the plesiosaurian skeleton. A glut of unfused bones and loosely fitting contours between closely associated elements betrays a skeletal system held together primarily through extensive amounts of cartilage tissue. This includes areas of relevance to land-based locomotion, such as the shoulder and hip joints, the limb girdles and the region between the gastralia and ribs. In water, these softer connections wouldn't cause any issue, but on land the flexibility and softness of cartilage might weakens skeletal support and strength. The hypothesis outlined above posits that land-based plesiosaurians are essentially moving around with brute force, shoving their large masses around with motions of their flippers against large drag forces. Under this scenario, a relatively rigid and uncompromising skeletal frame would be ideal, whereas one with large volumes of cartilage would make movement less efficient.

What about small-bodied plesiosaurians?

With ,any aspects of plesiosaurian anatomy looking incompatible with terrestrial activity, we might need to play a biomechanical get-out-of-jail-free card to prevent abandonment of this concept altogether: small body size. Inescapable rules of scaling mean that a given bauplan, expressed at smaller size, can perform biomechanical feats impossible for bigger individuals. Might small plesiosaurian species or juveniles exploit greater relative tissue strength ratios, lower body masses and improved muscle power:weight ratios to haul themselves onto land, leaving only larger plesiosaurians confined to water?

The pliosaurid Thalassiodracon hawkinsi is one of the smallest plesiosaurians known at c. 2 m long, and yet it bears all the same hallmarks of incompetent terrestrial abilities as its larger relatives. Are the virtues of small size enough to justify thinking animals of this size could leave the water? Photo from Wikipedia, by the paleobear, CC BY 2.0.

I must admit that I'm skeptical even here. Anatomically speaking, small plesiosaurians have the same terrestrially-inhibited anatomy as their larger relatives: inflexible flippers, high cartilage volumes, and low weight bearing capabilities for the body, head and neck. Smaller size could make all the difference, but size alone is of ambiguous significance to predictions of extinct animal behaviour. It's clearly a factor in what fossil species could and couldn't do, but it should not overshadow better established relationships between form and function when considering extinct animal lifestyles (see also: flight in giant pterosaurs). So while small size theoretically makes terrestrial locomotion more achievable for an aquatic animal, it's ultimately circumstantial evidence for this behaviour and not an especially compelling counterargument.

And as a final, closing thought on this, it's also worth considering that plesiosaurians were generally large bodied creatures. Genuinely small species (such as the c. 2 m long Thalassiodracon hawkinsi) are rare and even their offspring were large (e.g. 1.5 m calf lengths in 4.7 m long mothers - O'Keefe and Chiappe 2011). Mesozoic shorelines were probably not swarming with small plesiosaurians even if they did have superior terrestrial capabilities, because by and large plesiosaurians weren't small creatures.

Bring on the blue paints

So, should palaeoartists get back to painting plesiosaurs out of water? Sadly, no. Any notion that plesiosaurians were capable of hauling themselves onto land is not only unnecessary in light of what we know of their reproductive biology, but also contradicts much of what we understand about the functional morphology of semi-aquatic animals. Their four-flipped construction looks a little more terrestrially-apt than the bodies of a whale or ichthyosaur, but I suspect an accidentally beached plesiosaurian would be in just as much trouble as these more classically-shaped marine forms. History shows that we can make beached plesiosaurians look half convincing in art, but it's a hollow victory: the science is not on our side.

I still find it odd that there isn't a more detailed discussion of plesiosaurian - or maybe broader sauropterygian - terrestrial capability in marine reptile literature. After all, many clades generally regarded as relatives or even ancestral to plesiosaurians are regarded as semi-aquatic (e.g. nothosaurs, Helveticosaurus) and there has to be an interesting story there regarding the progressive abandonment of land. Hopefully studies along these lines will be performed before we're much older. But for the time being, I'll be restoring all my plesiosaurians in water, where they almost certainly belonged. I'll leave you with this painting of Pliosaurus kevani in their rightful habitat.

Pliosaurus kevani large and small, at home in the sea. Junior is particularly happy that it doesn't have to venture out onto land, probably because it's always freezing cold getting out of the water, and pliosaurids were surprisingly wimpy about that sort of thing. #palaeofact

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This blog is sponsored through Patreon, the site where you can help online content creators make a living. If you enjoy my content, please consider donating $1 a month to help fund my work. $1 might seem a meaningless amount, but if every reader pitched that amount I could work on these articles and their artwork full time. In return, you'll get access to my exclusive Patreon content: regular updates on research papers, books and paintings, including numerous advance previews of two palaeoart-heavy books (one of which is the first ever comprehensive guide to palaeoart processes). Plus, you get free stuff - prints, high quality images for printing, books, competitions - as my way of thanking you for your support. As always, huge thanks to everyone who already sponsors my work!

References

• Carpenter, K., Sanders, F., Reed, B., Reed, J., & Larson, P. (2010). Plesiosaur swimming as interpreted from skeletal analysis and experimental results. Transactions of the Kansas Academy of Science, 1-34.
• Cheng, Y. N., Wu, X. C., & Ji, Q. (2004). Triassic marine reptiles gave birth to live young. Nature, 432(7015), 383.
• Ellis, R. (2003). Sea dragons: predators of the prehistoric oceans. University Press of Kansas.
• Everhart, M. J. (2000). Gastroliths associated with plesiosaur remains in the Sharon Springs Member of the Pierre Shale (Late Cretaceous), western Kansas. Transactions of the Kansas Academy of Science (1903), 64-75.
• Henderson, D. M. (2006). Floating point: a computational study of buoyancy, equilibrium, and gastroliths in plesiosaurs. Lethaia, 39(3), 227-244.
• Liu, S., Smith, A. S., Gu, Y., Tan, J., Liu, C. K., & Turk, G. (2015). Computer simulations imply forelimb-dominated underwater flight in plesiosaurs. PLoS computational biology, 11(12), e1004605.
• Mazouchova, N., Umbanhowar, P. B., & Goldman, D. I. (2013). Flipper-driven terrestrial locomotion of a sea turtle-inspired robot. Bioinspiration & biomimetics, 8(2), 026007.
• Motani, R., Jiang, D. Y., Chen, G. B., Tintori, A., Rieppel, O., Ji, C., & Huang, J. D. (2015). A basal ichthyosauriform with a short snout from the Lower Triassic of China. Nature, 517(7535), 485.
• Muscutt, L. E., Dyke, G., Weymouth, G. D., Naish, D., Palmer, C., & Ganapathisubramani, B. (2017). The four-flipper swimming method of plesiosaurs enabled efficient and effective locomotion. Proc. R. Soc. B, 284(1861), 20170951.
• O’Keefe, F. R., & Chiappe, L. M. (2011). Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia). Science, 333(6044), 870-873.
• Renesto, S., Lombardo, C., Tintori, A., & Danini, G. (2003). Nothosaurid embryos from the Middle Triassic of northern Italy: an insight into the viviparity of nothosaurs? Journal of Vertebrate Paleontology, 23(4), 957-960.
• Rieppel, O. (1989). Helveticosaurus zollingeri Peyer (Reptilia, Diapsida) skeletal paedomorphosis, functional anatomy and systematic affinities. Palaeontographica Abteilung A, 123-152.
• Sander, P. M. (1988). A fossil reptile embryo from the Middle Triassic of the Alps. Science, 239(4841), 780-783.
• Seeley, H.G. (1896) On a pyritous concretion from the Lias of Whitby. Annual Report of the Yorkshire Philosophical Society, 1895, 20–9.
• Storrs, G. W. (1993). Function and phylogeny in sauropterygian (Diapsida) evolution. American Journal of Science, 293(A), 63.
• Street, H. P., & O'Keefe, F. R. (2010). Evidence of pachyostosis in the cryptocleidoid plesiosaur Tatenectes laramiensis from the Sundance Formation of Wyoming. Journal of Vertebrate Paleontology, 30(4), 1279-1282.
• Taylor, M. A. (1981). Plesiosaurs-rigging and ballasting. Nature, 290, 628-629.
• Taylor, M. A. (1986). Marine reptiles: Lifestyle of plesiosaurs. Nature, 319(6050), 179-179.
• Taylor, M. P., & Wedel, M. J. (2013). Why sauropods had long necks; and why giraffes have short necks. PeerJ, 1, e36.

Pterosaurs, such as the newly described Jurassic species Klobiodon rochei, are magnets for palaeontological cranks: those individuals who harbour and promote idiosyncratic and problematic ideas about palaeobiological topics. Some cranks are a genuine nuisance for educators, but they are easy enough to spot and avoid if you know their characteristics. Say, that sounds like a good idea for a blog post.

Like many popular sciences, palaeontology attracts individuals harbouring what can kindly be called ‘alternative’ or ‘fringe’ ideas: interpretations of evolutionary relationships, animal biomechanics or other facets of palaeobiology that contrast with ‘mainstream’ science. Such individuals are generally referred to as "cranks" - a term defined at Wikipedia as "a person who holds an unshakable belief that most of his or her contemporaries consider to be false". While most crank palaeontology is confined to obscure literature or forgotten corners of the internet, and is therefore pretty harmless, some cranks are major sources of misinformation thanks to their prominent, professional-looking websites, deals with mainstream book publishers, or careers in public outreach exercises.

Cranks are thus a real issue for palaeontological educators and science communicators. Students, teachers and naive members of the public are all potential victims of crankery, and many of us have witnessed crank media being embraced or shared by well-meaning individuals. Among those of us interested in science and outreach, cranks are a semi-regular topic of conversation: how do we combat their miseducation? Ignore them? Engage them on social media? Take them on in public debates? I don't know that there's a right answer, but one approach we can use is helping less experienced individuals recognise crankery when they find it. As with most peddlers of alternative ideas and pseudoscience, palaeontological cranks have characteristic behaviours and interests that stand out quickly once you learn what they are, and this can only help us avoid being hoodwinked by their unique brand of miseducation.

This, then, is my attempt to prime readers for recognising palaeontological crankery. In the interests of making this article as accessible as possible I've attempted to use easily understood, plain-English throughout. I'm dividing the post in two: first, we'll outline the commonest subjects of palaeontological crankery, so as to let readers know when to be extra alert for crank output; and in the second section, we'll look at some crank red flags which should set our sceptical systems to maximum alert. It's worth noting before we dive in that I'm only concerned with 'true' palaeontological cranks here, and will not be tackling young earth creationism, evolution deniers or palaeo-themed cryptozoology. Those are all worthy topics but are well beyond our scope today. I'm also going to generally avoid naming and linking to specific cranks or sources in this article, on grounds that any publicity is good publicity.

The favoured subjects of palaeontological cranks

Claims of remarkable fossil discoveries
Probably the commonest form of palaeontological crankery is the claim of having a significant fossil discovery, yet to be recognised by science. This might be an amazing new fossil, such as a complete pterosaur head in amber, or it could be the identification of overlooked extra bones, soft-tissues or other features on an existing specimen. Cranks making these claims vary as to whether or not they've actually seen the specimens they're discussing, and sometimes they work only from images found in papers, books or on websites. These 'discoveries' are often the crux of all subsequent output from that individual, whether they are simply showing off their specimens on a website or using them to inform ideas about evolution and biomechanics.

Most fossils don't escape some damage en route to discovery by humans: cracks, breaks, distortion of other kinds are common, as shown here on the broken holotype skull of the pterosaur Lacusovagus magnificens. But some individuals will not see these as artefacts of preservation and instead assume that they represent overlooked structures such as teeth, bone divisions or vestigial elements. Given that this work is often based on photos alone, this implies that the experts who spent hours or days studying the actual specimens have missed obvious structures, but that the crank is able to see them without difficulty in a photograph.

A phrase tossed about lots when talking about these claims is 'pareidolia' - the phenomenon of seeing significant patterns or forms in what is actually random visual data. Like perceiving a face on Mars or Jesus on a slice of toast, these individuals 'find' significance in rock structures, cracks on fossils, detritus in amber, or even artefacts of image reproduction. Overwhelmingly, the response from people who've experienced the fossils in question is that these claims represent major over-interpretation of specimens.

Rearranging evolutionary trees
Most would agree that determining the relationships of species with one another is a challenging endeavour, but that generations of anatomical and genetic-based investigations have created a reasonable insight into the broad outline of life's evolution. Not so, according to many cranks, several of whom argue that major branches of evolution (mostly certain charismatic tetrapods) are misplaced in 'mainstream' takes on life's evolutionary tree. Oddly, few cranks agree on exactly which relationships are incorrect. Are birds pterosaurs? Are mammals archosauromorphs? Are pangolins late-surviving stegosaurs? There are lots of alternatives out there, leaving only a smattering of die-hard BAND ("Birds Are Not Dinosaurs") supporters agreeing over where we've got our interpretation wrong.

Amazingly, there are still people out there who doubt the bird-dinosaur link, despite the literal thousands of fossils and hundreds of studies that evidence the origin of birds among theropod dinosaurs. Even relatively non-birdy theropods, like Gorgosaurus libratus, shown here, have skeletons littered with features that are otherwise only seen in bird-line tetrapods.

The great size and peculiar anatomy of many fossil animals - but especially certain Mesozoic reptiles - draws crank attention when they don't buy into accepted modern interpretations of their lifestyles. How could large dinosaurs support their great weight on land? How did plane-sized pterosaurs fly? How could an animal the size and shape of a giant theropod be hidden from prey? Rather than deriving answers from disciplines that have a genuine bearing on these issues, such as biomechanics, fossil trackways, palaeoenvironmental interpretations, or the ecology of living predators, cranks instead propose radical solutions. Perhaps all dinosaurs were aquatic? Maybe Earth's atmosphere was thicker, or gravity was radically different from how we know it today?

Each of these 'solutions' is actually a rabbit hole of problems, errors and logical fallacies that we could disappear into for some time. It's common for cranks to cite something from their background that makes them uniquely able to see biomechanical problems where others can't. My favourite example is a high-school physics teacher who argues that they understand giant dinosaurs and pterosaurs better than anyone because of a particularly formidable understanding of square-cube law. What we're really seeing in these cases is Dunning-Kruger effect: a cognitive bias where individuals rank their cognition of a topic much higher than anyone else, even if they have only a slight or even problematic understanding of the subject in question. I can give no better example of this than the recent and public debate over Too Big to Walk, a book by microbiologist Brian Ford (published in 2018) which proposes that dinosaurs were incapable of supporting themselves on land and must have been confined to aquatic habits. Ford's thesis is outlined here and in other articles online, with responses by palaeontologist and dinosaur specialist Darren Naish here, here and here. All palaeontological crankery is reliant on Dunning-Kruger to a certain extent, but crank arguments about the lifestyles or biomechanics of prehistoric reptiles are particularly good examples.

10 Red flags and pointers for spotting crank palaeontology

If these are the current hot topics in palaeontolgical crankery, how do we distinguish genuine scientific discussions of these matters from crank nonsense? Given that most cranks seem to regard themselves as somehow 'special' - being of unique abilities and insight, or at least due respect for authoring some critical scientific breakthrough - it must pain them to learn that they are actually extremely similar and predictable in how they present their work, talk about themselves and interact with others. This is to our benefit, as it gives us excellent means to guauge the general reliability of whatever it is we're reading or listening to. Some of these checks and tells are listed below. This list is not exhaustive, but if an article, presentation or book hits a number of these marks you probably want to treat their content with extra scepticism.

1. The creation of a problem to solve
Our first red flag is the prediction of cranks to manufacture problems that need solving. They confidently make grand claims like "scientists have never explained this" or "subject X has never been satisfactorily investigated". Such statements are an essential foundation of crank thinking because if these 'problems' didn't exist, the crank would have nothing to 'solve'. While many palaeontologically savvy readers will smell these rats immediately, such claims stand a chance of duping naive readers. Be cautious when reading any sweeping, unreferenced suggestion that we're entirely wrong or misinformed about a particular facet of palaeontology. It's actually very difficult to think of a major palaeontological area where all previous work is totally useless, and such claims are more likely to be someone sidestepping science in order to create space for a pseudoscientific approach.

2. Avoidance of conflicting data or fields of study
A sure-fire crank giveaway is the dismissal of data contradicting with their ideas, even if that means rejecting an entire scientific discipline. Science works by testing ideas using different methods, not through cherry picking the results and methods that best support our preferred ideas. If someone states that DNA-based methods for reconstructing evolutionary trees are bogus, or that fossil footprints have no bearing on the habitat preferences of giant extinct animals, there's a good chance that they're attempting to deflect data that conflicts with their ideas.

3. Over-confidence
One of the most defining features of cranks is their confidence. Genuine palaeontologists, like all scientists, learn early in their careers to be careful about overstating certainty. Outside of describing raw data (e.g. reporting measurements or the outcomes of analyses) they use cautious phraseology like "this infers", "our findings indicate", and "we were unable to replicate Author X's findings". This accepts that interpreting fossil life is always a work in progress and that our work is rarely the last word on a given topic. Cranks, on the other hand, tend to write boldly and without reserve: "this is", "I have shown" and "Author X is blinkered and wrong". This level of confidence is not only misplaced (cranks revise their ideas as often as legitimate scientists, often without documenting why) but characterises a dangerous level of self-belief for someone purporting to conduct legitimate science.

Cranks are drawn to large dinosaurs like Dreadnoughtus schrani when they cannot, or will not, accept that they were capable of walking on land, which leads to ideas of dinosaurs living largely in water, in denser atmospheres, or under reduced gravity. Huge swathes of data from anatomy, geology and dinosaur trackways show that none of these concepts are correct. It also seems lost on cranks that plenty of non-dinosaurian Mesozoic organisms would struggle to live in denser atmospheres, low gravity or waterlogged habitats. It's almost like these ideas are not well thought through.

4. An embarrassment of scientific riches
It's rare for cranks to make one bold claim. Instead, they frequently have a slew of amazing, game-changing discoveries. They don't have one amazing fossil, they have many. Palaeontologists have not got the anatomy of one species wrong, they've overlooked major anatomical characteristics across huge groups. And it's common for cranks to suggest that their work has a significant bearing on all manner of palaeontological mysteries: that their idea on dinosaur locomotion also explains giant pterosaur flight, that their anatomical criteria for understanding the evolution of reptiles can be applied, without modification, to mammals or birds. It's a hallmark of crankery to have all the answers - or at least more answers than 'mainstream' scientists.

Claims for so many ground-breaking discoveries should immediately trigger our scepticism. Yes, there are skilled and prolific scientists who make numerous significant contributions to our collective knowledge, but they do not make them every week. Good science takes time: time to collect and analyse data, time to document and report the findings, time for peers to check the work, and time to publish it in a suitable venue. While the crank may view their churning out of game-changing revelations as the inevitable consequence of a self-led scientific revolution, they're actually exposing their lack of rigour, willingness or ability to have their work vetted by relevant experts.

5. An abundance of self-citation
Does the article you're reading extensively cite the work of the author, and almost always in an affirming light? It would be wrong to say that genuine scientists do not self-cite, or even that some do not over cite their own work (scientists have egos too, many have rather big ones), but if you're reading a work that is extensively citing and complementing the author's own work, be wary: this is often a sign of crankery. This red flag flies especially high if the author is demeaning the work of others while holding their own work in high regard (see below).

6. Knowing your authors
In science, what is said matters more than who says it, but when a questionable claim is made the integrity of the author can be a useful indicator of credibility. Whether we like it or not, reputation matters. We should be extra sceptical with proposals made by those with a history of quackery or no background in the field they're claiming expertise in. This is not to say that amateur or non-professional individuals can't or won't have insights on palaeontolgical matters overlooked by experienced researchers, but folks without experience or training in a relevant field are more prone to making mistakes and overlooking data. It’s quite easy to research scientists and educators nowadays by simply Googling their names, or by asking around in the right internet venues. Sometimes this very quickly reveals whether you should be taking that individual seriously, or if you need to take a more cautious approach to their ideas.

7. Misleading credentials and other trickery
While some cranks decry academic titles, others flaunt their credentials to add support to their claims. But simply having a high-level qualification does not make someone an expert in all subjects. If someone is making questionable claims, check out what their qualifications are actually in: having a postgraduate qualification in microbiology or graphic design does not automatically equate to an equivalent understanding of dinosaurian biomechanics. Similarly, be wary of cranks making up official-sounding institutions as their place of research. There's no restriction on naming your own institution or society so cranks can create 'scientific' or 'educational' bodies as easily as I can call my garden shed the "Mark Witton Institute of Natural History". A quick round of Googling will quickly expose these institutions and credentials for what they really are. Needless to say, if someone is distorting their credentials in order to seem more authoritative, you've got an excellent reason to question pretty much everything they say.

That most cranks have only a superficial knowledge of palaeontology is demonstrated by their focus on well-known and charismatic species such as big dinosaurs and pterosaurs. It's rare to see cranks applying their ideas to more routine, less exciting species like extinct fish, invertebrates or even crocodyliforms like Hulkeopholis willetti. My hunch is that most cranks learn about palaeontology largely through popular media and if so, this explains why their ideas are so easily dismissed. Even basic training in palaeontology is enough to expose major holes in their ideas.

8. A predilection for criticism and personal attacks of scientists
Because cranks believe they have a superior scientific insight they are often extremely critical of other researchers. This seems to get worse as the crank gets older and has faced long-term rejection from the scientific community, and it can manifest itself in particularly nasty and underhand ways: obsessive and ultra-detailed 'criticisms' of published works; personal attacks and harassment of scientists; accusations of institutions being dogmatic, blinkered or even fundamentalist in their adherence to 'mainstream' views; and even attempts to dissuade prospective PhD students from legitimate postgraduate programmes. You don't see comments like this in legitimate research because genuine science is concerned with hypotheses and ideas, not venting frustrations at individuals or institutions. Crank hostility can be especially obvious if they have a comment field on their websites: when challenged, they are often quick to vent their frustrations.

9. The Galileo Gambit
Another major red flag common to all cranks is their frequent comparison between themselves and scientists who received establishment pushback against their ideas - Wegner, Galileo, Darwin and so on. The folly of the Galileo Gambit is well established and we needn't outline it in detail here, it will suffice to point out that invoking these big names is clear evidence of self-belief in their own abilities against overwhelming evidence to the contrary. Note that scientists making genuine research contributions never use this defence when proposing ideas they know will cause upset or controversy. If you see someone comparing themselves in this way to a historically persecuted scientific figure, there's a very good chance they're a dyed-in-the-wool crank.

10. Beware of Big Palaeo!
Saving the best until last: yes, unbelievable as it is, there are individuals who suggest mainstream scientists are somehow organising against them to suppress their work. While maybe not imagining something as sinister as the Big Pharma conspiracy, some cranks infer that palaeontology is governed by individuals who dictate what is and what isn't acceptable science, and who forbid the publication of work that challenges the status quo. The plot thickens with universities not simply training scientists, but actually indoctrinating them into this way of thinking. This casts PhDs not as experts in their subject, but as brainwashed members of the Big Palaeo cult. In controlling the ebb and flow of palaeontological science these individuals are able to maintain lofty academic positions and secure grant money. In my experience, this claim tends to follow the crank's papers being rejected from academic journals or finding that no palaeontologists will agree with their interpretation of an (allegedly) amazing fossil.

As someone with academic experience myself, I find this mindset genuinely fascinating. It gives a real insight into how some cranks see the world: so convinced are they of their own findings and significance thattheir rejection from academia can only reflect a global, organised conspiracy. In reality, their lack of academic recognition reflects the fact that any average scientist can spot fatal errors in their proposals. Moreover, the idea that palaeontologists, or any scientists, suppress controversial new ideas is ludicrous. Within the well-publicised realm of dinosaur science, just some recently published contentious ideas include the recovery of soft, unlithified proteinaceous tissues in 80 million year old fossil bones (Schweitzer et al. 2005), that Spinosaurus was a weirdly proportioned, archaeocete-like quadruped (Ibrahim et al. 2014), and that major branches of the dinosaur evolutionary tree have been incorrectly arranged for a century (Baron et al. 2017). These are bold claims that remain debated, but they were published nonetheless. The difference between these papers and crank ideas is simply the evidence and methodologies used to justify their conclusions - that's all there is to it. We could write a whole essay on how flawed the idea of a Big Palaeo conspiracy is but, in short, if you encounter anybody claiming their work is being silenced by a conspiracy of palaeontologists they are, without doubt, an embittered crank of the highest order.

These are just a few giveaways that you're dealing with a palaeontological crank, hopefully they're of use to folks less familiar with the more questionable parts of palaeontological outreach. Some readers may have identified some parts of the above list as common hallmarks of more general crankery, and that's no coincidence: as mentioned above, although crank subjects change, their behaviour and public presentation is remarkably consistent. There are longer, more detailed discussions of crank detection available online, but what we've outlined here should be enough to equip most readers with an early warning system for crankery. We've not, of course, answered the question about what to do with cranks when we identify them. Should we ignore them? Alert others about them? Contact them about their bad science? That's another long discussion (and a much murkier one) however, so that'll have to wait for another time.

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References

The southerly approach to one of the most spectacular collections of historic palaeoartworks on the planet: the Crystal Palace prehistoric animals. Over 30 sculptures depict Victorian takes on prehistoric faunas in a remarkable and unique feat of engineering, artistry and scientific outreach. Much about how the models were assembled and the specific science informing their anatomy is lost to history, leaving us to piece it together from written accounts, surviving draft artwork, and the models themselves. This photo is from 2013, some of the models have been restored since then.

Part of the enduring appeal of the Crystal Palace sculptures is the mysteries of their construction. While the generalities of the project are well documented (e.g. Rudwick 1992; Doyle and Robinson 1993; McCarthy and Gilbert 1994; Secord 2004, also see this FOCPD summary), few documents are known specifying how the sculptures were built, and the scientific rationale behind them. Some details of their construction can be deduced by examination of the models themselves, and both Hawkins and Owen put their general scientific approach on record (Owen (1854) in particular reads like a modern summary of palaeoart practises), but it remains difficult to ascertain exactly how Hawkins decided on the form of each species. Adding depth to the mystery are suggestions that Owen's contributions may have not have been as substantial as generally assumed, and that his expertise was only sought as the designs approached their final phase and full-size construction was set to begin - too late, perhaps, for major revisions to Hawkins' drafts (Secord 2004). Moreover, while Hawkins' attention to Owen's work is clear, he also evidently relied on other sources of information and his own intuition on many occassions. This may explain why Owen sometimes distanced himself from aspects of the models in a 1854 guidebook to the models, as well as in newspaper interviews (Secord 2004). Nevertheless, documents authored by both Owen and Hawkins suggest mutual respect and admiration for one another (Owen 1854; Hawkins 1854), although it's interesting that each eventually claimed to be the greater intellectual influence on the project (Secord 2004).

Scene from Benjamen Waterhouse Hawkins' temporary workshop: a large wooden structure in the grounds of Crystal Palace Park. Images like this - which feature (clockwise from top left) Palaeotherium, Iguanodon, Hylaeosaurus, Dicynodon and "Labyrinthodon" - give valuable insights into the creation of the Crystal Palace Prehistoric Park, but shed little light on the science influencing their restoration from fossil bones. Note the corvid and rodents in the foreground: written accounts suggest Hawkins' workshop was not always a luxurious place to be. Illustration by Philip Henry Delamotte, 1853, image in public domain.

Recently, I've been working with the Friends of Crystal Palace Dinosaurs to restore the Crystal Palace extinct animals as we know them today for their website. As part of that process, I've been providing notes on how accurate the models are to current science as well as against fossil data available to Hawkins in the early 1850s. This has proven fascinating, confirming Hawkins' talents and insight while also raising several questions about his process and palaeoart philosophy. We may never know Hawkins' thought process in detail, but we might be able to 'reverse engineer' his models back to specimens known pre-1854 and, through clues worked into his models, establish what science, artworks and extant species influenced his designs. Over the next three posts, I thought it would be of interest to share some of these thoughts, as well as my modern takes on the Crystal Palace species. Edited versions of these notes also appear at the Friends of Crystal Palace Website, and more will follow in the near future as we wrap up this project up. I'm going to tackle the sculptures more or less as they appear in the park as you walk from the geologically oldest models (the Dicynodon) to the youngest (Megaloceros).

Dicynodon

The Crystal Palace Dicynodon, as seen in 2013. The larger model in the top photo, and the focus of the lower photo, is D. lacerticeps, the smaller sculpture is D. strigiceps. Note the turtle-like bodies and long tails, but also the presence of obvious clawed feet instead of flippers.

There are two Dicynodon sculptures in Crystal Palace, one large, one small. Particulars of their bodies and size indicate that they are meant to be different taxa. Owen (1854) indicates that the larger statue - "with the bulk of a walrus" - is D. lacerticeps, but he did not specify the identity of the smaller animal. He provides a clue, however, in stating it is a species with somewhat owl-like facial features. This must indicate that the smaller model is D. strigiceps, a species Owen named in 1845 that literally translates to 'owl-faced Dicynodon'. D. lacerticeps is the type species of Dicynodon and remains valid today, but strigiceps was regarded as a nomen dubium by Kammerer et al. (2011). The identification of D. lacerticeps as the large animal is peculiar, as it is not a large species - its skull was just over 15 cm long. We know that Hawkins attempted to capture the size of his animals accurately (Hawkins 1854), so perhaps other Dicynodon material factored into this decision.

The Crystal Palace Dicynodon are famously turtle-like in form, a circumstance reflecting Dicynodon being almost entirely represented by cranial material in the 1850s. These skulls demonstrated the basic shape of the skull and their strange turtle-meets-walrus nature but, as noted by Owen (1854), the rest of the sculptures are purely conjectural. Owen regarded dicynodonts as amphibious (Owen 1845, 1854) and Hawkins seems to have ran with this concept, presumably also inspired by the turtle-like features of the skull. Details of the sculptures' feet show that Hawkins was probably modelling these creatures on more terrestrially-adept turtles, and I wonder if the three ridged, sculpted keels, developed claws and long, scute-lined tails specifically indicate influence from snapping turtles. As we'll see, Hawkins often took inspiration, and entire anatomies, from living species in his work.

Today, we imagine dicynodonts very differently to our Victorian colleagues. This image shows Aulacephalodon bainii (the larger species, an animal known to Owen, and possibly referenced in the size of the D. lacerticeps sculpture) and the smaller dicynodont is Cistecephalus microrhinus (a species only distantly related to D. lacerticeps and A. bainii). This image will be featured in an upcoming book, also themed around historic palaeoart.

Dicynodont anatomy is now very well known and contrasts markedly with Hawkins’ sculptures. While their heads are reasonable proxies for dicynodont crania and consistent with contemporary reconstructions (e.g. Owen 1845), they seem a little ‘snouty’ compared to the short, shear-faced muzzles we now known from well-preserved dicynodont skulls. More obvious differnces are that dicynodonts have robust limbs adapted for terrestrial life, and many species were burrowers: they accordingly had rotund, longish torsos, not wide, flat ones. Though no dicynodonts had shells or armour, we are still uncertain what sort of skin they had. Given their relationship to mammals some artists restore dicynodonts with fur, but we have yet to find any evidence of this integument type so deep within our evolutionary history. The recovery of hair from a Permian coprolite (Bajdek et al. 2016) suggests some synapsids from this time may have been furry, but the most parsimonious candidates are our closest Permian ancestors, the cynodonts, not the more distantly related dicynodonts. We still think, as demonstrated in Hawkins’ model, that dicynodont snouts were largely covered with a cornified beak sheath however, with the tusks projecting either side (Kammerer et al. 2011).

“Labyrinthodon”

A trio of "Labyrinthodon", photographed in 2013. There are two species here, the larger being "L. salamandroides", the smaller "L. pachygnathus". Note the palatal teeth in the right animal and the similarity between L. salamandroides and an Owen sketch of Labyrinthodon as the Chirotherium trackmaker.

The three Crystal Palace “Labyrinthodon” reconstructions are attempts to rationalise several pieces of unrelated fossil data, so it is unsurprising that the results are far from the reality of the species they are meant to represent. But while some of the most dated models scientifically, they raise some interesting questions about how Hawkins approached his reconstructions.

Depicted as giant frog-like creatures, Hawkins’ sculptures show close attention to illustrations of “Labyrinthodon” as interpreted by Owen (e.g. Owen 1841a, 1842; also see Benton and Gower 1997) and capture some details of the skull and tooth material then referred to this genus. Particularly notable are the palatal teeth - this excellent attention to anatomical detail, especially given that visitors have to be right next to the sculptures (or looking with binoculars) to see them. Their mix of smooth and warty skin is surely based on living amphibians, and serves to distinguish the models of “L. pachygnathus” (smaller, warty-skinned) from “L. salamandroides” (the larger, smooth-skinned model) (McCarthy and Gilbert 1994). Owen famously linked "Labyrinthodon" with trackways now referred to pseudosuchians, but in doing so rationalised and illustrated the trackmaker as making prints with opposite limb sets, so the left prints were made with the right feet, and vice versa. This detail is absent from Hawkins’ models, despite his general attention to Owenian ideas. Perhaps even he struggled to make this bizarre hypothesis a reality.

Modern takes on “Labyrinthodon” are very different to the creatures displayed at Crystal Palace. What Owen and Hawkins considered “Labyrinthodon” is now rightfully called Mastodonsaurus, the former name being Owen’s attempt to replace Mastodonsaurus with a title he thought better suited the animal (Owen 1841a). Of the depicted species, “L. salamandroides” has been subsumed into M. jageri, and the fossils referred to “L. pachygnathus” are a mix of mastodonsauroids and archosaurian remains (Benton and Gower 1997; Damiani 2001). The latter point vindicates Hawkins' now archaic-looking approach to restoring Mastodonsaurus. The idea of a sheep-sized prehistoric frog seems outlandish in the 21st century, it was an entirely sensible interpretation of Owen's take on the available fossil material, from the proportions of the body to the upright limbs. I find the capturing of the "L. pachygnathus" jawline and dentition especially commendable.

Mastodonsaurus jageri, the 'real'"Labyrinthodon", striking at the rhynchosaur Fodonyx spenceri. Far from being an oversize frog, M. jageri occupies anatomical space somewhere between a salamander and alligator.

We now know that Mastodonsaurus resembled a giant salamander more than a frog, though in truth no living amphibian is a close analogue for this often giant Triassic form. A large, flattish head dominates a long, slender body with reduced limbs. The skull is covered with sculpted and textured bones somewhat reminiscent of crocodylian skull surfaces, and detailed investigation suggests this records a tight, tough facial skin (Witzmann 2009). Also like crocodylians, Mastodonsaurus eye sockets are situated on the top of the skull, not the sides as depicted at Crystal Palace. This was a peculiar decision from Hawkins, given that good Mastodonsaurus skulls were known in the early 1800s (e.g. Plieninger 1844), and that Owen knew about them (1854). Hawkins older illustrations and draft Labyrinthodon model (which was presumably shown to Owen) also show flatter heads. Do the fleshy-faced, side-eyed Crystal Palace amphibians reflect Hawkins paying more attention to frogs than Mastodonsaurus fossils? It may, as there are several other examples of Hawkins' models overriding fossil data with extant animal form, as we'll see throughout this review. Alternatively, were they errors? A misguided revision suggested by Owen or someone else? Was Hawkins simply following the illustrations of others, such as that presented in Owen's (1854) guide? Whatever the cause, this is a clear example of Hawkins not using fossil data where he could have done, in contrast to his sometimes exacting reproductions of anatomy in other areas.

Ichthyosaurs

In terms of scientific credibility, Hawkins’ three ichthyosaur statues have probably held up best of all his non-mammalian sculptures. This undoubtedly pertains to ichthyosaur skeletons being entirely known from very early in palaeontological history, as well as their familiar whale- or fish-like form. I consider them a good measure of Hawkins’ skill as a palaeoartist because it puts him on a more equal footing with modern practitioners, and suggests that when he had comprehensive datasets and suitable modern analogues he was able to produce very reasonable interpretations of fossil forms. It was largely a lack of information, not poor knowledge of anatomy and zoology, that lead to the inexactitude of the Crystal Palace models. There are three species of ichthyosaur on display, each distinguished by size and proportions, and once all considered different taxa of Ichthyosaurus. In modern parlance, they are Ichthyosaurus communis (the mid-sized ichthyosaur model), Temnodontosaurus platydon (the largest) and Leptonectes tenuirostris (smallest).

The Crystal Palace icthyosaurians in various states of visibility and repair. Top, Leptonectes tenuirostris as photographed in 2018 (I don't have any good photos of this model on account of it being hard to access and, when I was able to see it properly, the site was overgrown with lush vegetation); middle, Ichthyosaurus communis in 2018; bottom, Temnodontosaurus platydon (another 2013 photo, but this reflects the current state of the model - notice the contrast with the restored sculptures).

Much about Owen’s views on ichthyosaurs, and much of how Hawkins rendered them, remains accurate today. Owen (1854) specifically mentions the presence of smooth, scale-less skin, predicts some sort of fin at the end of their tails (identified in by Owen in 1840(a), though he was uncertain of the shape) and large eyes in these animals. We still restore ichthyosaurs in this way, albeit with some additional guidance and confidence from fossilised ichthyosaur body outlines and soft-tissues (e.g. Lindgren et al. 2018). Major additions to post-Crystal Palace reconstructions include the presence of a dorsal fin, tall and crescent-shaped tail fins, and more generous allocations of soft-tissue across the body as befitting fully marine, whale-like creatures. The presence of large eyes was then, as now, deduced not from large eye sockets but from the enormous scleral bones found in fossil ichthyosaur skulls. Owen’s statement that the function of these bones was supporting and protecting the eye is also correct, although it’s unlikely that the sclerotic ring was conspicuous in life as Hawkins depicted it. Plenty of living animals have large sclerotic rings, but they are hidden beneath eyelids and other anatomy.

An unusual property of the Crystal Palace models is the skin on their flippers, which has a very obvious scaly appearance. This reflects the Owenian hypothesis that the bones of the flippers were somehow reflected in the overlying skin scales (Owen 1841b), which Hawkins faithfully reproduced on his models. This seems unlikely given what we now know of fossilised ichthyosaur skin and the relationships between bone texture and skin anatomy. Hawkins was not solely guided by fossils in his restorations however, with details of the ichthyosaur faces reflecting whales and dolphins. This is particularly evidenced by the dolphin-like grooves and lips along their jaws, and seems entirely reasonable given what we know of ichthyosaurian skulls and the relationship between jaw bone surfaces and facial features.

A modern restoration of Temnodontosaurus eurycephalus (the larger, strand-feeding species) and Ichthyosaurus breviceps (the prey animals). In many ways, not so different from Hawkins' take.

Two aspects of the models date them firmly to palaeontology's early years. The first is that they are meant to be crawling around in shallow water, not swimming along the water surface (Owen 1854). This reflects a now long-abandoned view these reptiles could come ashore to sleep or for reproductive purposes. Secondly, all three ichthyosaur models have a great degree of flexibility in their tails, which is no longer considered plausible. The three sculpted species likely had varied capacity for tail flexion in life, with two species (Temnodontosaurus and Leptonectes) probably having more flexible tails than the relatively thunniform ('tuna-like') Ichthyosaurus communis. None had an ability to attain the eel-like tail shape reflected in the Crystal Palace models, however. This was not a mistake unique to Hawkins, but a fairly typical way of restoring ichthyosaurs in th early 1800s.

Plesiosaurians

Complete plesiosaurian skeletons allowed Hawkins to reconstruct them in a generally credible light, though the results were not as precedent as his takes on ichthyosaurs. To be fair, plesiosaurians are not as intuitive to reconstruct as ichthyosaurs and many aspects of their anatomy and functionality are debated even today. Making three-dimensional plesiosaurian sculptures just decades after their fossils were found was no mean feat, and Hawkins' models no less credible than other mid-19th century takes on these animals. Three models were created and, though similar, they have varying proportions and sizes on account of representing three species. Today, we classify these as Plesiosaurus dolichodeirus, “Plesiosaurus” macrocephalus, and Thalassiodracon hawkinsi.

Plesiosaurians of Crystal Palace. These are all restored to their former glory now (as per the top image) but, as with the ichthyosaur images above, I'm forced to use older, shoddier photos for two models because of all that fantastic greenery. Top, “Plesiosaurus” macrocephalus in 2018; middle, Thalassiodracon hawkinsi (2013 - note missing flipper, now replaced); bottom, Plesiosaurus dolichodeirus (2013). I've taken these identifications from McCarthy and Gilbert (1994), but I'm not sure they're correct. Surely the middle is the short-necked macrocephalus? Owen's guide is not entirely clear on the matter, unfortunately.

The proportions of Hawkins plesiosaurs are not exact to fossil data, a fact especially obvious for "P." macrocephalus, which lacks its characteristically large skull. They capture the main characteristics of plesiosaurians however, with “P”. macrocephalus - undersized head aside - being especially pleasing with its robust, deep tail and powerful-looking shoulders (see this blog post for a run down on plesiosaurian life appearance). These attributes make it the most ‘modern looking’ of all three sculptures. Additional fine details include the eyes being angled upwards, and might the obvious teeth reflect a suggestion that they were permanently visible? I’m not sure where we are regarding ideas about plesiosaurian facial tissues, but it’s not unreasonable to assume liplessness, or at least lipless regions, for some or most plesiosaurians (and it seems near certain for some taxa, like pliosaurids). The presence of smooth skin does not entirely align with what we now know of plesiosaurian anatomy, but it’s not a bad inference given that their scales were actually tiny - just millimetres across (Frey et al. 2017). It’s difficult to imagine how the materials available to Hawkins and his team could have been crafted to show such fine detail even if such data was available to them.

There are several major differences between Hawkinsian plesiosaurians and our modern takes. The most obvious of these is their thin, highly flexed necks, which recall those of long-necked birds or snakes even down the obvious neck/skull junction. It is highly unlikely that plesiosaurians could bend their necks as depicted at Crystal Palace, nor do their neck vertebrae imply a light covering of musculature (Noè et al. 2017). Today, we assume plesiosaurians were capable of a reasonable degree of neck flexion, but perhaps only to the extent of forming broad arcs, not multiple tight curves. The Crystal Palace plesiosaurians also have slender, flexible bodies, more like those of lizards (to which they were often compared in early palaeontological literature) than their actual stiffened, barrel-shaped torsos. The P. dolichodeirus and Thalassiodracon hawkinsi models are particularly afflicted with this issue, and their long, flexible tails accentuate their lithe forms further. We can perhaps rationalise this by the holotypes of these plesiosaurs having relatively narrow torsos (a taphonomic influence is probable in both cases) as well as the prevalent early-19th century idea that plesiosaurians were more closely related to lizards than other marine reptiles ("Plesiosaurus", roughly translated, means "allied to lizards" - Owen 1854). Unbeknown to Hawkins and Owen, we would eventually find soft-tissue outlines of plesiosaurians showing substantial soft-tissue around their tails, perhaps reflecting hindlimb musculature (assuming they anchored some major leg muscles on their tails, as is the case for most reptiles) as well as body-contouring fatty tissues (Frey et al. 2017). Their flippers were also augmented with soft-tissue expansions, something Owen knew about for ichthyosaurs, but would not be apparent for plesiosaurians until the late 19th century.

George Scharf's illustration of "P. macrocepahlus", featured in Owen (1840b). The skull is obviously very large in this species, but Hawkins did not capture this in his model.

Further contrast with modern plesiosaur reconstrusions concerns the attitude and flexion of the statues' flippers. They are shown as having ample fore and aft motion as well as obvious elbow and knee joints. This was pretty typical of plesiosaurian art in the 19th century, and probably reflected Victorian assumptions of a turtle-like locomotory capacity in these reptiles. Today, we regard plesiosaur flippers as having more limited flexion. They had no joints along their length, and forward and backward motions were the most limiting axes of their shoulder and hip articulations (e.g. Carpenter et al. 2010; Liu et al. 2015). These properties have bearing on another difference: the portrayal of all three plesiosaurians as crawling in shallow water. It’s near certain that plesiosaurians would struggle to move around out of water (see this blog post for details), and evidence that they gave live birth negates the need for land-based behaviour (O'Keefe and Chiappe 2011). But for Hawkins, Owen and other 19th century scholars, who still regarded even ichthyosaurs as using land-based reproduction, plesiosaurians crawling around on land would have seemed reasonable.

Plesiosaurus dolichodeirus as we know it today: not a million miles off the Crystal Palace reconstruction, but significantly different in several aspects.

That's all for now, but we'll soon move on to teleosaurids, pterosaurs and - the star attractions: dinosaurs! Remember to check out the Friends of Crystal Palace Dinosaurswebsite if you haven't already, and please consider getting involved with supporting these fantastic, significant models if you can.

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References

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• Benton, M. J., & Gower, D. J. (1997). Richard Owen's giant Triassic frogs: archosaurs from the Middle Triassic of England. Journal of Vertebrate Paleontology, 17(1), 74-88.
• Carpenter, K., Sanders, F., Reed, B., Reed, J., & Larson, P. (2010). Plesiosaur swimming as interpreted from skeletal analysis and experimental results. Transactions of the Kansas Academy of Science, 113(1/2), 1-35.
• Damiani, R. J. (2001). A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli). Zoological Journal of the Linnean Society, 133(4), 379-482.
• Doyle, P., & Robinson, E. (1993). The Victorian ‘Geological Illustrations’ of Crystal Palace Park. Proceedings of the Geologists' Association, 104(3), 181-194.
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• Hawkins, B. W. (1854). On Visual Education as Applied to Geology: Illustrated by Diagrams and Models of the Geological Restorations at the Crystal Palace. W. Trounce
• Kammerer, C. F., Angielczyk, K. D., & Fröbisch, J. (2011). A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy. Journal of Vertebrate Paleontology, 31(sup1), 1-158.
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• McCarthy, S., & Gilbert, M. (1994). The Crystal Palace dinosaurs: The story of the world's first prehistoric sculptures. Crystal Palace Foundation.
• Moser, M., & Schoch, R. (2007). Revision of the type material and nomenclature of Mastodonsaurus giganteus (Jaeger) (Temnospondyli) from the Middle Triassic of Germany. Palaeontology, 50(5), 1245-1266.
• Noè, L. F., Taylor, M. A., & Gómez-Pérez, M. (2017). An integrated approach to understanding the role of the long neck in plesiosaurs. Acta Palaeontologica Polonica, 62(1), 137-162.
• O’Keefe, F. R., & Chiappe, L. M. (2011). Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia). Science, 333(6044), 870-873.
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• Owen, R. (1841b). XIX.—A Description of some of the Soft Parts, with the Integument, of the Hind-fin of the Ichthyosaurus, indicating the Shape of the Fin when recent. Transactions of the Geological Society of London, 2(1), 199-201.
• Owen, R. (1842). XXXII.—Description of parts of the Skeleton and Teeth of five species of the Genus Labyrinthodon (Lab. leptognathus, Lab. pachygnathus, and Lab. ventricosus, from the Coton-end and Cubbington Quarries of the Lower Warwick Sandstone; Lab. Jægeri, from Guy’s Cliff, Warwick; and Lab. scutulatus, from Leamington); with remarks on the probable identity of the Cheirotherium with this genus of extinct Batrachians. Transactions of the geological Society of London, 2(2), 515-543.
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• Owen, R. (1854). Geology and inhabitants of the ancient world. Crystal palace library.
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It's time to continue our palaeoartistic discussion of the famous 1850s Crystal Palace prehistoric animal sculptures. As you'll know if you've read part 1 of this series, I've been supplying artwork and palaeoart notes to the Friends of Crystal Palace Dinosaurscharity for their new 'about the statues' web pages. What started as a small project has ballooned into several weeks of illustration, research and writing based around these charming and fascinating early palaeoartworks, culminating in this series of blog posts. As before, we'll be reviewing the models in roughly sequential order. Previously, we looked at the Dicynodon, "Labyrinthodon" and marine reptiles, and today we'll be covering the Jurassic Teleosaurus, the Jurassic and Cretaceous pterosaurs, and the Late Cretaceous Mosasaurus. Those familiar with the Crystal Palace prehistoric menagerie will recognise a dinosaur-shaped hole in that line-up but, have no fear: we'll be covering them next time, and then the mammals after that.

As before, I want to point out that the following notes are expanded and referenced versions of content I've provided for the Friends of Crystal Palace website, and readers are encouraged to check out those pages to supplement the dedicated palaeoartistic assessment provided here. Also, while I don't want to labour the need for increased interest and investment into the Crystal Palace sculptures - there's lots of that in the introduction to part 1 - I want to remind readers that these models, now approaching 170 years old, need a lot of care and maintenance. Efforts to restore the models are underway, and you can help by donating money or volunteering your time to keep the site maintained.

Teleosaurus

The Crystal Palace Teleosaurus sculptures as seen from the Secondary Island. Both Teleosaurus have been restored recently and look very handsome, the aim is to get all the models looking this good in the next few years. Note that these models are meant to be surrounded by water, but last year the entire site was covered in lush vegetation. Photo from 2018.

Two Teleosaurus bask on the banks of the Secondary Island as part of the Jurassic Oolite scene that also includes Megalosaurus and (before they went missing) small pterosaurs. As superficially crocodylian-like animals, Teleosaurus was perhaps the most straightforward fossil reptile for Hawkins to restore. The two Teleosaurus models are, in terms of detailing, some of the finest reptile restorations in the Crystal Palace arrangement. The general proportions of Teleosaurus are captured correctly with its short limbs, long body and narrow, gracile jaws, and their depiction as basking on a shoreline is consistent with predictions of teleosaurid habits. Teleosaurids were part of a marine radiation of crocodylian-line reptiles but they still bore limbs instead of flippers, and they lacked well-developed tail fins. In not being as specialised for an open water existence as subsequent marine crocodylomorphs, it’s entirely possible, maybe even likely, that teleosaurids returned to shore for rest and procreation.

The rarely seen posterior end of the remaining complete Chalk Pterodactylus. Note the deep chest and pelvic region, bird-like limb posture and blunt, deep tail. This is the body of a bird, not a pterosaur. The triangular structure on the left of the image is the wing of the neighbouring pterosaur. Photo from 2018.

Hawkins' Oolite pterosaurs were based on scrappy material once referred to "Pterodactylus bucklandi", which later became subsumed into the genus "Rhamphocephalus". We now know that "Rhamphocephalus"has little taxonomic utility, being based on teleosaurid fossils and containing no valid pterosaur species. The Oolite species Klobiodon rochei is a rhamphorhynchid, the sort of animal that the "Pterodactylus bucklandi" material likely represents.

The Crystal Palace Iguanodon and Hylaeosaurus as illustrated in Matthew Digby Wyatt's 1854 Views of the Crystal Palace and Park, Sydenham. These Iguanodon are surely some of the most famous Victorian palaeoart in the world, and probably some of my favourite palaeoartworks of all.

Welcome to part three of our discussion of the science behind the Crystal Palace prehistoric animal sculptures. As you'll know if you've read the previous entries in this series (part 1, part 2), these articles are the result of my working with the Friends of Crystal Palace Dinosaurscharity to produce artwork and palaeoart notes for their new 'about the statues' web pages. Please check out part 1 for additional context about the work of the FOCPD and the need for continued care and maintenance of the Crystal Palace sculptures. Restoration work on the models continues, and you can help by donating money or volunteering your time to keep the site maintained.
Having now covered the bulk of the Palaeozoic and Mesozoic animals (Dicynodon, "Labyrinthodon", the marine reptiles, Teleosaurus, pterosaurs, and Mosasaurus), it's time to focus on what are, for many, the main attraction: the dinosaurs. The four dinosaur statues of the Secondary Island are the largest models of the entire display and their elevation above the surrounding landscape makes them imposing, conspicuous figures even from afar. They are undeniably the most famous and spectacular components of the Crystal Palace menagerie, but also routinely mocked and ridiculed for being so scientifically dated. Such derision is entirely unfair as it ignores how much of dinosaur anatomy they accurately recorded, how cutting edge they were in the 1850s, and how progressive Benjamin Waterhouse Hawkins was in his approach to their reconstruction. Though far removed from how we imagine dinosaurs today, Hawkins captured the foundation of what makes dinosaurs unique and charismatic in his takes on the Jurassic theropod Megalosaurus and two Cretaceous, Wealden species: Iguanodon and Hylaeosaurus.

As important milestones in early depictions of prehistoric animals, much has been said about the history and science informing the Crystal Palace dinosaurs. It must be said that a lot of the most familiar and popular tales about the sculptures are oversimplified or simply untrue. An example is the framing of the dinosaur sculptures within the context of the Richard Owen vs. Gideon Mantell rivalry, whereby Owen uses the statues to score some final points against Mantell by imposing his vision of Dinosauria on the Victorian public (e.g. Dean 1999; Torrens 2012). In actuality, Mantell was asked to be the consultant for the Crystal Palace prehistoric models before Owen, but he declined the offer on grounds of the models not being educational enough and, probably, his declining health (he died in 1852, before construction of the models was finished). Owen would attempt to re-write these affairs to position himself as first choice as technical advisor to the project, as well as the man who suggested to hire Hawkins (Dawson 2016).

Hylaeosaurus better side, as seen in 2018. Its face is all but invisible from public paths around the Geological Court and it's only by visiting the Secondary Island itself that you can get a good look at the whole animal. Note the presence of a nasal boss and enlarged, thickened scales over the neurocranium, recalling certain iguana species.

Owen’s well-documented disinterest in the Crystal Palace models (Secord 2004; Dawon 2016) is also inconsistent with him bending the models to his unique vision of Dinosauria. Hawkins did not always follow Owen's latest ideas in his Crystal Palace work: in some places the dinosaur models reflect older Owenian theory, and in others they are very Mantellian in form. Owen was unaware of important decisions being made about the appearance of the dinosaurs (Secord 2004) and he recorded several dissenting opinions about their anatomy in his 1854 Crystal Palace guidebook, including objections to the Iguanodon nose horn and a comment about the Hylaeosaurus armour being conjecturally restored. History suggests that Owen was not invested enough in the models to be using them in academic politics against Mantell's legacy.

The Crystal Palace dinosaurs were far from the first efforts to restore dinosaur form, and they represented significant advances over earlier efforts. John Martin's 1837 The country of the Iguanodon is more typical of early dinosaur art, depicting Iguanodon and Megalosaurus as whale-sized lizards. The Crystal Palace dinosaurs were more realistically sized and included more characteristic anatomy, including strong, upright limbs, and taxon-specific features, such as beaks and osteoderms. Hawkins' reconstructions were definitely 'dinosaurs v. 2.0', not just life-sized versions of art that came before. Image in public domain, borrowed from Wikimedia.

Although a substantial haul of dinosaur bones had been amassed from southern Britain by the 1850s, no dinosaur taxa were well-known at this time (despite Owen’s PR-friendly 1854 statement that all the sculptures were based on species for which “the entire, or nearly entire, skeleton had been exhumed in a fossil state”). Accordingly, the dinosaurs were constructed using Owen's basic dinosaur body plan (i.e. quadrupedal reptiles with mammal-like features, including proportionally large and erect limbs, strong, weight-bearing hips and terrestrial habits) and augmented with features either suggested by fossil material or else consistent with their predicted anatomy and lifestyles (Owen 1854). The results are far from the mark as goes modern interpretations of Iguanodon, Megalosaurus or Hylaeosaurus, but they are reasonable imaginings of dinosaurs given the material known to Hawkins at that time.

Although often mocked for their depiction of now archaic ideas, the models were actually a significant advance over earlier depictions of dinosaurs as whale-sized lizards. It could be argued that the models did not present the most progressive view of dinosaurs available in the early 1850s as they ignored Mantell’s insightful considerations of Iguanodon proportions and pose (Mantell 1848, 1851, see below) but, even so, each model references ideas about dinosaur anatomy that were, at the time, very modern and cutting-edge. Hawkins’ dinosaur sculptures are an excellent record of that short period in history when the unique and defining aspects of dinosaurs had been recognised, but our fossil data were still too incomplete to reveal their overall forms. They capture, on grandiose scale, an important intellectual milestone in the realisation of what dinosaurs were, and are a monument to the ingenuity of early palaeontologists.

Megalosaurus

Megalosaurus as seen in 2013 - more or less as it looks today, but the surrounding vegetation is lower so you can see the full extent of the powerfully muscled hindlimbs. Not visible in this photo is a long crack which runs down the length of the model on the right side of the neck and torso: these sculptures weigh several tonnes apiece, and putting all that weight on four limbs takes its toll.

Hawkins’ Megalosaurus is specifically meant to represent M. bucklandi, a species known to him from a jaw bone and teeth, a few vertebrae, pelvic bones and some hindlimb material. It is a fairly faithful representation of Owen’s vision of Megalosaurus, which we also have documented in his 1854 guidebook (below). This famous illustration, which blends life restoration with skeletal reconstruction, is the only instance of Owen providing us with his vision of a dinosaur to compare with Hawkins. Owen’s drawing - which is also one of the oldest known skeletal diagrams of a dinosaur (see Scott Hartman’s excellent History of Skeletal Drawings) - does not sugarcoat the volume of material known for Megalosaurus in the early 1850s and instead (perhaps inadvertently) showing us the huge gulfs of dinosaur anatomy that Hawkins had to restore from just a handful of remains.

Owen's skeletal restoration of Megalosaurus bucklandi from his 1854 Crystal Palace guidebook, a significant illustration in the development of skeletal diagrams of fossil animals and the only hint in his guidebook as to what was truly known of the species restored by Hawkins. The Crystal Palace sculpture is pretty faithful to this, but note the lack of the shoulder hump and smaller head.

Curiously, Owen did not include the full 1854 inventory of Megalosaurus fossils in his drawing or text, omitting some potentially significant vertebrae from the Wealden that had been referred to this taxon (see below). This suggests that Hawkins’ Megalosaurus was based entirely on Jurassic material that we still regard as M. bucklandi, and that it narrowly escaped being a chimaera of several theropod taxa. Even in the 1850s Megalosaurus was becoming a wastebasket of carnivorous dinosaur material that would eventually contain dozens of species. Today M. bucklandi is regarded as the only species of Megalosaurus (Benson 2010), and while its exact proportions remain unknown, it is imagined as a large-headed creature with a robust, three-fingered hand, and most likely similar to Torvosaurus in general form. It was probably 6-7 m long - mid-sized for a theropod dinosaur, but large for one from the Middle Jurassic.

Although working from little material, Hawkins did not simply take Owen's dinosaur concept and bolt some sharp teeth into the jaws. Rather, his Megalosaurus has several hallmarks of predatory species that reflect close observation of living animals. The limbs, for instance, are not pillar-like as in the Iguanodon but have flexed joints and bulging musculature. This pose recalls the limbs of rhinos - relatively fast, sprightly large animals - more than the columnar-limbs of slower paced giants, like elephants. The body is trim and streamlined, tapering from the muscular shoulders towards the hips, and also lacks an expansive gut. Hawkins would have known that carnivorous animals have smaller, shorter guts than herbivores, and he probably modelled his Megalosaurus with this in mind. The massive head (some five feet in length, probably based an older Owen estimate (1842, 1854), and not reflecting the revised 2' 6" length published by Owen in 1856) is held in place with deep neck muscles anchoring to an enlarged shoulder skeleton. Hawkins was clearly referening large-headed mammalian herbivores such as bovids and rhinos here, and his transference of their head-supporting apparatus to a predatory reptile shows his resourceful approach to reconstructing these poorly known animals. The result is a creature that looks undeniably powerful and predatory, a mix of bear, buffalo and crocodile. It’s difficult not to imagine the model as eying the adjacent Iguanodon as a potential meal.

Megalosaurus bucklandi as we understand it today: a large-ish theropod that roamed Jurassic Britain, posing in ways that loosely homage Charles Knight's work.

Hawkins'Megalosaurus is restored with mouth slightly ajar, and it’s clear from both the model and associated Hawkins’ artwork that the teeth are modelled on those of crocodylians - in other words, they would be visible even when the mouth was closed. Today, the subject of dental exposure in dinosaurs and other fossil forms is a hot topic among palaeoartists, but we can view Hawkins’ take as being in line with general ideas of dinosaur palaeobiology c. 1850. The situation of dinosaur teeth in sockets was identified early on as being more crocodylian- than lizard-like, and it was not unreasonable for Hawkins to extrapolate this to a full crocodylian-grade jaw. Curiously, his other dinosaur models have lips: perhaps he felt that their more lizard-like teeth warranted more lizard-like facial anatomy?

Having mentioned the shoulder hump, it would be remiss not to outline the interesting history of this structure. Darren Naish (2010) proposed that the shoulder hump of Megalosaurus was based on Altispinax dunkeri, three Wealden theropod vertebrae with tall neural spines known to Owen in the 1850s. Owen (1855, 1856) regarded these as the shoulder vertebrae of M. bucklandi and remarked that their tall spines must have anchored powerful, head-supporting muscles used to aid Megalosaurus in pulling apart carcasses. Circumstance suggests that Owen must have given Hawkins advance notice of this but... surprisingly no - other data suggests otherwise. Secord (2004) reports that Owen actually had no idea about the Megalosaurus shoulder hump until the models were completed and installed, and the absence of either Wealden bones or an obvious shoulder hump in Owen's 1854 illustration confirms that he was not envisaging Megalosaurus in such a guise in the early 1850s. Secord also reports an ambivalent 1855 newspaper quote from Owen regarding the accuracy of the shoulder hump. When asked if the hump was a genuine feature of Megalosaurus, Owen replied that "no one could say that the bump was not there”, and he once again did not mention Altispinax despite the kudos they would have brought to the model and his skills as a consultant. Post-1854 boasting from Hawkins confirms the fact that Altispinax was not referenced in the Crystal Palace Megalosaurus, as he used the discovery of these 'shoulder hump' bones as evidence of his sharp skills for anatomical prediction (Secord 2004). It's perhaps significant that Owen presented older Megalosaurus size predictions in his 1854 guidebook, possibly indicating that his Crystal Palace consultancy pre-dated the analysis he presented in his 1855 Megalosaurus monograph, or that he was keeping his later work under wraps.

The Witton-Macleans and Hawkins'Megalosaurs, in 2018. Though small compared to estimates of dinosaur size from the early 1800s, the Crystal Palace dinosaurs are still big, imposing artworks. It occurs to me that this might be the first picture of me and the Disacknowledgement on this blog, which I've been writing since 2012. Well, we don't want to rush things, right?

The skin texture of Hawkins’ Megalosaurus is also interesting. Rather than obviously scaly, as per his other dinosaurs, the skin has deep fissures and wrinkles that recall elephant skin. The decision to not depict individual scales was actually quite precedent, as the eventual discovery of dinosaur scales would reveal their surprisingly small nature (typically less than a centimetre across). Alas, the thought process behind Hawkins’ decision to use this skin texture is not clear, there being no mention of wrinkled Megalosaurus skin in Owen’s guidebook or in other literature of the time. A generous interpretation could be of Hawkins having an intuitive sense that dinosaurs might be ‘more than just reptiles’, a fact later vindicated by their skeletal proportions and the discovery of diverse skin types and feathering. More cynically, perhaps he wanted a skin type to distinguish the Megalosaurus from the other dinosaurs? Or maybe he just ran out of time to complete the model with the detailed scaly finish used on Iguanodon and Hylaeosaurus?

Hylaeosaurus

The most overlooked dinosaur of the Crystal Palace trio is Hylaeosaurus armatus: the first ankylosaur known to science. It’s easy to ignore this species even when visiting the Geological Court in person as, although prominently placed between the Megalosaurus and Iguanodon, the sculpture’s face is not visible from the public paths around the Secondary Island. Instead, we can only see the hindquarters and left side. This is great for showing off the armoured back, but undeniably leaves a lesser impression on visitors - especially as it competes for attention with very imposing and charismatic statues either side.

Hawkins' take on Hylaeosaurus armatus in 2018, seen as standing on the Secondary Island and not from the path on the Crystal Palace 'mainland'. Note the armoured back (not just the spines, but also the prominent tubercles) and iguana-like face. The head of this model is a fibreglass replica, the original having fallen off and put on display elsewhere in the park.

I recall an explanation for the peculiar orientation of Hylaeosaurus being that cranial material was unknown to science at this time, so the model was positioned facing away from the public to obscure its face. I can’t remember where I learned this, but it’s incorrect in any case. Today, Hylaeosaurus is chiefly represented by a slab containing a portion of skull, several neck and shoulder vertebrae, elements of the pectoral girdle and the large spike-like scutes that covered its skin (Barrett and Maidment 2011). But in the early 1800s Hylaeosaurus inventories were much broader, also containing referred jaws, teeth, limb bones, and hip and tail elements (Owen 1842). This rendered Hylaeosaurus c. 1854 comparable to Megalosaurus in representation, so lack of anatomical reference does not account for Hawkins hiding its face. Modern takes on Owen’s additional Hylaeosaurus specimens sees his referred jaw belonging to a stegosaur (the only one known from the British Wealden) and the teeth pertaining to a sauropod (Barrett and Maidment 2011). The other elements probably represent indeterminate ankylosaur bones. Accordingly, Hawkins’ Hylaeosaurus is the most chimeric of all the Crystal Palace dinosaurs, mixing elements from not just several related species, but several major dinosaur groups.

Hawkins’ restoration of the Hylaeosaurus armour was very reasonable given the material he was working with. Two types of osteoderm were recognised for Hylaeosaurus in the 1830s and 40s: large spikes, and low elliptical structures that sometimes bore tubercles at their summit. Both feature prominently on the dorsal surface of Hawkins' sculpture, covering the braincase, shoulders, back, haunches and tail. The spines are arranged in a single row along the midline and are flanked either side by extensive sheets of smaller, elliptical scutes. Whether Hylaeosaurus had one or more rows of spiny osteoderms was the subject of discussion among early palaeontologists, and ultimately Hawkins decided to side with Mantell, not Owen, in depicting a single row. Mantell (1833) interpreted the Hylaeosaurus spikes as being from a spiny midline fringe, akin to those of iguanine lizards, while Owen initially had reservations about them being osteoderms at all. Writing in 1841, Owen stated that he did not disagree with Mantell's idea of them being armour, but he also thought that the 'spines' could be displaced abdominal ribs. By 1854 Owen conceded that Mantell’s identification of the structures as dermal spines was accurate, but he also remarked that Hawkins’ arrangement of the spines was conjectural. A few years later Owen returned to the issue of the spines again, and provided insightful reasoning for the spines being arranged in two parallel rows (Owen 1858). The evolution of Owen’s ideas saw him creeping closer to the reality of ankylosaur life appearance and, today, we know that he was close to the truth: ankylosaurs were indeed covered with multiple rows of scutes, spines and spikes. Alas, this realisation came too late to be incorporated into Hawkins’ models.

The Crystal Palace Hylaeosaurus is probably the most lizard-like of the three featured dinosaur species with its low, crouched pose, large feet and entirely scaly, lipped face. Aspects of the skin recall heavyset, tough-skinned iguanines such as the Galapogos genera Amblyrhynchus or Conolophus (viz. low tubercles and hornlets around the back of the head, a scaly nasal prominence, polygonal scales on the body and limbs), which accords with Mantell’s (1833) referencing of iguanas as a model for the Hylaeosaurus spiny fringe. Though sporting some very fine facial features (though lacking the beak of true ankylosaurs), Hylaeosaurus is Hawkins’ only dinosaur sculpture without visible teeth*. Given that Owen (1842, 1854) had referred teeth to this species, and that virtually all the other non-mammal statues have exposed dentition, this omission is peculiar. Perhaps, if the sculpture was always planned to face away from visitors, Hawkins decided that sculpting an open mouth with individually placed teeth was unnecessary.

*As an aside, it's worth specifying that the Crystal Palace dinosaur models have metal teeth inserted into their mouths, while the other models have teeth molded from concrete. The dinosaur's metal teeth were stolen as souvenirs by Victorian visitors (Secord 2004)!

Hylaeosaurus remains a poorly known animal even today, but it probably looked a little like the more familiar Polacanthus, another Wealden species shown in this 2015 illustration. In some repsects the Crystal Palace version is not a million miles off this.

Hawkins’ Hylaeosaurus is his most authentic dinosaur with respect to our modern understanding, accurately capturing an ankylosaur as a low-slung quadruped with a short neck, long tail and an armoured back. Unlike the Crystal Palace Megalosaurus and Iguanodon, which were soon embarrassed by the discovery of remains indicating entirely different body forms, the depiction of Hylaeosaurus as a heavyset quadruped was vindicated in 1858 with the discovery of Scelidosaurus harrisonii in Jurassic deposits of the southern UK. This specimen - the first near complete dinosaur skeleton ever found - matched many aspects of the Crystal Palace Hylaeosaurus as well as Owen’s general ideas about dinosaur form. However, despite describing Scelidosaurus in detail, Owen (1863) did not capitalise on this opportunity for personal vindication. David Norman (2000) ascribes this to Owen being ever busier from the late 1850s onwards, taking on prominent roles in establishing the British Museum of Natural History (today known as London's Natural History Museum), taking part in numerous debates about evolution and natural selection, as well as maintaining an enviable output of papers, books and monographs. I wonder if Owen’s general disinterest in the Crystal Palace animals has relevance here as well, as might the failure of the wider Crystal Palace Park project. Within just a few years of opening the Crystal Palace Company was struggling to recoup the great expense of their ambitious development and the primary business of Crystal Palace Park had shifted from education and enlightenment to festival, sport and spectacle (Secord 2004). While being involved with Crystal Palace evidently did not harm Owen’s career, perhaps he could not, or dare not, wear his association to the failing project with pride. Hawkins, whom we may also have expected to use Scelidosaurus to promote his anatomical insights, was by this point busy working on other dinosaur material in the United States. Both men seemed to have moved on surprisingly quickly from what would be, among the public at least, some of their best known and longest-standing work.

Iguanodon

Hawkins'Iguanodon: exemplar palaeoart from the Victorian age, seen in 2018. This photo is taken from immediately next to the Hylaeosaurus, allowing us to see the reposed model in anterior aspect: look those excellently modelled shoulders and neck. Remember that these things were constructed using materials typically employed for building houses, not fine sculptures: the detailing is superb.

Probably the most completely known dinosaur for Hawkins was Iguanodon, which might explain why this dinosaur was captured in two models rather than just one. The Crystal Palace Iguanodon are likely the most famous Victorian dinosaur restorations in the world but, today, it’s hard to say exactly what animals they represent. Until relatively recently Iguanodon was a wastebasket for iguanodont material from the southern UK, a long-standing problem deeply rooted in Iguanodon taxonomic history. Several distinct taxa have now been identified among the British "Iguanodon"material, and much needed taxonomic revisions anchored the name Iguanodon to I. bernissartensis, the famous species chiefly known from Belgian skeletons (see Norman 2013 for a review). I. bernissartensis is known from the UK, but it's relatively rare and geologically younger than most of the "Iguanodon" material used by Mantell, Owen and Hawkins to conceptualise Iguanodon in the early 1800s. An upshot of this is that the Crystal Palace Iguanodon were informed by fossils that we no longer recognise as Iguanodon today.

We do not have a definitive list of specimens examined for the Iguanodon models, but Owen (1854) and Hawkins (1854) allude to three important reference specimens. Firstly, Owen (1854) specifically identifies the models as being "I. mantelli", one of two names applied to the original set of Iguanodon teeth described by Mantell in the 1820s. These teeth are no longer considered diagnostic for any species, but are a close match for those from the Valanginian iguanodont Barilium dawsoni (Norman 2011). Many anatomical and proportional details were taken from a second specimen, the famous “Mantel-piece”, which is today regarded as Mantellisaurus atherfieldensis (though not incontrovertibly - see Norman 2013). Thirdly, Hawkins (1854) notes that a large iguanodont specimen (below) from Horsham was used to establish the size of the models. This specimen has been all but forgotten in modern literature despite earning the local nickname of the “Great Horsham Iguanodon” and being referenced as an exceptionally large specimen by Owen (1855). Details of the Horsham specimen suggest it is almost certainly another specimen of Barilium, being sourced from the Hastings Beds (deposits yet to yield true Iguanodon fossils, but definitely containing Barilium) and having a scapula bearing characteristic features of this taxon (Norman 2011). Note that none of these specimens contain a thumb spike - the source of the famous nose horn - so this must have stemmed from yet more reference material. Hawkins might have based the nose horns on the large thumb spikes published by Mantell in 1827 and, if so, they represent another iguanodont species for our list, Hypselospinus fittoni (Norman 2015). That gives us at least two, and possibly three, iguanodont species represented in the Crystal Palace "Iguanodon" sculptures, not one of which is actually Iguanodon as we define it today. We cannot rule out Hawkins examining some true Iguanodon material in his research for the models, but if he did, they were not significant enough to warrant mention in any known literature.

Rib (left) and portion of dorsal scapula (right) of the "Great Horsham Iguanodon", as seen on display in Horsham Museum and Art Gallery in 2019. There's more material to this specimen, including a toe bone, not on show here. This largely forgotten specimen which was pivotal in establishing a realistic size estimate for Iguanodon (Owen 1855). Notice how flared the scapular termination is: this is characteristic of material referred to Barilium dawsoni, and quite different from the scapula of Iguanodon (Norman 2011).

Hawkins’ Iguanodon are basically Owenian in form, but he conflicted with Owen by giving his restorations a Mantellian nose horn. Owen (1854, 1855) was strongly opposed to Iguanodon having such a structure, devoting several monograph pages to dismantling this identification and correctly identifying it as a spike-like claw in 1855. Owen’s observations on the ‘nose horn’ were entirely sound, but Hawkins, presumably like Mantell, was probably inspired by the presence of nose horns in many iguana species. Iguanas may have informed the models in other regards as well, including the large tympanic membranes (their conspicuous ‘ears’), dewlaps, midline body and tail spines, and details of their scalation. The edentulous beak and blunt claws are deviations from iguanas and were correctly restored for Iguanodon, these presumably being based on lower jaws and digit bones recovered during the early 1800s. Here, Hawkins was more accurate than Mantell, who’s final conceptualisation of Iguanodon included prehensile lips and a protruding tongue (Mantell 1851). The grasping hand of the reposed Iguanodon could be a Mantellian nod however, reflecting his proposal that Iguanodon used its forelimbs to grasp vegetation (Mantell 1849, 1851; Dawson 2016). If so, it's noteworthy that Hawkins did not follow Mantell's observation that the forelimbs were relatively slender, instead sticking to the convention of Iguanodon being a columar-limbed quadruped. Hawkins’ construction of Iguanodon at just over 10 m long was very ‘modern’ for the time, contrasting to earlier calculations of its length where scant bones were interpreted as belonging to creatures many tens of metres long (Mantell 1851; Owen 1854, 1855).

It should be observed how lifelike and detailed Hawkins Iguanodon are. More than any other reptile sculpture in the Geological Court, Hawkins Iguanodon give the impression of capturing real animals. Most of the other reptiles are posed fairly functionally: they lie or stand in ways that allow us to see their form clearly. But Hawkins’ Iguanodon have a touch more dynamism. The reposed individual looks relaxed with its subtly spreading belly and cycad-pawing hand, while the animal above and behind it looks vigiliant and alert. Their composition implies real behaviours and personalities in these anatomically fictional, but entirely believable restorations. Coupled with their enormous size, these aspects make them (for me, at any rate) the most spectacular models of the entire display.

What does the inside of a Crystal Palace dinosaur look like, you ask? The standing models have holes in the bottom (presumably for drainage and maintenance access) which allow you to see inside, and they look like this. Here, we're seeing the interior view of the standing Iguanodon sculpture, with light shining through the open mouth. I'm not sure how much of this is original and how much represents conservation work, but it's evident that the bulk of the models are Victorian bricks, motar, concrete, and supporting metal struts. These old-school materials are one reason that the models are so fragile, why they need dedicated upkeep, and why we shouldn't be climbing and sitting on them (for shame, people in that photo!).

Just over a decade after the Crystal Palace dinosaurs were installed, discoveries of another ornithopod, Hadrosaurus, in New Jersey, USA began to erode the credibility of not only Hawkins’ Iguanodon but the entire Crystal Palace prehistoric project. Hadrosaurus showed dinosaur anatomy as very different to what was being imagined in Victorian Britain. Suddenly, the Crystal Palace dinosaurs looked, at best, like naive and over-eager attempts to interpret fossil bones or, at worst, like products of arrogant Victorians assuming they could command the anatomy of long dead species from nothing like complete skeletal material. Perhaps the truth is somewhere between. Later, fossil discoveries in Belgium in 1878 would essentially give us our modern take on Iguanodon anatomy and, in doing so, took away any lingering scientific credibility from Hawkins’ portrayals. A suite of Iguanodon skeletons recovered from a Bernissart coal mine revealed an animal with powerful hindlimbs; relatively slender, shorter forelimbs equipped with large thumb spikes; a beaked, horse-like head; and a long, deep tail. Initially restored as a kangaroo-like biped, Iguanodon would eventually be realised as we know it today: a horizontally-backed animal that could alternate between bipedal and quadrupedal gaits. Iguanodon is the only Crystal Palace dinosaur species now known from complete skeletons, making it a most poignant indicator of how far palaeontological science has moved from the era of Hawkins and Owen.

Iguanodon bernissartensis as we picture it today, some still standing, some still lying down.

We've got one more stop on our tour of the Crystal Palace sculptures: the mammals. These often overlooked parts of the Geological Court contain some of the most interesting and, to some extent, tragic portions of the Crystal Palace palaeoart project. Come back soon for the conclusion to our look at these Victorian palaeoartworks, and don't forget to check out the Friends of Crystal Palace Dinosaurs, who're actively striving to get these fine artworks the recognition and conservation they deserve.

Enjoy monthly insights into palaeoart, fossil animal biology and occasional reviews of palaeo media? Support this blog for $1 a month and get free stuff!

This blog is sponsored through Patreon, the site where you can help online content creators make a living. If you enjoy my content, please consider donating $1 a month to help fund my work. $1 might seem a meaningless amount, but if every reader pitched that amount I could work on these articles and their artwork full time. In return, you'll get access to my exclusive Patreon content: regular updates on upcoming books, papers, painting and exhibitions. Plus, you get free stuff - prints, high-quality images for printing, books, competitions - as my way of thanking you for your support. As always, huge thanks to everyone who already sponsors my work!

References

• Barrett, P. M. & Maidment, S. C. R. (2011). Armoured dinosaurs. In Batten, D. J. (ed.) English Wealden Fossils. The Palaeontological Association (London), pp. 391-406.
• Benson, R. B. (2010). A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society, 158(4), 882-935.
• Dawson, G. (2016). Show me the bone: Reconstructing prehistoric monsters in nineteenth-century Britain and America. University of Chicago Press.
• Dean, D. R. (1999). Gideon Mantell and the discovery of dinosaurs. Cambridge University Press.
• Hawkins, B. W. (1854). On Visual Education As Applied to Geology, Illustrated By Diagrams and Models of the Geological Restorations at the Crystal Palace. Journal of the Society of Arts2 (78): 443-449.
• Mantell, G. (1833). Memoir on the Hylaeosaurus, a newly discovered fossil reptile from the strata of Tilgate Forest. Geology of the South East of England.
• Mantell, G. A. (1848). XIII. On the structure of the jaws and teeth of the Iguanodon. Philosophical Transactions of the Royal Society of London, (138), 183-202.
• Mantell, G. A. (1851). Petrifactions and Their Teachings: Or, A Hand-book to the Gallery of Organic Remains of the British Museum (Vol. 6). HG Bohn.
• Naish, D. (2010). Pneumaticity, the early years: Wealden Supergroup dinosaurs and the hypothesis of saurischian pneumaticity. Geological Society, London, Special Publications, 343(1), 229-236.
• Norman, D. B. (2000). Professor Richard Owen and the important but neglected dinosaur Scelidosaurus harrisonii. Historical Biology, 14(4), 235-253.
• Norman, D. B. (2011). Ornithopod dinosaurs. In Batten, D. J. (ed.) English Wealden Fossils. The Palaeontological Association (London), pp. 407-475.
• Norman, D. B. (2013). On the taxonomy and diversity of Wealden iguanodontian dinosaurs (Ornithischia: Ornithopoda). Revue de Paléobiologie, 32(2), 385-404.
• Norman, D. B. (2015). On the history, osteology, and systematic position of the Wealden (Hastings group) dinosaur Hypselospinus fittoni (Iguanodontia: Styracosterna). Zoological Journal of the Linnean Society, 173(1), 92-189.
• Owen, R. (1842). Report on British fossil reptiles, part II. Report for the British Association for the Advancement of Science, Plymouth, 1841, 60-204.
• Owen, R. (1854). Geology and inhabitants of the ancient world (Vol. 8). Crystal Palace library.
• Owen, R. (1855). The fossil Reptilia of the Wealden and Purbeck Formations. Part II: Dinosauria (Iguanodon). Palaeontographical Society of London, Monograph 1854:1–54.
• Owen, R. (1856). The fossil Reptilia of the Wealden Formations. Part III, Megalosaurus bucklandi. Palaeontographical Society. Monographs, 9, 1-26.
• Owen, R. (1858). Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Part IV. Dinosauria (Hylaeosaurus). Paleontographical Society Monograph, 10, 1-26.
• Owen, R. (1863). Monographs on the British Fossil Reptilia from the Oolitic Formations. Part Second, Containing Scelidosaurus harrisonii and Pliosaurus grandis. Monographs of the Palaeontographical Society, 14(60), 1-26.
• Secord, J. A. (2004). Monsters at the crystal palace. In: de Chadarevian, S, & Hopwood, N. (eds). Models: the third dimension of science, Stanford University Press. 138-69.
• Torrens, H. S. (2012). Politics and Paleontology: Richard Owen and the Invention of Dinosaurs. In: Brett-Surman, M.K. Holtz, Jr. T. R., & Farlow, J.O. (eds). The Complete Dinosaur, second edition. Indiana University Press, Bloomington, 24-43 pp.
• Wyatt, M. D. (1854). Views of the Crystal Palace and Park, Sydenham. Day and Son.

Just a quick heads up and some steering links in this post, normal service will be resumed next month.

I recently wrote an article about the palaeoartistic monsterisation of prehistoric animals for the Popularizing Palaeontologyblog, a web offshoot of the workshop series of the same name organised by Chris Manias of Kings College London. The PopPalaeo workshops are a series of discussions and presentations by scientists, historians, artists and curators about the public face of palaeontology, and they're always fascinating and fun events.

The most recent UK workshop - held in December 2018 - focused on how palaeontology connects with wider scientific discussions about evolution, biological progress and perception of nature. Chris invited me to speak at this event and I chose to cover how many palaeoartworks deliberately 'monsterise' their subjects, using enhanced or distorted anatomy and compositional techniques to exaggerate the ferocity of their depicted species (opening slide from my talk, above). I think we're all familiar with examples of this: if not, just check out virtually any predatory dinosaur from cinema, or the dinosaur book covers at your local book shop. Monsterised palaeoart is a topic many of us have strong feelings about as it ties into nostalgia for childhood dinosaur media, our commitments to certain franchises, and our aesthetic preferences. But it's probably neither a wholly good nor wholly bad convention: there's lots to discuss about how and why we monsterise the past, as well as it's better points ("it's a PR win!") and drawbacks ("it distorts the truth about ancient life!").

Rather than reposting my essay here, you should steer your internet browsing machine to the PopPalaeo blogto read it there. While you're there, be sure to check out the rest of the PopPalaeo website, including recorded talks from each workshop (the latest set, including my monsterising talk, is here) - lots of goodness lies therein.

Coming soon: wrapping up our series on the Crystal Palace palaeoart sculptures with an in-depth look at the oft-neglected mammal island.

Enjoy monthly insights into palaeoart, fossil animal biology and occasional reviews of palaeo media? Support this blog for $1 a month and get free stuff!

This blog is sponsored through Patreon, the site where you can help online content creators make a living. If you enjoy my content, please consider donating $1 a month to help fund my work. $1 might seem a meaningless amount, but if every reader pitched that amount I could work on these articles and their artwork full time. In return, you'll get access to my exclusive Patreon content: regular updates on upcoming books, papers, painting and exhibitions. Plus, you get free stuff - prints, high-quality images for printing, books, competitions - as my way of thanking you for your support. As always, huge thanks to everyone who already sponsors my work!

An 1853 illustration of one of the Crystal Palace mammals, Palaeotherium magnum, imagined next to the plesiosaurians it would eventually share the Geological Court with. The Palaeotherium sculpture that this image is based on is now lost, just one of many misfortunes to befall the Crystal Palace mammals. From Die Gartenlaube, archived at Wikipedia.

It's time for our final visit to the prehistoric animal sculptures of Crystal Palace Park. Having toured through the Palaeozoic and Mesozoic exhibits in the last three posts (part 1, part 2, part 3), today we turn our attention to the Cenozoic section of the Geological Court, one containing exclusively mammalian palaeoart subjects. As with previous entries in this series, these words stem from writing palaeoart notes for the Friends of Crystal Palace Dinosaurscharity - please check out part 1 for additional context about their work and the ongoing need for care and maintenance of the Crystal Palace sculptures. You can help conservation efforts by donating money or volunteering your time to keep the Geological Court maintained.

At risk of being melodramatic, I find it difficult to escape a sense of tragedy when concerning myself with the Crystal Palace mammals. They are the least documented, least discussed and most suffering of the sculptures, with several bearing obvious hallmarks of neglect and low-quality repair work. Even in the 1850s they were being sidelined to make way for the more spectacular fossil reptiles, a fact all the more tragic because extinct mammals were the inspiration for having prehistoric animals at Crystal Palace in the first place (McCarthy and Gilbert 1994). Initially, Hawkins planned to restore a woolly mammoth and other large mammals but, when developing his display, his attention was drawn to the dinosaurs and fossil reptiles which would ultimately consume most exhibition space and public interest. Once located on their own 'Tertiary Island' (Doyle and Robinson 1993), the mammals are today situated on the 'mainland' component of Crystal Palace and it's hard not to view them as being a little tucked away. Although close to the reptile displays (within sight of the Mosasaurus), most of the mammals are located on a separate path to the reptilian sculptures and they are often obscured by foliage. It's quite easy to miss them on a casual walk around the park.

A sense that the mammals were being overshadowed by reptiles may explain why Hawkins wanted to expand this component of the park. He wrote to Owen in 1855 with a plan to augment his Cenozoic fauna considerably, including models of a mammoth, a bathing Deinotherium, glyptodonts, Sivatherium and extinct bison, as well as moa, dodo, turtles and snakes (Doyle 2008; Dawson 2016). This letter was dated a full month after Hawkins was no longer working for the Crystal Palace company however, who thought he had constructed enough models and would not even let him finish a half-completed mammoth sculpture. The official reason for terminating Hawkins' work was allegedly an artistic one of “less being more” (McCarthy and Gilbert 1994), but the abrupt termination of Hawkins’ project surely reflected the financial struggles of the Crystal Palace Company shortly after the park opened (Dawson 2016). It’s certainly difficult to believe that the same company who filled their park with reconstructed ancient buildings, expanded the Crystal Palace to incredible dimensions and built fountains rivalling the biggest in Europe would suddenly be concerned about artistic excess. Some idea of what Hawkins’ mammoth, Sivatherium and turtles may have looked like may be taken from his later drawings and paintings, including his 1860s poster series that borrowed heavily from his Crystal Palace designs (Rudwick 1992).

Hawkins' grand plans for the Tertiary Island, drawn on the back of a letter to Owen in 1855. He wanted it packed with Cenozoic mammals, reptiles and birds, but the Crystal Palace Company thought this was excessive (or, more likely, couldn't afford to pay for the work). From Doyle (2008).

To my knowledge, very little information survives regarding Hawkins’ construction of the four Crystal Palace mammal species. They were built and installed at the same time as the other models but were not mentioned in Owen’s (1854) Geological Court guidebook despite his interest in fossil mammals (e.g. Owen 1846). Perhaps this is further evidence of Owen’s general disinterest in the Crystal Palace project? Victorian visitors had to make do with a very brief and incomplete overview of the mammal fauna provided in the general Crystal Palace Park guide (Phillips 1854). Later versions of this book would tweak their text on the mammals to provide short, but often historically important, insights into their composition and display. So lacking is the documentation of the mammals that we're sometimes reliant on the throwaway text in these guides to tell us how many sculptures were originally installed!

From a palaeoartistic perspective, a clear distinction between Hawkins’ task with the mammal reconstructions and his more famous reptilian efforts was the availability of anatomical information. Mammalian palaeontology was considerably more advanced than studies of fossil reptiles in the early 1800s. Complete skeletons had been known for several of the Crystal Palace species for several decades, allowing scholars to describe, illustrate and restore the osteology of these animals in detail. Hawkins surely benefitted from Owen being an authority on the anatomy of mammals (e.g. Owen 1846), including the Crystal Palace species, and probably also made use of several pioneering skeletal reconstructions, muscle studies and life restorations published by Georges Cuvier. Neglected and somewhat forgotten as they are, the Crystal Palace mammals are actually pretty good takes on the form of their subject species, and clearly demonstrate Hawkins as the equal of later palaeoart masters.

Palaeotherium

The surviving Palaeotherium sculptures in their original site at Crystal Palace, photographed in 2013. These models were temporarily moved for a period in the mid-20th century, which may explain the damage to the sitting model and loss of a third, larger sculpture.

The Eocene equoid Palaeotherium was one of the first discovered fossil mammals and was studied in detail by Georges Cuvier during the early 1800s. Its entire osteology was understood from more or less the moment it was found thanks to near-complete skeletons being recovered from French gypsum deposits at the turn of the 19th century. These brought several Palaeotherium species to the attention of early palaeontologists and led to it being the subject species for some of the oldest palaeoartworks. Both its skeleton and body outline were restored by Cuvier and artists in his employ in the early 1800s (Rudwick 1992, 1997) and these images - after some initial hesitation from Cuvier - were eventually widely published in European literature. With so much data available, Hawkins probably had little difficulty restoring Palaeotherium in three dimensions for the Geological Court.

The Crystal Palace Palaeotherium have an unfortunate history. Two models survive today but photographs from 1958 (see McCarthy and Gilbert 1994), 19th century illustrations, and later editions of Crystal Palace Park Guide (Anon. 1871) indicate that a third model once existed. It was clearly larger and anatomically distinct from the surviving models, but at present no-one seems to know what happened to it - a most regrettable circumstance. It may have been relocated or destroyed when the Tertiary Island site was taken over with a small zoo in the 1950s (we know that parts of the zoo directly encroached into the space for the models - the base of the Megatherium was part of a goat enclosure, for example (see McCarthy and Gilbert 1994)) or else when the smaller mammal models were temporarily moved in the post-war period (Doyle and Robinson 1993). I hope it hasn't been destroyed and may still turn up in some neglected part of the park or emerge from someone's garage.

Two of the three Palaeotherium models photographed in 1958, printed by McCarthy and Gilbert (1994). The standing model shown here is remarkably different in form and size from the surviving Palaeotherium sculptures and almost certainly represents a different species (P. magnum?). Its whereabouts is unknown today.

The surviving Palaeotherium have not escaped misfortune either. The sitting sculpture lost its head at some point in the late 20th century and has been fitted with a replacement, but photographs show that the original head was quite different to the one it has now (compare image above with that below). The replacement is probably a replica or cast from the other surviving Palaeotherium. Both heads are very similar in the snout, ear and eye region, and the differences - the abbreviated cheek and braincase in the sitting statue - are likely results of marrying the head of the standing animal to a sitting one. The neck has also evidently been lengthened since the 1950s and the head/neck join lacks the well-executed muscle contours characteristic of Hawkins' work. It is not the only example of strange, somewhat crude, restoration work on the Crystal Palace mammals (see below).

The sitting Palaeotherium as it appears today - note the different head to the photo from 1958 above, and the slightly awkward manner in which the head replicated from the standing animal has been grafted to the neck.

Questions about lost models and restoration work are not the only uncertainties about these models. I’m not aware of any literature that identifies the Palaeotherium sculptures beyond generic level, but my assumption is that at least one of the surviving models represents P. minus. This sheep-sized species was well described and illustrated by Cuvier and others in the early 1800s, providing Hawkins with ample reference material. I'm uncertain whether both existing sculptures represent P. minus given their historic differences in head shape and other anatomies, but each was clearly distinct from the missing third model, which was significantly larger and of contrasting form. From photographs and illustrations I estimate that the missing model was about the size of a small horse, and this almost certainly labels it as P. magnum, another species that was well illustrated in literature of the early 1800s.

I see you, cryptic P. magnum, hiding in plain sight within P. H. Delamotte's 1853 illustration of Hawkins' workshop. I've long wondered what this sculpture was given that it didn't quite fit anything on display at Crystal Palace, but it's a perfect match for the missing P. magnum model - note the concave back, upright head, straight forelimbs and Gonzo-esque nose. Image modified from Wikipedia.

It’s difficult to evaluate the Palaeotherium models against the science of their day because of modifications made since their installation. Scholars of the early 19th century regarded Palaeotherium as a tapir-like animal with a short proboscis. Cuvier went as far as to suggest that some Palaeotherium species would, should we see them alive, be virtually indistinguishable from modern tapirs (Rudwick 1997). Hawkins evidently followed this suggestion with his smaller standing model, giving it a long, tapir-like face, an arched back, a podgy, creased torso recalling the Malayan tapir, and short, round ears. He opted to give the feet a more horse-like appearance however, which is appropriate to Palaeotherium limb anatomy. The sitting Palaeotherium model also has a tapir-like body, but it lacks the obvious creases of the other surviving model. Perhaps they are, indeed, meant to be different species. The previous head of this sculpture was certainly very different in being much shorter and smaller, and doesn't bear a strong resemblance to any living animal.

Stranger still is the lost model, which was far removed from a tapir-like form except for its short trunk. This large sculpture rather recalls African bush elephants, including a concave back, wrinkled skin, stocky limbs, a deep, short face, prominent brow and conspicuous orbital margins. The skull of P. magnum was not entirely known in the early 1800s and Hawkins may have taken this as an opportunity to be creative with the facial form of the larger model. His apparent referencing of elephants may seem unusual but, even though Palaeotherium was regarded as being related to horses even in the early 1800s, it was also considered it a member of Pachydermata. Today, the term ‘pachyderm’ is best known as being an obsolete taxon for elephants, rhinoceros and hippos, but in the early 1800s it included many hoofed mammals too. Under this classification, it might not have seemed much of a stretch to include some elephantine anatomy in a P. magnum restoration.

Palaeotherium magnum as we might reconstruct it today: essentially a robust, compact horse.

Hawkins’ surviving take on Palaeotherium - muddied as they’ve been by time - are not too far off how we regard this creature today: a browsing hoofed herbivore that must have looked something like a tapir or small horse. The now-lost short faces of the sitting and large sculpture are admittedly peculiar as all Palaeotherium have long, somewhat horse-like skulls (Rémy 1992), a fact well established by the 1850s. The introduction of elephant features into the P. magnum reconstruction is, of course, questionable. Elephants are now considered very distant relatives of hoofed mammals and there is no reason to think that they are a good soft-tissue analogy for Palaeotherium. The depiction of trunks is also probably erroneous. Short trunks have evolved repeatedly in perissodactyls and can be predicted for fossil species through a range of bony correlates (Wall 1980). Palaeotherium bears features indicating a particularly fleshy set of lips, but it lacks the full suite of features we associate with having a proboscis.

Anoplotherium

A parade of Anoplotherium commue hanging out at the water's edge in 2013. These remain, a few details aside, pretty darned good takes on Anoplotherium anatomy. Note the impression of musculature in the tails: even though they're hanging low, they look powerful and mobile.

Like Palaeotherium, Anoplotherium was an early subject of palaeoartistic reconstruction at the hands of Georges Cuvier. Two incomplete skeletons of this peculiar hoofed mammal were recovered from Eocene gypsum deposits adjacent to Paris at the turn of the 19th century and, with these, Cuvier was able to reconstruct most of its osteology in a series of papers published from 1804 to 1825 (see Rudwick 1997 and Hooker 2007 for discussion and references). Cuvier's skeletal reconstructions and basic life restorations of Anoplotherium were widely reproduced and would have been well-known among Victorian scholars. Cuvier privately developed muscle studies based on the same illustrations but did not publish them out of concern that they were too speculative for scientists of the early 19th century (Rudwick 1992, 1997). Cuvier was clearly ahead of his time in this regard, foreshadowing a practice that would become important to studies of functional morphology as well as an essential part of the palaeoartistic reconstruction processes.

Cuvier is thus very much the architect of the Crystal Palace Anoplotherium, and Hawkins followed his vision fairly faithfully. He deviated by giving the Anoplotherium camel-like facial details, including large lips, small, rounded ears and a sloping skull roof. Referencing camel anatomy was not Hawkins’ whimsy but informed by early ideas of where Anoplotherium sat in mammalian systematics. This depiction was a departure from scientific credibility however, and Cuvier’s take, with its lower snout and modest lip tissues, was more in keeping with the underlying skull and inferred soft-tissue anatomy of Anoplotherium. This seems to be another example of Hawkins transferring anatomy from living species rather than, as he often did, reconstructing it objectively from fossil bones. Another error is the reconstruction of four toes on each foot. Anoplotherium feet actually had three toes each: two hoofed main digits, and single, somewhat opposable ‘thumbs’ on the inside of each limb (Hooker 2007). Cuvier was aware of there being three digits on the forelimbs at least, and it’s possible that Hawkins added more toes because he thought the fossils were incomplete or otherwise somehow anomalous. After all, Anoplotherium is meant to be an even-toed hoofed mammal, and even today it's an oddball for its unusual toe counts. But other than these relatively minor errors, the Anoplotherium sculptures are compelling reconstructions that are still used to illustrate the form of this taxon today (e.g. Prothero 2017). I particularly like the strong, flexible-looking tails and the form of their muscular torsos.

Anoplotherium commune, the middle portion of a Venn diagram containing Bambi, Lassie and Rory Calhoun, in its characteristic feeding posture. Our anatomical interpretation of this animal is very similar to how Cuvier and Hawkins reconstructed it, but we have different ideas about its lifestyle.

Hawkins created three Anoplotherium sculptures: one standing, one resting, and one in a curious half-crouched pose with an outstretched neck and head*. I’m not entirely sure what behaviour the latter is meant to depict. In the early 1800s Anoplotherium was regarded as a swimming animal that used its powerful tail to propel itself through water, perhaps like an otter or coypu (e.g. Owen 1846). Maybe the third animal is meant to be shaking itself, dog-style, to dry off as it emerges from the water surrounding the Tertiary Island? The soft-tissues of the neck are inconsistent with the other models, and this is not the result of damage or poor conservation. Might it represent deformation of the skin as the neck is shaken about? Today, Anoplotherium is interpreted as a fully terrestrial animal adapted for high browsing (Hooker 2007). Peculiarities of its pelvis are shared with mammals that regularly stand upright on two legs, and it’s probable that Anoplotherium adopted this pose to browse above the feeding envelope of contemporary mammals (Hooker 2007). The strong tail, in this hypothesis, becomes a stabilising organ rather than a swimming aid.

*The 1854 Routledge's Guide to the Crystal Palace and Park at Sydenham suggests there are meant to be four Anoplotherium, but I'm not aware of any other documents indicating this. Is there another missing model, or was this a typo?

"Anoplotherium"gracilis - or, more appropriately, Xiphodon gracilis. Some authors suggest that some of the Crystal Palace Anoplotherium sculptures represent this species, but I strongly doubt this. gracilis has a completely different shape to commune and this was understood early in the 1800s. This image is by Georges Cuvier, and it pre-dates the Crystal Palace project by several decades. From Rudwick (1997).

According to McCarthy and Gilbert (1994) and Doyle and Robinson (1993), two species of Anoplotherium are represented at Crystal Palace: the two standing individuals are A. commune, and the reclining sculpture is “A”. gracilis. It’s not clear to me that this is accurate, however. Firstly, by the time Crystal Palace Park opened A. gracilis was well-differentiated taxonomically from A. commune. Cuvier placed gracilis in a subgenus, Xiphodon, in 1822, and this was erected to a full genus by M. Paul Gervais in 1845. Owen agreed with this change and stopped referring to “Anoplotherium gracilis” at some point between the mid-1840s and mid-1850s (see Owen 1846, 1856, 1857). By the time the Crystal Palace sculptures were being commissioned the disassociation between Anoplotherium and X. gracilis was thus well established, and we have to assume that Hawkins and Owen were aware of it. A complication to this is that Hawkins still referred to A. gracilis in the early 1860s (judging by the labelling on one of his 1862 posters), but this brings us to our second point: that Hawkins evidently knew how different gracilis and commune were anatomically. His 1862 posters show commune as reconstructed at Crystal Palace while his gracilis are the long-legged, long-necked, and short-tailed creatures of Cuvier and other artists in the early- and mid-1800s (see Rudwick 1997 for Cuvier’s own detailed accounts on the anatomy of this species). This isn’t surprising: in the early 19th century commune and gracilis were regular fixtures in palaeontological texts, and skilled, intelligent artists like Hawkins would not readily confuse them. This is not to say that claims of gracilis being featured at Crystal Palace are baseless, but they neither marry up with the Anoplotherium statues we have today nor the history of Anoplotherium research. As with the uncertainty about the taxonomic representation of the Palaeotherium sculptures, the poor records and deficit of historic interest in the Geological Court mammals do little to help resolve this confusion.

Megatherium

Towering above surrounding vegetation is Hawkins'Megatherium americanum, shown here as it was in 2013. There's always some vegetation obscuring this sculpture and, last time I visited the park, it was near impossible to see Megatherium at all. This obscures, among other things, the expertly sculpted feet, legs and tail. Controversy still reigned about the foot posture of ground sloths in the 1850s, but Hawkins was spot on in his depiction.

The research history of Megatherium americanum began nearly six decades before Hawkins commenced work on his model. Despite this long research lead, Hawkins’ rearing, tree-grasping Megatherium was ultra-progressive for the time. It was one of the first depictions of Megatherium in a pose that chimes with our modern understanding of giant sloth habits and actually pre-dated publication of ideas that it was capable of such feats. Megatherium was, for much of the early 1800s, regarded as Georges Cuvier imagined it in the latest 1700s: a flat-footed, trunked quadruped with particularly dextrous forelimbs (Rudwick 2005, Argot 2008). Even into the 1850s scholars were still confused over aspects of how this animal lived, with authors like François Jules Pictet-De la Rive writing long discussions about its capacity for burrowing, climbing, and harvesting vegetation. Owen's studies on another species, Mylodon darwinii, elucidated many aspects of ground sloth lifestyle and anatomy that would inform Hawkins model. Owen showed that Mylodon walked on the sides of its feet and the shorter, clawless fingers of its hands. He viewed giant sloths as browsers and tree fellers based on numerous lines of anatomical evidence (Owen 1842) and, under his direction, a Mylodon skeleton was restored as a tree-rearing biped at the Hunterian Museum in the late 1830s/early 1840s. In contrast, contemporary European mounts of Megatherium and illustrations of its skeleton retained fully quadrupedal, flat-footed stances.

The Crystal Palace Megatherium being manufactured in an image published by Die Gartenlaube in 1853. Note the size of the hands, which are much larger than the surviving hand on the model today. From Wikipedia.

Owen eventually wrote at length about tree-rearing giant sloths when discussing the anatomy and habits of Megatherium, but only well after the Crystal Palace models were completed. An article in the German magazine Die Gartenlaube shows that Hawkins’ Megatherium model was completed in 1853, a year that could - if Hawkins had been strictly following available Megatherium reconstructions - have seen the Crystal Palace ground sloth restored as a Cuvierian quadruped. The fact that Hawkins avoided this implies that he either combined Owen’s ideas on Mylodon with the anatomy of Megatherium, or else that Owen tipped him off about the direction of his future research. Either way, the portrayal of an elephant-sized mammal rearing into a tree has to be regarded as extremely progressive for the 1850s. Other early 19th century scholars assumed such animals were confined to quadrupedal poses (Argot 2008) and, while it was not a stretch to imagine the bear-sized Mylodon routinely rearing onto its back legs, it was a bold prediction to portray an enormous Megatherium doing the same. As demonstrated in many Crystal Palace models, Victorian scholars often imagined fossil animals as variants on recognisable modern forms - paleotheres as tapirs, dicynodonts as turtles, pterosaurs as birds - but Hawkins’ Megatherium was boldly different from anything alive today, and foreshadowed the way we would start visualising prehistoric species as our science and data improved.

The Crystal Palace Megatherium is of further note for being one of the oldest life restorations of a ground sloth. Though several skeletal reconstructions were published prior to the 1850s, few, if any, restorations with a complete suite of soft-tissues were attempted. (It’s curious that none have been found among Cuvier’s archives, given his links to Megatherium and his habit of restoring the anatomy of fossil mammals). Despite its vintage, Hawkins’ Megatherium has held up well as a portrayal of ground sloth form. A commendable portrayal of proportion and musculature is buried under layers of long, shaggy hair, with the muscular, relatively slender shoulders contrasting appropriately against the wide and robust pelvic region. The feet are appropriately inturned and the arms are depicted as if grasping a tree to access vegetation or push it over, entirely in accordance with Owen’s interpretations of sloth behaviour. Hawkins’ depiction of shaggy hair anticipated the discovery of giant sloth hair by almost half a century (Woodward and Moreno 1899) and, although it remains unclear whether Megatherium itself was covered in such fur, this take is certainly consistent with the fossil skin of several giant sloth species.

Megatherium americanum as we know it today - really not so different from how Hawkins envisaged it 165 years ago.

Two major difference between Hawkins’ Megatherium and our modern reconstructions are obvious. The first is the presence of a short proboscis, a Cuvierian interpretation also endorsed by Owen (1842). Hawkins’ restoration would have pleased Victorian scientists, but trunked sloths have not withstood modern scrutiny. Today, it is instead thought that ground sloths had extensive nasal cartilage and prominent lip tissues (Bargo et al. 2006), but they lack features indicative of trunks or proboscides.

It's hard to see the Megatherium sculpture in full, especially from anterior view, so I've borrowed this photo from the Friends of Crystal Palace Dinosaurs website. Note the excellent rendering of the crouching, pedolateral hindlimbs, and also the strangely small left hand (the right is missing). You can see the colour mismatch between the left forearm and elbow - this marks a site of repair where the tree outgrew the grip of the sculpture. But what's with that tiny hand? Its detailing and grafting onto the forelimb is weird and doesn't match illustrations of the Megatherium sculpture from the 1850s (above). It's surely a crudely-sculpted replacement, not a replica of the original.

The hands (or rather, the hand - the right seems to be missing at present) are the second anomaly, and are far less explicable. As represented today, the surviving hand is curiously undersized, lacks claws and is so poorly shaped that I initially assumed it was a post-Hawkins replacement, akin to the replaced Palaeotherium head. The left hand was replaced after the growing girth of the tree broke the sculpture’s left forearm, and I presumed a diminutive hand was added due to lack of space. But no, at least according to McCarthy and Gilbert (1994), the Megatherium hand currently on the model is a replica of the real deal. This seems peculiar, and I'm not sure I buy it. Hawkins’ illustrations of Megatherium from the 1850s and 60s (including artwork associated with Crystal Palace) show appropriately large, clawed hands, and an illustration of the model being constructed in 1853 (above) shows it grasping a tree with sizeable, robust extremities. The rest of the model is so exact to Megatherium form that the embarrassingly inaccurate hands are entirely out of place - they look like they were made by someone who had no idea about Megatherium anatomy, which is patently not the case for the rest of the model. I strongly suspect that the hands of the model are crude replacements of lost originals, and that there’s a missing chapter in the history of this model.

Megaloceros, the Irish elk

The Crystal Palace Megaloceros bucks and doe on display in 2018. The attention to detail on these models is superb and, today, their situation close to pathways around the Geological Court allows visitors to get extremely close.

Probably the most spectacular mammal sculptures at Crystal Palace Park are the four Megaloceros giganteus situated in at the northeastern extent of the Geological Court. A reposed doe and fawn feature alongside two large bucks, each standing in a classic ‘regal’ pose with antlers aloft. So imposing are these sculptures that they would not look out of place situated among grand governmental buildings, or atop an enormous plinth in a city square. It seems strange that no iterations of the 19th century Crystal Palace Park Guides suggested starting tours of the Geological Court with this display. The Megaloceros, after all, slowly leads us into the strangeness of extinct animals ("they're deer, Jim, but not as we know them") as well as demonstrates Hawkins’ ability to create believable animals (a fact far easier to deduce with a deer than a dicynodont). Beginning a tour from the other end of the court, with the far less impactful and more distant Dicynodon, robs us of this effect. I also feel that the grandeur and strangeness of Victorian dinosaurs, marine reptiles and giant sloths overshadows Megaloceros somewhat. Sure, it's big and the antlers are impressive, but its "wow" factor is diminished after meeting the stranger, larger reptiles situated a few hundred metres away. I can understand why Hawkins was pushing for additional, less-familiar species - mammoths, dodos, moas - to place around this end of the Court before his funding was pulled.

Hawkins had no concern for missing anatomy or predicting proportions with Megaloceros. Decades before the Crystal Palace project was even conceived, Megaloceros osteology was extensively described and illustrated. From Cuvier (1827).

Megaloceros was a historic fossil species even to Hawkins and Owen. Remains of this animal were found in the late 1600s and, by the early 1800s, enough material was known to reconstruct the entire skeleton. Cuvier (1827) published several such illustrations, including two skeletal reconstructions that were widely reproduced in later texts on fossil mammals. This, and the glut of Megaloceros material held by British museums, would have given Hawkins an excellent insight into its anatomy. Visitors to Crystal Palace would not have known the Irish Elk as Megaloceros giganteus, however, but under Owen’s 1844 name for the species, Cervus (Megaceros) hibernicus. The nomenclatural history of M. giganteus is confused by several names being coined for this species in the 18th and 19th centuries. Owen’s subgenus (eventually promoted to a ‘true’ genus) Megaceros was the first to enter widespread use and almost became the accepted generic name for giganteus. However, Megaloceros was resurrected in 1945 (albeit somewhat corrupted from its original spelling, Megalocerus) and both names were applied to the Irish Elk until the 1980s. Adrian Lister (1987) finally brought an end to decades of confusion by establishing Megaloceros giganteus as the most appropriate name on grounds of both nomenclatural priority and usage.

Hawkins'Megaloceros doe and fawn, as seen in 2013. I really enjoy the detailing on their feet - if there was any doubt that Hawkins could make realistic-looking familiar creatures as well as weird fossil ones, these models dispel it.

Megaloceros was surely the least demanding of Hawkins' reconstruction assignments because of its close relationship to living deer. As did Cuvier, Owen realised that early interpretations of Megaloceros as a giant moose-like cervid were incorrect, and he placed it among Cervus, a genus that includes several other large, Old World deer species (e.g. Owen 1844). Hawkins appears to have referenced several Cervus anatomies in his reconstructions, especially the thick neck manes, deep fur over the withers, and a line of long, shaggy fur along their bellies. These are especially obvious on the bucks, but also present on the reclined doe. Manes are not common to many deer females, and I suspect Hawkins was referencing the winter appearance of certain elk subspecies (‘elk’ as in the wapiti Cervus canadensis, not the Eurasian elk/moose). The short, blunt tails seem to agree with this interpretation too. It would later be traditional to reconstruct Megaloceros like the red deer Cervus elaphus, but I wonder if Hawkins thought the shaggy appearance of winter elk was more apt for an Ice Age animal, or else if he thought the longer fur would look more obvious on his sculptures.

Hawkins' reconstructions of Megaloceros are, of course, some of the most scientifically credible of all his Crystal Palace artworks. But I have to admit that, on grounds that their restoration was nowhere near as complex as the other sculptures, I don’t think they’re the best examples of his palaeoartistic abilities. They certainly leave little doubt that Hawkins could produce convincing portrayals of semi-recognisable animals, but Megaloceros probably wasn’t much of a stretch for him. His artistic expertise included illustrating living mammals and he eventually wrote a series of books on this very topic (including one featuring deer, in 1876). For me, it’s his deductions about lesser-known and wholly unfamiliar fossil species that place him among the old masters of palaeoart, even though these insights are associated with sculptures that are scientifically more dated.

Today, we imagine Megaloceros almost as Hawkins did, excepting some different ideas about their colouration and soft-tissue anatomy. These have been provided by cave art and revelations about their relationships with modern deer.

While Hawkins’ Megaloceros are impressive reconstructions, they differ from our considerations of this animal today. It seems that Megaloceros was more closely related to fallow deer Dama than Cervus, and this implies some differences in facial anatomy and colouration, as well as some particulars of fur and soft-tissue distribution (e.g. a bulging laryngeal region and brush-like genital sheath). Some of these anatomies are confirmed in Megaloceros cave art (Geist 1999; Guthrie 2005), which also records other details unknown from fossils. These include a shoulder hump (presumably long hairs, fat or both) and a series of dark stripes: one at the base of the neck, one running from the shoulder towards the knee, and another surrounding a pale rump. Cave art also suggests, though not conclusively, that the head and neck were pale or white, while the body was darker, perhaps light brown. (There's a terrific summary of Megaloceros life appearance over at Tetrapod Zoology - check that out for additional details and discussion). This information was entirely unknowable to Hawkins, however, as the discovery of ancient European cave art post-dated the Crystal Palace project by over a decade, and its acceptance as the work of authentic Palaeolithic humans, and not modern vandals, was even longer coming. Moreover, even once ancient cave art was accepted as a genuine part of European history in the early 20th century, it would take decades to discover enough Megaloceros cave paintings to deduce meaningful details of its anatomy and colouration.

So, about those Crystal Palace Dinosaurs...

References

Very awesome take on the teratornithid Teratornis merriami by Charles Knight. Like virtually all illustrations of teratorns, the implication of this image is that Teratornis is a scavenger, arriving to steal parts of this American camel (Camelops hesternus) from noble Smilodon. But how accurate is this widely portrayed view? Image © AMNH, borrowed from Gizmodo.

Teratorns (formally known as Teratornithidae) are a group of large to gigantic raptorial birds that roamed the Americas for much of the Neogene, only becoming extinct about 11,000 years ago. On account of their large size, carnivorous habits and association with charismatic mega mammals, they are some of the most famous of all fossil avians. The most widely known teratornithid is surely Argentavis magnificens, a Miocene Argentinian species often regarded as the largest flying bird of all time, but our most complete picture of their anatomy stems from Teratornis merriami,, a 3.5 m wingspan taxon from the Pleistocene La Brea Tar Pits. Exactly where teratornithids fit into avian evolution is not entirely resolved but they likely have close affinities with New World vultures, Cathartidae (Mayr 2009). Traditionally, this would have made teratorns relatives of storks and herons, but recent shifts in avian phylogenetics have seen cathartids reclassified as Accipitriformes, a large raptor group only excluding falcons and owls. This being the case, Teratornithidae should be regarded as Accipitriformes as well.

Images of giant prehistoric animals covered in thick, fluffy coats are par for the course in modern palaeoart, including lots of my own (image above shows Therizinosaurus, from 2015). But... hey: just how warm are these multi-tonne animals under all that fuzz?

Rendering giant prehistoric animals with extensive hairy coats or thick feathery coverings is a convention now so well established within palaeoart that few of us give it a second thought. While this practise is well-grounded in fact for some cold-adapted Pleistocene megamammals, such as woolly mammoths and woolly rhinoceros, our treatment of other giant species - giant sloths and giant coelurosaurs - has a greater basis in tradition and expectation than fossil data. We have, after all, mostly lacked detailed insights into the skin of these giant extinct animals, and have thus relied on scraps of soft-tissues and phylogenetic bracketing to inform our art.

My artistic history firmly places me on the megafuzz bandwagon. Earlier this year I painted a shaggy Megatheriumand since 2013 I've painted woolly Pachyrhinosaurus, several extensively feathered tyrannosaurs and a Therizinosaurus with more feather coverage than most modern birds (above). But I was recently given pause to question these reconstructions when Dennis Hansen, one of my excellent patrons, asked about the possibility that giant sloths, such as Megatherium, were largely or wholly devoid of hair because of issues with thermal energetics. At that size, wouldn't giant sloths be far too warm? This idea has been promoted by some sloth researchers (Fariña 2002, Fariña et al. 2013) but it's rare to see it expressed in palaeoart. Megasloths are, near-universally, restored with the same shaggy fuzz first given to them by Benjamin Waterhouse Hawkins in 1854 and it now seems shocking and wrong to see one without that characteristic pelt. Should you want to draw one, you have to fight your hand - Evil Dead II style - to force those strange, hairless contours onto the canvas.

Cover art for Luis Rey's 2019 book Extreme Dinosaurs Part 2: The Projects, featuring the latest incarnation of Luis'Deinonychus. Notice the presence of lips. Image borrowed from the Luis V. Rey Updates Blog.

Cover of the first Extreme Dinosaurs, borrowed from Amazon.com, featuring the earliest version of Luis'Deinonychus. Such extensive feathering was pretty radical for Deinonychus in 2000, and there's an even more 'extreme' version inside.

What they're calling "the best trilogy since the original Star Wars films": Abby Howards' Earth Before Us series. Available now from Amulet Books (1st, 2nd and 3rd books) as well as good online book retailers.

Each of the Earth Before Us books is an affordable (RRP £10.99/$15.99), well-produced hardback with a solid, durable feel, of about 130 pages long*. They feature the time-travelling adventures of two characters, school pupil Ronnie and her palaeontologist friend and mentor, Miss Lernin. Initially inspired to visit the Mesozoic to help pass a class exam on dinosaurs, Miss Lernin and Ronnie then travel to the Palaeozoic after visiting an aquarium (Ronnie is surprised at the antiquity of many invertebrate lineages) and the Cenozoic when Ronnie wants to see how ancient humans dealt with cold. These human plots are really narrative bookends and, instead, the pacing and story developments stem from the evolution of life throughout the Phanerozoic. Journeying rapidly through time and space, our characters visit different organisms and locations so that the books never become boring or repetitive, swapping intimate moments with small critters to double-page spreads packed with gigantic animals. There are no clunky narrative devices to move Miss Lernin and Ronnie around, either. Save for starting their journeys in time by climbing into various bins (of course), they otherwise instantaneously travel to wherever they need or want to be, and without fear of the consequences. It's a smart narrative device that reminds me of the 'Ship of the Imagination' used in the TV series Cosmos, focusing attention on what our protagonists have to say, and the worlds they encounter, rather than tying them to a tedious travelling mechanism. They periodically return to the Learning Centre, a tranquil location equipped with a whiteboard that's periodically visited to explain a major concept of biology or palaeontology, but otherwise Miss Lernin and Ronnie move through time and space with pace and fluidity.

*I learned when finishing this article that paperbacks are now also available, RRP. £6.99/$9.00 

This speed is not to say that Earth Before Us skimps on detail, however - far from it. These books are dense, with heaps of information and depictions of extinct organisms, landscapes and climatic conditions. In the wrong hands, this could be overwhelming, or a barrel full of outdated data and misinformation. Neither fear is realised. Abby is terrific at distilling complex geological, evolutionary and anatomical information to words which are understandable to young people and lay audiences, all without dumbing down or patronising her readers. The interpretations she presents are accurate to modern science, and she takes time to explain why some ideas are superior to others or where gaps lie in our knowledge. The scientific concept is a major success of the books, and teachers, parents, exhibition designers and other authors looking for effective ways to teach natural history should pay close attention to her craft. Topics such as cladistics, extinction events, speciation, natural selection and so on have rarely seemed so graspable, and I can only see these books as a window into a wider world of learning for readers young and old.

Double page spread of Late Cretaceous South America from Dinosaur Empire! - note the swimming birds and fluffy baby Carnotaurus. I really like the sense of scale in these images: the human characters obviously help a lot in this regard, but the use of light and space does a lot of heavy lifting too. © Abby Howard.

As demonstrated by the accompanying images (kindly provided by Abby - many lack their speech bubbles so we can see the art more completely), the artwork in Earth Before Us is superb. Abby's illustrations are wonderfully clear, detailed, and characterful. On more than one occasion I found myself chuckling over the wordless reactions or expressions of the protagonists (see, for example, Miss Lernin's reaction to Ronnie riding a Tyrannosaurus, below). The fossil species are also well-executed, being thoroughly modern (lips and fibres abound on dinosaurs, animals are given generous amounts of soft-tissues etc.) and anatomically accurate enough to be recognisable to their fossil skeletons. The presence of human characters on every page gives a great sense of scale to the animals and, by using both in the animal's expressions and their interactions with Miss Lernin and Ronnie, Abby imbues heaps of character into her extinct subjects. It's clear that Abby sees extinct species as being animals, not monsters, adding another welcome contrast to so much child-focused palaeo content.

There's lots to like about the general tone of the Life Before Us series as well. They celebrate education and learning, and present knowledge and science as tools to solve problems. The arcs of each book involve Ronnie gaining greater knowledge and understanding of not just the past, but natural history and learning in general. Subjects that were once of no interest to her become fascinating, and in one book she's shown imparting her knowledge to others. The books are also not afraid of tackling difficult topics, such as climate change and our current biodiversity crisis. These are addressed in a frank, but also hopeful fashion, which is appropriate for younger audiences. I hope, as the books suggest, that these sections inspire children to ask more of adults as goes taking responsibility for these disasters.

Special attention must also be drawn to the main characters. Palaeontological outreach has a strong bias towards casting white men in prominent roles, and especially white men in wide-brimmed hats and field gear. As explained by Elsa Panciroli in an excellent 2017 article, this stereotyping of palaeontologists goes to the core of our profession. Like many sciences, palaeontology struggles with gender and ethnic diversity, and our lack of varied faces in outreach probably doesn't help this. It's very welcome, therefore, that the Earth Before Us books exclusively features two female protagonists, one of whom is black, and without a cowboy hat or rock hammer in sight. Miss Lernin even wears a dress throughout the second book, showing that you can have extensive knowledge about the history of life without wearing Gore-tex. Also noteworthy is that the books do not question the qualifications or intentions of its main characters either: there's no "but you're a lady?!?" revelation that Miss Lernin is the series' palaeontologist or whatever. The characters are simply allowed to be who they are without second-guessing. It seems strange to feel that this is such a big deal in 2019, but, times being what they are, I am very pleased to see Earth Before Us giving a much-needed injection of cultural, gender and ethnic diversity into mainstream palaeo media.

So, in sum, these are great books. The science and artwork are superb, they're both smart and funny, and they manage to make important points directly (climate change, extinctions) and subtly (gender and ethnic diversity). I can't recommend them highly enough, and even if your kids are a little too young to read them on their own, I think they'd be fantastic to read with them. But that's enough about what I think: let's see what Abby has to say about her work. All artwork shown here stems from Abby herself, and is reproduced with her permission.

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MW. The Earth Before Us books are packed with personality and charm, and were clearly written by someone with a major passion for natural history. How much of your own interests do they reflect? Do you share Miss Lernin's enthusiasm for just about everything that walks, crawls or flies, or did you initially have interests in a few fossil groups, and branched out for this project?

AH: Thank you! I did start each book with favourites in mind, but as I spent more time thinking about and researching the creatures in the series, I came to love almost all of them. The script is basically word for word the way I fawn over wildlife. I'm insufferable at museums and zoos.

It seems that if someone spends enough time researching a plant or animal, it's easy to become enamoured with it, which is fortunate for folks like me who may have started a book series about ancient beasts while not being particularly passionate about things like ancient echinoderms. As it turns out, they were really weird and interesting and fun to draw! I was also not so keen on temnospondyls for some reason, despite now feeling like they have great horror potential. We don't take their modern relatives very seriously, since they're pretty cute and small, but I feel as if amphibians are some of the coldest, least discerning modern predators that'll swallow almost anything that moves near their mouths. It's cute when it's my axolotl trying to swallow my relatively gigantic human fingers, but if it were a 20-foot-long river monster trying to swallow my entire human body... anyway, as a horror fan, once I gave temnospondyls the time of day, they easily became a new favourite.

But there are some beasts that never wound up winning me over, namely trilobites. Don't get me wrong, I'd still cry tears of joy if I saw one in real life, but they're not exactly in my top ten. Or top fifty.

It turns out that lots of extinct animals are surprisingly happy to be petted: here's the proof. Ronnie's responses to certain animals are not always as gushing as Miss Lernin's, but several species - and not always those you'd expect - score very high cute points. I expect Mesozoic crocodyliforms to be every kid's favourite fossil animals after reading these books. Excerpt from Ocean Renegades, © Abby Howard.

You have a background in comics and writing, as well as a huge passion for horror films - where does prehistory fit into this? How often have extinct animals featured in your projects, illustrated or otherwise?

I think these things feed into each other more than one would expect, especially when it comes to worldbuilding and creature design. Knowing how the world came to be is, in my opinion, the best way to know how to build a new one, and that goes for building creatures and monsters, as well. Even if you're creating something humanoid! I'm constantly using my database of weird critters that exist or have existed to make my designs more interesting. Grounding your design in reality, while it may seem counter-intuitive when trying to create something otherworldly, has proven to be really effective for me.

Well, that and looking up gross corpses. Those are my two types of monsters: critters and corpses.
As for examples of how prehistory has bled into my other work, I'm currently working on a book of short horror comics set to be published next year, and one of the stories features a nessie-esque lake monster that's a mashup of an alligator, a marine iguana, and of course, a plesiosaur. The recent research on the body shape of plesiosaurs has, I think, finally made them look more like believable living creatures, and I leaned heavily on their new meaty shape for the silhouette of the monster in the story.

A busy scene from Ocean Renegades. Despite Abby's horror leanings, this is about as 'monsterised' as the Earth Before Us restorations get, which is terrific. We get the sense that these animals are dangerous carnivores, but not that they are ravenous killing machines. © Abby Howard.

Child-orientated palaeo education often seems less concerned with learning and knowledge than simply using dinosaurs as kid-friendly entertainment. The Earth Before Us series, in contrast, is smart and educational while also being entertaining and approachable. Indeed, the content and clarity of your books makes them great for anyone to read, not just kids. Can you tell us what inspired you to write them, and how you see them in the context of other child-focused palaeo outreach?

Honestly, this may be a little petty, but I was unsatisfied with a lot of the dinosaur books I was seeing. Even beyond the books that are outright inaccurate, I hadn't seen any that went far enough in their explanations to satisfy what I thought could be done with the genre. I wanted something that showed these creatures in their natural habitat, surrounded by diverse animal life and at least one human for scale. That last part was important to me-- I felt it would contextualize the size of ancient beasts in a way that simply throwing out lengths and weights can never do. You can tell me the height of a T. rex til the cows come home, but unless I see a human standing next to it, it won't stick with me. Though I'd be lying if I said I didn't also love drawing myself next to all my favourite extinct creatures.

I had also seen a lot of books that tackled the "what if the information in the book is obsolete in the next few years" issue by simply not embracing any current research at all, and just giving nods to the by now widely-accepted fact that certain dinosaurs had feathers (while still drawing them as skeletal monsters with huge teeth and claws and maybe a couple feathers sticking out of their heads). That was so frustrating, especially since it could be turned into a useful teaching moment about scientific theories and perhaps lead to fewer adults becoming horrifically incensed when palaeontologists dare add anything to dinosaur models. So I wanted to make a book that was as up-to-date as I could, and didn't worry about whether it'd all be obsolete in a few years. And it sort of is-- my T. rex is far too fluffy! The naked skin samples were found the year after the first book was published. But I don't beat myself up about it, because it's better to take risks than to perpetuate ever-more-outdated perceptions.

A double-page spread of the glorious late Eocene from Mammal Takeover. The unobtrusive labelling adds a layer of additional information to every page, and gives the opportunity to learn about species not being directly discussed by the main characters. © Abby Howard.

I'm curious how you approached the Palaeozoic-focused Ocean Renegades and Cenozoic-focused Mammal Takeover, given that they lack audience-pleasing (and thus bookselling) non-avian dinosaurs. How did the general lack of A-list fossil species in the Palaeozoic and Cenozoic affect the creation of these books? Were you ever tempted to tell your story in one volume to get around this issue, or did you always envisage a comic trilogy?

I was surprised at how easy they were to sell to the publisher, and I'm so glad they decided to take a chance with the series. I'd originally planned to do one book (just about the Mesozoic), but they offered me three so I felt it would be a good idea to go ahead and cover everything that's ever lived, if I could. And since the first book was pitched as a deep dive into the Mesozoic, specifically focusing on creatures that don't usually get the spotlight, writing follow-up books about even more obscure creatures was an easy sell! I feel incredibly fortunate to have had very understanding editors who didn't push back when I wanted two-page spreads about early annelids and echinoderms, bless their hearts.

I also think in some ways the fact that I highlighted so many different animals was itself marketable. Kids love illustrations with a lot going on and lists of facts, and my books definitely have those things. I wrote these books for the encyclopedia-reading kid I used to be, and as it turns out, there are a lot of kids who are looking for books like these.

Your depictions of fossil animals are very modern: there is fluff and fuzz on your dinosaurs, most animals are lipped, and all they sport generous amounts of soft-tissue. At the same time, the reconstructions are necessarily stylised to some extent, to fit the comic world you've created. Can you take us through how you created your fossil animals? Where did you find the compromise between your own style and following fossil data?

The compromise was mostly made for me based on the limitations of my own style! The way the creatures are drawn was often was as good as I could get them with my current skillset and the looming deadlines. I would start with the best material I could find for the particular critter-- for this, I thank both you and Scott Hartman (of skeletal drawing) for the paleoart resources you provide. I also thank all the people who take pictures of fossils in museums that are too far away for me to visit and put them online, though I wish more of them would include a photo of a plaque saying what animal it actually is. And like any paleo-artist, from there I used slightly similar modern animals for soft tissue anatomy reference, which helps the drawing look more like something that could be alive. From there, the stylization was up to how well I could translate the reference material into shapes that didn't look awful, haha.

I think the hardest part was fitting so many animals on each page. That wound up setting limitations as well, since I had to make sure the animals weren't blocking each other too much but were also interacting in an engaging way.

The plump plesiosaurians of Dinosaur Empire! These animals are not stylised to look this way: there is good fossil evidence that Mesozoic marine reptiles were covered in thick, fatty tissues, just like living secondarily aquatic tetrapods. It's good to see these discoveries being reflected in modern books. © Abby Howard.

The lack of fighting and violence in these books is a breath of fresh air. Even Tyrannosaurus, which by unspoken Laws of Palaeo Media should be shouting and stomping its way around the Late Cretaceous, is depicted more like a lazy cat. While the images and text don't downplay the fact that many extinct animals were probably dangerous, and we see several predatory acts, you demonstrate prehistory with nuance: fossil animals can also be cute, majestic, nurturing and amusing, as well as aggressive. Was this a deliberate response to all the aggressive behaviours featured in palaeo-themed books aimed at children?

Absolutely! I feel like the emphasis on violence in paleoart is super boring, especially in the way it makes people feel like ancient beasts are movie monsters rather than actual animals, and that if they aren't scary they're dumb and lame. I'm a big proponent for paleo media that depicts ancient beasts as normal animals with a normal level of aggression, and can't help but roll my eyes when a narrative focuses on The Hunt or culminates in a big fight between toothy, scaly monsters.

Though I do like when nontraditional predatory behaviour is depicted-- when I was young I saw a documentary that featured spinosaurus hunting for fish and LOVED it because it wasn't just some big monster fight. It felt so much more like an animal just trying to live. This goes for scavenging, as well. I always found the "debate" about whether large predators like T. rex were active hunters or scavengers to be so pointless. As if any self-respecting predator would pass up a perfectly good rotting carcass. That's a free meal!

But my personal favourite media is always the stuff that emphasizes the quiet moments-- a creature wandering through a rainy forest with the bellows of a far-off beast in the background, napping in the shade on a hot day, chasing bugs, taking care of its babies. I go nuts for that stuff. My kingdom for a documentary with no narration that follows a dinosaur through its daily life.

The Dinosaur Empire! take on Tyrannosaurus. This mighty beast is roused from its slumber having sensed human prey, rises to its feet, opens its mouth and... yawns. Note the crushed ferns where it's been lying down: this Tyrannosaurus evidently enjoys a good snooze. © Abby Howard.

I want to talk to you about the protagonists of Earth Before Us, Ronnie and Miss Lernin. Palaeo media still largely depicts palaeontologists as rugged, Indiana Jones-esque men, and young dinosaur fans tend to be boys. You've turned this on its head by featuring a young black girl and a female palaeontologist who - holy cow - doesn't even wear field gear! How do you see Ronnie and Miss Lernin in context of wider conversations about stereotyping scientists, and the growing call for more diverse voices in science and education?

I'm very glad I was able to contribute my little piece to help change the public perception of who is interested in and pursues this sort of work. I want kids to take for granted that yes, of course women and people of colour can be palaeontologists. I want it to be a given, and I hope seeing characters like mine can help.

I was fortunate enough to be part of a natural history program that was led by both men and women, and the undergrads I took classes with were majority women. However, it's still the case that many femme folks don't feel comfortable pursuing higher degrees in their field after graduating. I'm sure a large part of this is the competition in these fields-- most people in general won't pursue a higher degree. But there's definitely a discomfort when you're applying for positions and the people you'd be working with clearly think less of you and think you aren't as capable. A friend of mine applied for field research positions after she graduated, and one of the interviewers wound up telling her that she wouldn't be able to "spend a lot of time in the mornings doing her hair and makeup". As if her merely being a woman meant she did those things, took a lot of time each day even while camping in the desert to do those things, and that it would be a great detriment to her career to want to do those things. The fact that this was something the interviewer felt needed to be brought up just because she was a woman speaks volumes about how he perceives women, and how he clearly doesn't think they could be prepared for field work, despite the fact that my friend had field experience. I know I wouldn't want to work with that person. And if every person you encounter is like that, of course you might decide not to pursue that career.

I will say, however, that I left the program not because I felt uncomfortable being a girl in STEM, but because I was a terrible student, haha. I make a much better cartoonist.

Mammal Takeover devotes several pages to discussing human-led environmental crises, a circumstance paralleling a book I've just finished on the history of life. To me, humanity's major and lasting environmental impacts feel like an essential part of the story of life on Earth, and omitting them feels somehow complicit and accepting of our deepening environmental crisis. Did you have similar thoughts working on Earth Before Us? And how do you sell issues like conservation, the politics of climate change etc. to young audiences?


Those were very difficult and depressing pages to work on, but definitely necessary. Not only because it's a subject that needs to be discussed at every opportunity, but because it's a huge part of the world we're living in today. I couldn't just leave it at "and then all the modern animals evolved and we all lived happily ever after" when the presence of humans is causing the sixth mass extinction.

One of the gutsiest parts of the series is the closing segment of Mammal Takeover, where Ronnie asks Miss Lernin about the sixth great mass extinction and the role humans are playing in it. As demonstrated by this page, the tone struck here is frank, but also hopeful and empowering. © Abby Howard.

Writing about climate change for kids was no small task, and I hope I did a better job than the media I grew up with. I've always had a disdain for the way climate change is discussed with kids-- there always seems to be an emphasis put on personal accountability, which for me mostly led to anxiety and hopelessness. I would stress about leaving the water running or driving places instead of walking, meanwhile corporations I have zero control over are out there tearing down forests and ripping holes in the ozone layer. I didn't really want to put in any of those "here's how you can help" tips to avoid doing that same thing to the next generation, but when the time came to write that section, I didn't want to just say "oh yeah, rich people are just wrecking the earth and there isn't really anything you can do except beg your parents to vote for people who say they'll do something about it, which is also not a guarantee that something will be done about it". So I did wind up putting in some little tips, because otherwise it would have been a pretty dismal chapter. Plus, I do think there's no harm in doing these seemingly small things to help out in whatever way you can. You don't have to be perfect, but as I said in the book, if those folks are gonna keep ruining the environment no matter what you do, you might as well go ahead and plant that tree or get those LED lightbulbs or go vegan. Because if so many people wind up doing these things that being a little environmentally-conscious becomes the norm, that's still a net positive!

Do you have any future plans for the Earth Before Us series? I can see this readily lending itself to museum exhibitions, TV shows and toys. Will we at least get more books with these characters? "Miss Lernin and Ronnie...IN SPAAACE"?

Alas, these are the only three books I had planned! I don't know anything about any other subjects. Especially space, which I don't think I'd ever be able to make anything but horror comics about. Space is scary! No one should be up in it!

A TV show would be an interesting idea, though, and extremely fun to write. I may have to keep that in mind...

Finally, where are the best places to keep up with your work online, and how can we support you creating more art, comics and books?

The best place is probably my twitter, where I'm most active: @abbyhoward. I also have a website where I post links to my webcomics and various books: https://abbyhowardart.myportfolio.com/. You can support me on Patreon to help me keep making comics forever: https://www.patreon.com/abbyhoward. And I also have an online store! https://topatoco.com/collections/abby-howard

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Thanks to Abby for giving her time to answer my questions, I hope you found her insights into this awesome series as enjoyable to read as I did. There's still time to grab Dinosaur Empire!, Ocean Renegades! and Mammal Takeover! as Christmas gifts: steer your browsers towards those links (or the book store of your choice) and grab them before it's too late!

Where, when, and how much?

Portsmouth and the Solent from the air. The sun always shines here, and it never rains. Photograph © University of Portsmouth.

How to book

Hello, 2017 painting of sheathed-horn Arsinoitherium zitteli. Time to see if we can figure out what those horns were for, other than looking regal in artwork.

Recently, I was in the Teylers Museum, Haarlem, for the opening of their sensational palaeoart-themed Dinomakers exhibit*, where a fine cast of the skull of the Palaeogene Afro-Arabian embrithopod Arsinoitherium zitteli is perched in the main fossil gallery. Arsinoitherium is a pretty darn fascinating mammal that we're all familiar with, yet we rarely give exclusive focus too. I assume this reflects its scientific vintage. Arsinoitherium was discovered well over a century ago and is now featured in so many books and museums that it's part of the popular palaeo furniture. Its size, fantastic cranial horns and status as the last of the embrithopods make it a remarkable and charismatic fossil species, but it just doesn't seem to be cutting it with the kids.

*If you're a regular reader and are in the Netherlands before June, you really want to check this out. It has heaps of original palaeoartworks, including many by classic artists - Hawkins, Knight, Burian, and some exceptional modern work from the Kennis brothers. I have stuff there too.

Today, Arsinoitherium is mostly discussed by palaeontologists documenting new Palaeogene faunas in Eocene-Oligocene sites of Africa and the Arabian Peninsula, but several fascinating behavioural and ecological revelations about this sometimes controversial mammal have also been published in recent years. It's increasingly apparent, for instance, that Arsinoitherium was anatomically conservative, the oldest members of the lineage being little different, morphologically speaking, to the youngest. Despite this, it was a very long-lived and widespread genus which must have been highly adaptable to demonstrate sustain such a broad geographic and stratigraphic range (Jacobs et al. 2005). It evidently lived in a range of habitats, the most surprising of which are upland regions well away from the coastlines and estuaries thought to be traditionally Arsinoitherium country (Kappelman et al. 2003). This adaptability occurs despite the unusual multifunctional dentition of Arsinoitherium being adapted to specialised browsing (Court 1992): perhaps it was more of a generalist than we realised.

More specific insights into Arsinoitherium palaeobiology have been proposed too. Studies of their ear anatomy, principally for their phylogenetic signature, have found adaptations to hear infrasound in the same manner as modern elephants (Benoit et al. 2013), and a compelling case is being built against the popular idea that Arsinoitherium was a hippo-like semi-aquatic animal. This proposal was founded on both functional and taphonomic grounds (e.g. Court 1993) but a suite of opposing data, including tooth wear, occurrences in relatively dry palaeoenvironments, the presence of graviportal limbs and details of bone chemistry, are now pointing to more terrestrial habits (e.g. Clementz et al. 2008; Sanders et al. 2010). Revisions to Arsinoitherium taxonomy are also shedding insights on behaviour. Two Arsinoitherium species are now recognised - the well known A. zitteli and the larger, relatively longer-legged A. giganteum - and prior taxonomic distinctions accounting for a third species are now interpreted as evidence of probable exaggerated sexual dimorphism in A. zitteli (Sanders et al. 2004, 2010). Behind the scenes, we're building a developed picture of what Arsinoitherium was like as a real animal, and not just a long-standing museum fixture.

One of my favourite images of Arsinoitherium is this 1907 piece by Charles Knight, published in Osborn (1907). Despite that awesome headgear, Arsinoitherium isn't often illustrated doing much else than standing around, so it's nice to see it having something to do. Hat-tip to Chris Manias for posting this image and making me aware of it.

But one aspect of Arsinoitherium palaeobiology that does not seem to have been discussed at length is horn function. Long-term readers may recall that this is not the first time I've mentioned these structures, as the life appearance of Arsinoitherium horns was the exclusive subject of a 2017 blog post. The take-home of that article is that we artists have probably been incorrect in generally restoring Arsinoitherium horns with facial skin. Rather, their horn surface texture, structure and growth mechanic is consistent with a bovid-like horny sheath. This is not a new idea, with sheathed horns being proposed by several authors (e.g. Andrews 1906; Sanders et al. 2010), but contradicted by others (e.g. Prothero and Schoch 2002; Rose 2006).

Assessing life appearance already tells us something about horn function as a covering of tough, insert tissue has some major biomechanical implications. Arsinoitherium horn cores are deceptively delicate on account of their hollow construction. Despite the skulls of these animals reaching over 80 cm long and their owners attaining masses of around two tonnes (Sanders et al. 2010), Arsinoitherium horn cores were constructed from bones just 5-10 mm thick. Without additional protection, such delicacy might prohibit antagonistic use and a more passive function would seem likely, such as visual communication or acoustic augmentation (sensu Benoit et al. 2013). But modern species show that a horny sheath over a hollow horn core creates an amazingly strong, impact-absorbing and bending resistant organ that can be used to bludgeon, wrestle and lance other animals or to forcefully modify the surrounding environment. The physics of this is pretty simple: the hollow bone core provides great bending resistance and reduces weight, while the horny sheath absorbs and dissipates shocks and impacts (Drake et al. 2016). We've seen this exact configuration evolving time and again across Tetrapoda, and its presence in Embrithopoda shouldn't be viewed as weird or improbable.

Partly restored left horn of the Teylers'Arsinoitherium zittelli skull showing the characteristic epidermal correlates (numerous oblique foramina and anastomosing blood vessels) for a bovid-like horn sheath. These horns are identical in texture to what you might see under a cow horn.

But while the horns themselves look formidable enough, their use would be limited without a substantial neck to support and wield the head. It's for this reason that I was pleased to see the Teylers' skull without any pesky postcrania obscuring details of its posterior face. The rearward aspects of animal skulls are often overlooked in favour of more spectacular anatomy but, if you're seriously interested in the functional morphology of fossil animal crania, you need to look at the occiput and other aspects of the posterior skull surface to assess the head/neck soft-tissues. These regions reveal much about neck muscle size and distribution, as well as something of head mobility via the shape of the occipital condyle. Even at a glance, you can often say something intelligent about how animals were wielding their heads by looking at the posterior skull.

I was thus greatly interested to see that the Teylers' posterior Arsinoitherium skull bore several features unfamiliar to me from other large animals. Here's what you can see of the back the skull as it stands in the Teylers gallery. I think there's some reconstruction in places but the skull of Arsinoitherium is completely known from several specimens, and any sculpting seems to be a faithful recreation of real anatomy.

Posterior view of the Teylers Museum Arinoitherium zitteli skull cast, as seen in January 2020.

And here's the same thing, more or less, as illustrated by Andrews (1906):

Image from Andrews (1906, courtesy Wikimedia), public domain.

The beautiful tiny fossil skull of Oculudentavis khaungraae in its amber tomb and reconstructed state, as figured by Xing et al. (2020). Behind this beauty, however, lies an ugly, seemingly under-known truth about where these amazing amber specimens come from.

Recently, I shared this image of our greyhound, Beau, next to a Velociraptor* skeleton on social media. Twitter quickly lit up with likes and comments...

We test-mounted a Velociraptor skeleton yesterday, allowing comparison with our greyhound, Beau. She's a large-ish dog (27kg), and we all know Vel. was no giant, but it's surprising to see the skeleton so dwarfed by a common family pet. Puts a new spin on Velociraptor for me. pic.twitter.com/c2OPBv7qJC

— Mark Witton (@MarkWitton) March 1, 2020

...many of which remarked on how, despite being dwarfed by a big, but not exceptionally large dog, Velociraptor was still a formidable animal that would turn Beau into mincemeat should the two ever meet in real life. Poor old Beau. She doesn't deserve that: she's barely a risk to a bag of kibble.

*Probably 'velociraptorine', to be honest: there's some uncertainty about the identification of the specimen this replica was cast from.

Reading through the comments on this tweet reinforced how Velociraptor-like dinosaurs have been mythologised in popular culture. Thanks largely to Jurassic Park, Raptor Red and other 1990s palaeo media, these dinosaurs are regarded as some of the fastest, most vicious and meanest creatures of all time. Commonly discussed aspects of their savagery include razor-sharp claws capable of ripping into and disembowelling prey; strong legs for delivering rapid slashing attacks; ferocious bites and flesh-rending teeth; cheetah-like speed and agility; and high intelligence. They sound, from this description, like some of the most terrifying predators to have ever existed.

As is often the case, our pop culture takes on Velociraptor and co. have not always aligned with scientific thinking. A case can be made for Velociraptor-like dinosaurs having attained a near-fantastical public reputation reminiscent of Western pop-culture takes on ninjas. Both are genuine historical entities capable of awesome and fascinating feats, but both are also so fundamentally and unrealistically overhyped by popular culture that they bear little resemblance to the real deal.

To attempt to shed some real light on what these famous but often misrepresented dinosaurs were like, I want to compare our pop-culture takes on Velociraptor and similar dinosaurs with some of our more robust recent science on these animals. My intention is not to provide a tried and tested "what Jurassic Park got wrong about Velociraptor-type post" or to discuss basic stuff you can read about elsewhere, like the undoubted presence of extensive feathering in these dinosaurs (Turner et al. 2007; DePalma et al. 2015), but to focus on aspects of lifestyle, biomechanics and ecology. There's a lot to talk about here, so I'm dividing this article into two posts.

The 1993 Jurassic Park Velociraptor, a Hollywood creation that introduced much of the world to dromaeosaurid dinosaurs, and which probably remains the chief point of public reference for their appearance and behaviour. There is, of course, a slew of well-known anatomical issues with the JP Velociraptor that conflict with science published in the last few decades, but that's not what I want to talk about here. Image © Universal, I'm not sure who originally put it online.

Before we begin we need to quickly discuss some aspects of terminology. Firstly, exactly what group of dinosaurs are we focusing on here? Velociraptor is a member of Dromaeosauridae, a group of bird-like feathered theropods generally characterised by large, sickle-shaped claws on their second toes; long, stiffened tails; and narrow, lightweight skulls lined with sharp, serrated teeth. Fossils show that their feathering was broadly comparable to living birds such that, in life, they probably looked like long-tailed, toothy avians. But dromaeosaurs were a diverse bunch which, in addition to Velociraptor-like forms, also included the long-skulled, long-legged unenlagiines, the small-bodied and sometimes 'four winged' microraptorines, and the newly identified Halszkaraptorinae, an enigmatic group containing the semi-aquatic Halszkaraptor. The "raptors" of popular convention - mid- to large-sized dromaeosaurs with large foot claws - are perhaps best matched among palaeontological classifications by Eudromosauria, a group generally considered to include several household names: Velociraptor, Deinonychus, Utahraptor, Dromaeosaurus and others. Eudromaeosauria is not a universally recognised group as the exact composition and arrangement of Dromaeosauridae remains the subject of ongoing study. However, it's a neat match for the public perception of dinosaurian "raptors" and will serve us well in our discussion, regardless of whether it's a true taxonomic group or merely a collection of anatomically similar, but unrelated species.

Secondly, a qualifier on the word "raptor". While "raptor" has been synonymous with "birds of prey" for about two centuries, it has increasingly been used to refer to dromaeosaurids and similar non-avian dinosaurs since the Jurassic Park franchise introduced it as shorthand for Velociraptor (see Farquhar 2017 for the complex history of this word). While some purists dislike the latter use (myself included, to be honest), technical palaeontological literature has started to adopt "raptor" as a colloquialism for Dromaeosauridae as well. Miserable old-fashioned folks like myself thus need to concede that "raptor" has grown to encompass members of Dromaeosauridae even though this complicates discussions where raptorial birds and dromaeosaurs are mentioned simultaneously. Thus, to avoid confusion, my use of "raptor" here is meant in the traditional avian sense of the word, unless otherwise specified.

These points in place, let's get moving through pop-culture takes on eudromaeosaurs to see how they stand up to scientific scrutiny.

Pop-culture concept. Eudromaeosaur species are basically all the same animal expressed at different body sizes.

It's difficult to mention dromaeosaurs online without discussion turning to the real taxonomic identity of the Velociraptor featured in the Jurassic Park series. Deinonychus and Utahraptor are often mentioned as the actual basis for the animals featured in those films*. These discussions imply that all eudromaeosaurs were generally similar in appearance to Deinonychus or Velociraptor: fairly gracile animals with long-ish limbs, large claws, long tails and low, slender skulls, and that size was their main distinguishing feature.

*It's worth taking a moment to give some additional information on this oft-discussed point. The preface of Robert Bakker's 1995 novel Raptor Red gives a behind-the-scenes insight on this matter, acknowledging that the size of the Jurassic Park Velociraptor was not based on anything other than the desires of the filmmakers, and that their scaling of these animals to sizes beyond those of Deinonychus - the biggest dromaeosaur known until 1993 - was cause for concern among some involved in the film. The Jurassic dromaeosaurs were made vastly bigger than both Velociraptor and Deinonychus because the real size of these animals wasn't considered intimidating enough. The 1993 discovery of Utahraptor, while giving the filmmakers a reprieve for making their dromaeosaurs so big, didn't fully justify their scaling either as this animal was initially thought to be around 7 m long: about twice the size of those in the film (Kirkland et al. 1993). The man-sized Jurassic 'raptors' thus lacked a good size match among Dromaeosauridae in the early 1990s and, in my view, are best viewed as 'generic' eudromaeosaurs shaped to the requirements of the film, rather than being based on any particular genus.

Not all eudromaeosaurs were variants on Velociraptor. Utahraptor ostrommaysorum sits at the other end of their anatomical range, being a large (5-6 m long), 300-500 kg predator with a proportionally large head, stout limbs and enormous claws. It almost resembles a dromaeosaur wanting to revert to a more traditional theropod body plan, without sacrificing some key dromaeosaur adaptations.

A fair degree of anatomical variation has been apparent in Eudromaeosauria since at least the early 1990s, however. Though sharing a similar body plan, eudromaeosaurs differ in attributes of limb length, limb bone proportions, head size, jaw depth, dental configuration, claw sizes, tail flexibility and many other smaller anatomical components (e.g. Turner et al. 2012; Paul 2016). They ranged from smallish animals less than 1.5 m in length and perhaps just 5 kg in weight (Bambiraptor) to grand species some 5-6 m long and exceeding 300 kg (Utahraptor). At least some of these large-bodied species, such as Utahraptor and Achillobator, were stocky, large-headed creatures with deep jaws, heavy hips, stout limbs, large sickle claws, and relatively powerful bites (above). Other giant eudromaeosaurs were not especially robust however, with Dakotaraptor being of similar build to Deinonychus-like morphs despite being one of the largest dromaeosaurs (DePalma et al. 2015). Smaller eudromaeosaurs were also anatomically varied, with genera such as Dromaeosaurus and Atrociraptor bearing short, deep snouts and robust teeth, instead of the long, slender jaws of Deinonychus-like species. Some real oddballs are also known, such as Adasaurus mongoliensis: a smallish eudromaeosaur with a somewhat reinforced posterior skull and a vastly reduced sickle claw (Turner et al. 2012).

The wimpy sickle claw of Adasaurus, as illustrated by Turner et al. 2012.

Although these differences are undeniably small compared to the disparity of theropods as a whole, they would surely be very obvious should we have seen these animals in life. Eudromaeosaurs were not merely differently-scaled variants on Velociraptor, but differently adapted species with a range of functional morphologies and behaviours. Eudromaeosauria was a widespread and long-lived group and these distinctions probably reflect adaptations to the range of prey species, as well as environmental and climatic regimes experienced by its members. We should probably view eudromaeosaurs as having a similar anatomical and ecological range to some living carnivore groups, such as felids or raptorial birds, which range from tiny hunters of small animals to heavyset predators of larger game. As with cats and raptors, those concerned with the accurate conveyance of eudromaeosaur biology have to be careful not to over-generalise details of their anatomy and appearance.

Pop culture concept. Eudromaeosaurs were lightning fast, streaking after their prey at speeds comparable to the fastest living land animals.

The silver-screen Velociraptor of Jurassic Park has, time and again, been shown as an incredibly swift animal. Described as having cheetah-like speed in the first film (which equates to a maximum speed of 109.4–120.7 kph, or 68.0–75.0 mph), we've since seen them running down hadrosaurs in Jurassic Park III and leading jeeps and motorcycles in Jurassic World. These pop-culture depictions align with energetic names and artwork associated with these animals for almost a century. Deinonychus was, of course, a poster child of the dinosaur renaissance and an animal which helped change thinking about dinosaur metabolism and activity rates. Robert Bakker's famous sprinting Deinonychus reconstruction (below, first published in Ostrom 1969) is a famous and influential palaeoartwork demonstrating eudromaeosaurs as fast, agile creatures. The names of classic eudromaeosaur taxa - Dromaeosaurus ("running lizard"), Velociraptor ("fast thief") - emphasise their swiftness and raptorial nature, implying speed and agility above the dinosaurian average.

Bakker's sprinting Deinonychus antirrhopus from Ostrom (1969). Now over 50 years old and dated in many respects, it remains an iconic image of the Dinosaur Renaissance and conveys the important message that dinosaurs - including dromaeosaurs - were fast, powerful creatures.

Perhaps surprisingly given their reputation, studies show that eudromaeosaurs weren't exactly speed-demons. A caveat here is that it's actually pretty difficult to know exactly how fast extinct animals could move because speed is influenced by a range of factors which are challenging to predict reliably from fossils. These include animal mass, muscle fractions, muscle speed, bone strength, stride length and others. Trackways can give an idea of velocity for a given individual - and they are known for dromaeosaurs - but they may not record animals moving at their maximum speeds. We can, however, make decent assessments of extinct animal speed from their limb proportions and by searching for anatomies that are common to fast runners today. From these, we've known for at least half a century that eudromaeosaurs were not among the quickest dinosaurs (Ostrom 1969; Paul 1988; Kirkland et al. 1993; Carrano 1999; Persons and Currie 2016), despite contrary claims in popular works and their treatment in some scientific literature.

What slows eudromaeosaurs down is that, in contrast to cursorial (= fast running) animals, they lack elongated distal limb segments, reduced and streamlined toe anatomy, and narrowed, fused metatarsals. Studies suggest that eudromaeosaur hindlimbs, although clearly well-muscled, sacrificed speed for strong, grasping foot anatomy (Ostrom 1969; Fowler et al. 2011). Biomechanical studies show that appendage strength and running speed are something of an adaptive fork in the road as they exert conflicting demands on muscle distribution, limb length and bone robustness. Close relatives of eudromaeosaurs, including the unenlagiines and troodontids, adapted towards greater cursorial abilities at the expense of foot power and were probably far nimbler, faster creatures than equivalently-sized eudromaeosaurs (Carrano 1999; Persons and Currie 2016).

Eudromaeosaurs were probably not the fastest dinosaurs, but they were lightly built, well-muscled animals that could surely move at a reasonable speed for at least a short amount of time to catch their prey. Here, Velociraptor chases down Zalambdalestes.

This all said, no-one thinks eudromaeosaurs were exactly slowpokes. As generally smallish, lightly built dinosaurs with somewhat elongated and well-muscled hindlimbs, eudromaeosaurs were probably capable of moving quickly at times, just not for sustained periods or at record-breaking speeds. Their stiffened tails are clear hallmarks of rapid locomotion, being ideally suited to facilitating quick changes in direction at speed (Ostrom 1969; Persons and Currie 2012). It seems reasonable to assume that eudromaeosaurs were adept at ambushing prey, relying on a short burst of speed and agility to catch fleeing animals from a covered position, but that target species might have had an advantage if a long pursuit was involved.

Certain eudromaeosaurs, such as the large-bodied Utahraptor, were probably not especially quick animals, however. Their hindlimb proportions are even less suited to running than other eudromaeosaurs and their tails were not significantly stiffened, suggesting lessened agility as well as speed (Kirkland et al. 1993). Judging from their proportions, it looks like these species compromised their running capabilities to facilitate greater body mass, hindlimb power and head size. Hopefully, as we learn more about these very large eudromaeosaur species we'll develop more insights into their locomotion.

Pop culture concept. Eudromaeosaurs had tremendously strong bites.

An idea popularized in at least the Jurassic Park novel is that eudromaeosaurs, in addition to being blade-wielding superninjas, were also armed with a bite that would make an alligator feel inadequate. In this book Velociraptor literally chews through steel bars in a noble but ultimately futile effort to kill one of fiction's most irritating characters, Ian Sodding Malcolm. While this doesn't seem to be a particularly widespread popular assumption about eudromaeosaurs, responses to the Beau vs. dromaeosaur tweet certainly included a few comments about powerful bites.

Terrifically preserved skull of Velociraptor mongoliensis showing the low, narrow, lightly built skull construction typical of most eudromaeosaurs. These are not the skulls of powerful biters, but of lightweight, fast-moving animals with teeth suited to rapid tearing of flesh. From Turner et al. (2012).

Dromaeosaur bite strength is something that we've addressed on this blog before so I won't dwell on it long here. Deep bite marks on a Tenontosaurus fossil have been attributed to Deinonychus and promoted as evidence for a powerful, alligator-grade bite in this genus by one set of authors (Gignac et al. 2010), but virtually all other studies conducted on the skull strength and bite forces of eudromaeosaurs have drawn conflicting conclusions (Therrien et al. 2005; Sakamoto 2010; Fowler et al. 2011). Eudromaeosaur skulls are generally lightweight structures composed of thin bars and sheets of bone, and were thus poorly suited to powerful biting. In all likelihood, those Tenontosaurus bones were bitten by another animal. Therrien et al. (2005) predicted the bite force of Deinonychus as being comparable to that of a 30 kg wolf, a value which seems impressive until we remember that Deinonychus was about twice that size (c. 80 kg). This difference likely reflects the fact that canids are adapted for chewing into bone, while eudromaeosaurs have the slender teeth and relatively delicate jaws of dedicated flesh-eaters. They surely ate around or swallowed skeletal elements whole so as not to damage their teeth chewing into bones. Thus, while it would not be wise to put your hand in a eudromaeosaur's mouth, there are plenty of other animals out there that could bite you harder. An unknown quantity here is how powerful the bite of something like Utahraptor was: there is good reason to think these animals had large, relatively strong skulls that may have allowed for greater bite forces, but we need more substantial fossils of these giant dromaeosaurs to understand their bite performance.

Pop culture concept.Eudromaeosaurs attacked their prey with razor-sharp claws, slicing deep into their flesh to leave long, bloody lacerations.

The eudromaeosaurs I knew from my childhood dinosaur books - both educational and fiction - were imagined as having ferociously sharp claws which could be deployed in an especially gory, grotesque fashion to dispatch prey. Palaeoart fans will not need to be reminded of the glut of 1990s dinosaur art showing this: swarms of dromaeosaurs using their claws to clamber over prey species, tearing into their hides to leave long, deep gashes. I have no doubt that these predatory scenarios were a major part of why dromaeosaurs became a firm favourite among dinosaur fans and the public alike. My own childhood sketchbooks were certainly full of bloody, gory dromaeosaur art inspired by these ideas.

Page from the 1993 comic serial Age of Reptilesshowing Deinonynchus bringing down a sauropod with slashing, razor-sharp claws. Though portrayed in a comic book, this is pretty close to how dromaeosaur claw function was predicted by scientists in the early 1990s. Art by Ricardo Delgado, borrowed from Dark Horse Comics.

Flesh-ripping dromaeosaur claws have some actual basis in science, this being the accepted interpretation of sickle and hand claw function in the mid to late 20th century (e.g. Ostrom 1969; Bakker 1986, 1995; Paul 1988; Kirkland et al. 1993). Their deep, bladed nature and large flexor tubercles (the part of the claw anchoring flexing musculature) of dromaeosaur hand and sickle claws give this idea some credibility, and the size of most eudromaeosaurs claws is undeniably remarkable: there's no doubt that they were paramount to their predatory behaviour.

However, this concept has come under fire in recent years as we've started to assess the lifestyles of eudromaeosaurs in a more detailed and biomechanics-led fashion. It's quite well established, for instance, that while dromaeosaur claws are narrow, they aren't quite knife-like enough to facilitate easy cutting of skin and muscle tissue. Their cross-sections are somewhat like a stretched, inverted pear (below) with a narrow but distinctly rounded inner margin (Carpenter 2000; Farlow et al. 2011). It is also unlikely that their claws were shaped into razor-like cutting edges by keratinous sheaths, unless they had a sheath-claw bone relationship unlike anything seen in birds and reptiles today (Carpenter 2000; Manning et al. 2006). These are major problems for the slashing hypothesis because, as many of us know from personal dining experiences, it can be challenging to cut animal skin and flesh without a well-sharpened blade (Carpenter 2000). That dromaeosaurs could hone and maintain a razor-like claw edge against routine abrasion and wear is a naive assumption: claw tips can be sharpened by the removal of abraded and ragged sheath layers (as the trashed furniture of many cat owners will attest) but it's harder to hone the edge of an entire claw without dedicated technology (Carpenter 2000).

Eudromaeosaur claw shape as illustrated by Carpenter (2000). Note the width of the claws and lack of bladed cutting edges along their inner margins.

A further problem for the slashing hypothesis is the amount of force eudromaeosaurs could transmit to their sickle claws during kicks or other attacks with extended legs. Many of us are familiar with artwork of aggressive dromaeosaurs posed in this way, but it turns out that outstretched legs are actually the weakest configuration for application of claw force (Farlow et al. 2011; Bishop 2019). Eudromaeosaur hindlimbs actually delivered a lot more power through their sickle claws when the leg was crouched or otherwise flexed (Fowler et al. 2011; Bishop 2019) and, perhaps surprisingly, the overall force achieved at the claw tips was not great relative to the strength of prey animal tissues (Manning et al. 2006; Bishop 2019). Thus, even under optimal conditions, it's unlikely that eudromaeosaurs had sufficient strength to create long, deep wounds in animal flanks. Neither claw shape nor our understanding of hindlimb mechanics corroborates the use of eudromaeosaur claws as ripping and slashing structures.

A counterargument to this might be the commonality of foot slashing behaviour by sparring birds. Many avian species, including those with formidable claws for raptorial or perching behaviour, kick and slash at each other when settling disputes in a manner not entirely unlike that traditionally predicted for predatory dromaeosaurs. Might not similar movements, scaled up to the size of large eudromaeosaurs, have been effective means to bring prey down? In my mind, the behaviour of modern sparring birds might actually be further evidence against claws inflicting major injury through kicking actions. In all but the most serious bouts - where slashing and kicking turns to wrestling, pecking and eye-gouging, or where circumstances do not allow for escape for a weakened bird - avian sparring rarely leads to more than superficial injuries. In some species, including those with large talons and curved claws like eagles and seriemas, talon clashing is even employed in non-aggressive acts such as courtship and between parents and juveniles (e.g. Silva et al. 2016). The fact that birds can endure kicks from clawed feet without great concern is further evidenced by brutish humans equipping cockfighting roosters with artificial spurs - metal blades and so on - to allow them to inflict deeper, more critical wounds when sparring**. Though not a perfect analogue for eudromaeosaur slashing predation, these avian behaviours demonstrate that simply having large claws on powerful legs does not turn animals into deadly bladed assassins, and seemingly concurs with the predicted weak performance of claws in kicking or slashing. There's more to say on how dangerous bird claws can be when employed aggressively, and we'll return to this topic in the next article.

**In what might be seen as poetic justice, the addition of artificial spurs to fighting chickens turns them into animals that are also deadly to humans. At least three peoplehave been recorded as dying after attacks or accidents involving sparring cockerels with razors added to their legs.

The flexed left foot of Deinonychus as illustrated by Fowler et al. (2011). I find this image absolutely compelling evidence of the powerful grip provided by these feet in life, and more than a little intimidating. Note the lateral flexion of the fourth toe afforded by the ball and socket-like joint at the end of the metatarsal. Scale bar is 100 mm.

So if they weren't for cutting and tearing, what were eudromaeosaur sickle claws for? A breakthrough interpretation of their function has stemmed from realising that we should focus on eudromaeosaur feet as a whole, and not just the impressive sickle claws on digit II (Fowler et al. 2011). Armed with this perspective, it becomes apparent that their whole foot structure is well adapted to piercing and powerful gripping. Their claws are mechanically strong against the forces associated with puncturing skin (Manning et al. 2009) and, although ill-suited to ripping flesh, physical modelling implies a great ability to dig into and hold bunched animal tissues (Manning et al. 2006, though see Fowler et al. 2011 for a critique of this research). Articulating well-preserved eudromaeosaur feet shows that they could form a formidable-looking 'fist' in which the middle toes (the sickle claw and digit III) clenched tightly in line with the long bones of the foot, and the lateral toes (the hallux, and a relatively mobile fourth digit) gripped from opposing sides (Fowler et al. 2011). This gripping function benefits enormously from the short, wide and unfused metatarsus of the eudromaeosaur foot as this provides room for multiple strong ligaments and gives a robust, strain-resistant base to the clenching digits. Presumably, this gripping adaptation is the payoff for reduced eudromaeosaur running speed (Fowler et al. 2011). An ability to form a tight fist with the foot is shared with many living raptors, and studies have found numerous hitherto unappreciated similarities between the feet of these species, with eagles among the best modern analogues (Fowler et al. 2009, 2011).

This revelation that dromaeosaur feet are more about gripping than slashing has important implications for how we imagine the ecology of these animals, and suggests many of our traditional concepts of eudromaeosaur prey apprehension are unlikely. It seems that the formidable claws of these animals were not quite the be-all and end-all of eudromaeosaur predation that we once thought, and that they were instead part of a prey immobilisation strategy that involved their entire bodies. Exactly what that predatory strategy might have been is something we'll get to in the second part of this series.

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References

• Bakker, R. T. (1986). The dinosaur heresies. William Morrow.
• Bakker, R. T. (1996). Raptor red. Bantam.
• Bishop, P. J. (2019). Testing the function of dromaeosaurid (Dinosauria, Theropoda) ‘sickle claws’ through musculoskeletal modelling and optimization. PeerJ, 7, e7577.
• Carpenter, K. (2000). Evidence of predatory behavior by carnivorous dinosaurs. Gaia, 15, 135-144.
• Carrano, M. T. (1999). What, if anything, is a cursor? Categories versus continua for determining locomotor habit in mammals and dinosaurs. Journal of Zoology, 247(1), 29-42.
• DePalma, R. A., Burnham, D. A., Martin, L. D., Larson, P. L., & Bakker, R. T. (2015). The first giant raptor (Theropoda: Dromaeosauridae) from the hell creek formation. Paleontological Contributions, 2015(14), 1-16.
• Farquhar, C. C. (2017). Commentary: Raptor—Evolution of the Term. Journal of Raptor Research, 51(2), 172-179.
• Fowler, D. W., Freedman, E. A., & Scannella, J. B. (2009). Predatory functional morphology in raptors: interdigital variation in talon size is related to prey restraint and immobilisation technique. PloS one, 4(11).
• Fowler, D. W., Freedman, E. A., Scannella, J. B., & Kambic, R. E. (2011). The predatory ecology of Deinonychus and the origin of flapping in birds. PLoS One, 6(12).
• Gignac, P. M., Makovicky, P. J., Erickson, G. M., & Walsh, R. P. (2010). A description of Deinonychus antirrhopus bite marks and estimates of bite force using tooth indentation simulations. Journal of Vertebrate Paleontology, 30(4), 1169-1177.
• Kirkland, J. I., Gaston, R., Burge, D., Kirkland, J. I., & Burge, J. D. (1993). A large dromaeosaur (Theropoda) from the Lower Cretaceous of eastern Utah. Hunteria, 2, 1-16.
• Manning, P. L., Payne, D., Pennicott, J., Barrett, P. M., & Ennos, R. A. (2006). Dinosaur killer claws or climbing crampons?. Biology Letters, 2(1), 110-112.
• Manning, P. L., Margetts, L., Johnson, M. R., Withers, P. J., Sellers, W. I., Falkingham, P. L., ... & Raymont, D. R. (2009). Biomechanics of dromaeosaurid dinosaur claws: application of X‐ray microtomography, nanoindentation, and finite element analysis. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology: Advances in Integrative Anatomy and Evolutionary Biology, 292(9), 1397-1405.
• Ostrom, J. H. (1969). Osteology of Deinonychus antirrhopus, an unusual theropod from the lower Cretaceous of Montana. Peabody Museum of Natural History, Yale University Bulletin, 30, l65.
• Paul, G. S. (1988). Predatory dinosaurs of the world: a complete illustrated guide. Simon & Schuster.
• Paul, G. S. (2016). The Princeton field guide to dinosaurs. Princeton University Press.
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• Sakamoto, M. (2010). Jaw biomechanics and the evolution of biting performance in theropod dinosaurs. Proceedings of the Royal Society B: Biological Sciences, 277(1698), 3327-3333.
• Silva, A. N., Nunes, R., Estrela, D. C., Malafaia, G., & Castro, A. L. (2016). Behavioral repertoire of the poorly known Red-legged Seriema, Cariama cristata (Cariamiformes: Cariamidae). Rev. Bras. Ornitol, 24, 73-79.
• Therrien, F., Henderson, D. M., & Ruff, C. B. (2005). Bite me: biomechanical models of theropod mandibles and implications for feeding behavior. The carnivorous dinosaurs, 179-237.
• Turner, A. H., Makovicky, P. J., & Norell, M. A. (2007). Feather quill knobs in the dinosaur Velociraptor. Science, 317(5845), 1721-1721.
• Turner, A. H., Makovicky, P. J., & Norell, M. A. (2012). A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American museum of natural history, 2012(371), 1-206.

Some marine reptiles - like Shonisaurus popularis - were big. So big, in fact, that you can't fit them all into a picture. But just how large did the largest marine reptiles get? Finding the answer can be more involved than you'd think. This image is a cropped version of a larger picture, which you can see at my Patreon.

The size of Mesozoic marine reptiles is undeniably a big part of their charm and popular appeal. And yet, if you want to know how big some of these animals really got - and by 'really', I mean 'size estimates preferred by contemporary scientists based on our latest data' - you might have a struggle on your hands. Marine reptile media is full of varying size estimates for different groups, some of which are accurate to modern science, some of which were accurate to old science, and many of which were never accurate to begin with. It's not always easy to tell which is which.

I've recently had cause to ascertain reliable size estimates for a number of marine reptile clades and found it far more involving than I anticipated, especially for pliosaurids and ichthyosaurs. This isn't necessarily because it's hard to find an article or paper giving figures of total length or mass, but because confused taxonomies, a deficit of complete skeletons and opaque comments in technical literature complicate efforts to recover and understand maximum size estimates from peer-reviewed, reliable sources. I thought it might be of interest to share some of my findings here, focusing specifically on those two aforementioned groups - pliosaurids and ichthyosaurs - as I feel their upper size range is perhaps most in need of clarification.

Before we get going, it's worth reminding ourselves of how estimating the size of very large extinct individuals is fraught with challenges, and how the numbers and stats we throw around are often based on relatively little data. Many well-known scaling problems apply to ichthyosaurs and pliosaurs. Our remains of especially large individuals are not only rare but are often relatively scrappy, and our capacity to scale reliably from other, smaller animals is frequently more limited than we might like. As is often necessary, there's a need to distinguish between size estimates that are generally reliable, being based on relatively complete large skeletons, and those which are only indicative, on account of being scaled from fragmentary remains. At the risk of spoiling details of the article below, there doesn't seem to be a clear answer to "what's the biggest pliosaurid" or "what's the biggest ichthyosaur" because the size estimate error bars for most very large specimens are too wide to give precise assessments.

Giant pliosaurids

The great size of certain Late Jurassic and Lower Cretaceous pliosaurids has made them famous, perhaps especially so in the UK and Australia where giant animals are particularly well represented. Since their discovery in the mid-19th century, there has been no doubt that certain pliosaurids attained enormous sizes and dwarfed virtually all other organisms in their respective palaeoenvironments (e.g. Owen 1841; Longman 1924; Tarlo 1959).

How the world met pliosaurids: plate 68 of Owen's Odontography (1841). That's a life-sized Pliosaurus tooth at the bottom of the page. Note the spelling - "Pleiosaurus". It's not clear why Owen changed the name later, but "Pleiosaurus" has not been widely used since the 1840s and Pliosaurus has, by rules of zoological nomenclature, won out.

Newman and Tarlo's (1967) unnamed pliosaurid reconstruction, interpreted by McHenry (2009) as the 10 m long Pliosaurus macromerus (a species of uncertain validity today - see Knutsen 2012 vs. Benson et al. 2013) or Liopleurodon ferox, based on a near-complete, 4.88 m long specimen held in Tübingen, Germany (Noè 2001). I like the generous soft-tissue outline of this illustration - it looks appropriately bulky and well-muscled.

Famously, 1999 saw claims of whale-sized pliosaurs take root in public conscience courtesy of the BBC documentary Walking with Dinosaurs. The antagonist of the Jurassic marine-focused third episode was a 25 m, > 100-tonne Liopleurodonferox which was, even given the general uncertainty about pliosaur size, a very controversial reconstruction for a species only known from much smaller remains. Our largest Liopleurodon skull (discovered in the early 20th century, so known to the producers of the programme) is 1.54 m long (Benson et al. 2013) so, assuming a skull:body length ratio of about 1:5 (Noè et al. 2001; McHenry 2009), we can predict that large Liopleurodon individuals were about 8 m long. How did this value become tripled for the documentary? Writing in 2000, two of my colleagues - David Martill (my PhD supervisor, also a consultant for WWD) and a pre-TetZoo Darren Naish explored the rationale of this decision:

This size created much debate in palaeontolgoical circles following the first airing of the programme, as no palaeontologist thinks Liopleurodon really got this big.

Although several complete [Liopleurodon] skeletons have been discovered, these are of individuals of between five and ten metres in length. It is less complete remains discovered in the Oxford Clay that indicate lengths greater than this, though here we move into an area of rough estimates and guesswork. A vertebra at the Peterborough Museum, brought to light in 1996, would seem to indicate a pliosaur of between seventeen and 20 metres in length, and various fragments of snout and lower jaw in other museum collections suggest specimens of similar size. Whether these fragments are actually from Liopleurodon is uncertain, and the animal to which they belonged has been nicknamed 'Megapleurodon'. Given that it is unlikely that these bones really represent the very biggest pliosaur specimens that ever lived, some experts cautiously suggest that Liopleurodon and related forms may have achieved total lengths of around 25 metres.

Unfortunately for those excited by the idea of a whale-sized pliosaurid, the specimens touted as rationalising the WWD monster have not delivered on their promise. In what is perhaps the most detailed assessment of maximum pliosaurid size conducted to date, Colin McHenry (2009) discussed all the fragmentary material from Britain and Mexico linked with supersized pliosaurids and found that they represented very large animals, but not whale-sized giants. Colin confirmed that the vertebra housed at Peterborough Museum was indeed very large - 252.5 mm wide by 219 mm tall - but its total body length estimate was just 11.6–14.2 m when scaled to well-known pliosaur remains. A large Jurassic mandibular symphysis archived in the Natural History Museum, London might represent an animal anywhere between 9.1 and 15.1 m long, while OUM J.10454, a near-complete, 2.8 m long lower jaw dubiously referred to Pliosaurus macromerus and known informally as the 'Cumnor mandible', scales to a surprisingly low 12.7 m. In subsequent years this estimate has also become questionable as we've realised how reconstructed the Cumnor mandible is: it remains to be determined what size range the original specimen represents (Benson et al. 2013).

The Tübingen University specimen of Liopleurodon ferox, a near-complete 4.8 m long juvenile. This is a key specimen for our understanding of Jurassic pliosaur proportions, and thus the size of the biggest individuals. From Wikimedia user Ghedoghedo, CC BY-SA 3.0.

The same story plays out across all other giant pliosaurid fragments, including the Mexican Monster of Aramberri. It seems that when scaled using our best data on pliosaurid proportions and growth allometry, most 'giant' pliosaurid fossils return total length estimates in the 10 m range, with only the upper bounds of our least reliable length estimates falling outside this (McHenry 2009). There's perhaps a moral here about reading too much into the size of giant but fragmentary bones. As stated by McHenry (2009):

Estimates made on incomplete series of vertebrae, or even a single vertebrae, are subject to the natural variation of vertebral dimensions and should be used with caution. The dimensions of individual vertebrae can be affected by taphonomic processes, in particular sedimentary compaction, and when size estimates are extrapolated from single
elements small errors can be greatly magnified. The same applies to any allometric variation than is not accounted for in scaling models... any estimates based upon more complete pliosaurid material requires extrapolation over at least an order of magnitude of body mass, a leap that means even small errors in the estimate of allometric or intraspecific variation will produce a large range of results.

My take on one of the largest Jurassic pliosaurids, Pliosaurus kevani. It was probably about 10 m long, assuming similar proportions to other pliosaurids. The smaller animal above is a calf.

So, putting the ideas of gigantic pliosaurs to the side, what are our most reliable estimates for the maximum sizes of these animals? Detailed assessments of the very large and relatively well-known pliosaur Kronosaurus queenslandicus suggest that a total length of 10.5 m and a mass of 11 tonnes is likely (McHenry 2009). Kronosaurus is one of the few large pliosaurids known from decent and articulated postcranial remains so this figure involves minimal extrapolation, and should be regarded as one of our more reliable insights into the maximum size of these animals. It seems that c. 10 m is about right for other large pliosaurids, too. The skulls of large Kronosaurus are 2.3 m long, a value comparable to measured and estimated skulls lengths of the largest Jurassic pliosaurid, Pliosaurus (2-2.5 m; Knutsen et al. 2011; Benson et al. 2013). If pliosaurid skulls account for roughly 20% of their body length, these are on target for a Kronosaurus-like size of 10 - 12.5 m. While that upper range is obviously higher than Kronosaurus, we shouldn't put much stock in it yet. Our 12.5 m Pliosaurus is a body length extrapolation based on a rough skull size calculation, and both these values hinge on the specimen in question having the same skull and body proportions as other, mostly non-Pliosaurus pliosaurids. Our 12.5 m Pliosaurus is thus perched on a stack of assumptions, each one compounding any errors of the one beneath it. Such methods are fine for getting ballpark size figures but they are far from precise and we should treat them with appropriate caution. Greater understanding of the size of the biggest pliosaurs will require discovery of more substantial skeletons of large pliosaur individuals.

Giant ichthyosaurs

It's remarkable to me that the giant ichthyosaurs, which are without doubt the largest marine reptiles of all time, appeared in the Late Triassic - just a few tens of millions of years after marine reptiles entered the seas. Ascertaining details of how large these animals got is complicated but not, as with pliosaurs, because of scant remains. To the contrary, we actually have several excellent fossils of very large ichthyosaurs (Camp 1980; Kosch 1990; McGowan and Motani 1999; Nicholls and Manabe 2004), and our challenge is instead related to working out what taxa they represent. The history of two ichthyosaur genera associated with giant size - Shastasaurus and Shonisaurus - is complex and intertwined. While there's no doubt that Shonisaurus contains at least one species of very large ichthyosaur (Sho. popularis), it's not always been clear whether Shastasaurus also contained giant animals, nor to which of these genera the largest ichthyosaur remains should be referred to. The confused treatment of these animals in technical literature has spread into the popular realm and it's very easy to find articles and art treating Shastasaurus and Shonisaurus interchangeably. This is unfortunate because, as we'll see, they're actually very different animals.

A 2020 take on some dinosaur or another. I forget its name. This individual has recently gorged itself, resulting in a distended belly and sleepy demeanour.

Unless you've been living under a rock for the last fortnight you cannot have escaped news on one of the most famous and controversial of all dinosaurs: Spinosaurus aegyptiacus. The appearance of Spinosaurus has once again transformed via the discovery of new fossils unearthed from the Late Cretaceous Kem Kem beds of Morocco: chiefly, a long paddle-like tail of superficially newt or crocodylian-like flavour. Keen interest in Spinosaurus, as well as a large National Geographic-led PR campaign for the new study, has seen social media awash with discussion about the new discovery, and illustrations of the latest in spinosaurine fashion have swamped online galleries since. As Chris Dipiazza eloquently explained on Twitter, it hasn't been the best two weeks if you aren't a Spinosaurus fan.

Floating spinosaurids from Henderson (2018). One of the take-homes from Don's work is that Spinosaurus did not have an unusual floating posture among theropods, and that theropods were, in general, capable of floating with their heads well clear of the water to breathe. This questions whether features of the Spinosaurus skull linked to aquatic lifestyles - like the position of the eyes and nose - were specific adaptations to aquatic lifestyles.

I don't want to pretend that I know which of these arrangements is correct. Arranging these vertebrae is complicated, and there are multiple, perhaps equally viable ways we can order them at present. Based on the new tail data, I suspect the interpretation of Stomer and Ibrahim et al. are correct in restoring the sail plunging sharply into the tail base, but I also see merit to Stomer's 1936 model where vertebra 'f' - the cause of the dip in the Ibrahim et al. model - is positioned more anteriorly.

Tail flexion

The new tail of Spinosaurus, as presented by Ibrahim et al. (2020b). Note the reduction of musculature in the distal tail ('e') in relation to the discussion of bone bending, above.

Facial anatomy and lips

To close out this post, I want to briefly touch on a topic not directly covered in the recent Spinosaurus work, but that comes up whenever spinosaurid illustrations are discussed: did these animals have lipless, crocodylian-like faces? In my experience, lipless spinosaurids are justified by several lines of evidence: their superficially crocodylian-like jaws and teeth; the size and configuration of their anterior teeth (where large premaxillary teeth overbite the lower jaw and long dentary teeth - unusually for a theropod - protrude over the upper jaw during occlusion; Dal Sasso et al. 2005), and the development of liplessness in other semi-aquatic fishers, such as crocodylians and river dolphins.

The recent Black Lives Matter protests resulting from the cruel murder of George Floyd at the hands of US police officers have once again drawn attention to matters of racial inequality around the world. These events have been, for me, a belated eye-opener to the depth of institutionalised racism experienced by non-whites internationally, especially by black people. Like many white folks, I have traditionally assumed that simply not being racist was doing my part, and that the actions of others would eventually convert society at large to seeing race as the non-issue it should be. I have also felt that, as a white, straight male from a middle-class background, my voice would add nothing to this conversation or - worse - be seen as patronising or virtue signalling.

I now realise that this view was incorrect. The fact that people of colour are still fighting against global systemic marginalisation and persecution shows that being non-racist isn't enough, and that we must be outspokenly anti-racist,even if we have never experienced racial discrimination ourselves. Some may accuse me of jumping on a bandwagon with this. That's accurate, but I don't care. This is a wagon we should all be on, and I'm ashamed for not being on-board earlier.

In reflecting on racial issues for much of this week, it's been difficult to escape how prevalent racism is in Western culture once you open your eyes to it. Even palaeoart, which outwardly seems like an entirely innocent endeavour largely uncomplicated by social conventions, has been tainted. Palaeoart has actually been associated with suppression of non-white people both indirectly and rather pointedly, and not through obscure works or people, either. Famous historic figures, who are justifiably held in high regard for their scientific and palaeoartistic work, are part of this story. We're talking about people like pioneering European scientists - George Cuvier and Henry de la Beche - as well as pivotal American figures - Edward Drinker Cope, Charles Knight and Henry Fairfield Osborn - actively benefitting from black oppression or contributing to the thoroughly debunked pseudoscientific field of biological racism (the attempted justification of racist views with scientific study). The racist history of palaeoart thus hides in plain sight, and the fact that this seemingly innocuous branch of natural history illustration has this darker side is a great example of how rooted prejudice is within Western culture.

The first true palaeoart scene, Duria Antiquior, by geologist, palaeoartist and slave owner Henry de la Beche.

Three of the above-mentioned figures did not outwardly produce racist palaeoart, but strongly promoted or benefitted from racism against black people in other facets of their lives. Cuvier, who produced some of the first musculoskeletal reconstructions of fossil animals and was among the first to publish animal life reconstructions in academic works, viewed whites as the pinnacle of creation, but blacks as ugly, barbaric persons of monkey-like appearance. His work on dividing humans into 'scientifically validated' races was instrumental in later attempts at biological justifications of racism. De la Beche, famous for producing the first palaeoart scene in 1830, Duria Antiquior, owned a Jamaican slave plantation and was against the abolition of slavery. Cope, who drafted some of the first American palaeoart and mentored Charles Knight in the anatomy of prehistoric animals for a short period, wanted to see black people returned to Africa, and viewed them as degenerate forms of humans with animalistic levels of self-control.

The majority of the Henry Fairfield Osborn-directed Charles Knight mural Neanderthal Flint Workers (1924) - the right side of the image shows a valley and Coelodonta which is missing from this cropped version. This mural was hung in the AMNH's Hall of Man, an exhibition which included content based around Osborn's racist and eugenicist ideas. The 'primitive' look of these Neanderthals was not deduced from their bones, but based on features of non-white peoples that Osborn regarded as inferior to white Europeans.

Knight and Osborn, however, produced palaeoart that was genuinely racially offensive. It's not clear to me what Knight's views on race were*, but Osborn's racism, eugenicism, his support of Hitler, and his exploitation of his presidency at the American Museum of Natural History to research and promote his racist agenda, are well-documented historical facts. It was under Osborn's direction that Knight produced many now-iconic artworks of prehistoric animals in the late 19th and early 20th century but, while dinosaurs and fossil mammals can be restored without overt social agenda, Osborn's racism was captured in oils when it came to producing art for the AMNH's Hall of Man in the 1920s. Osborn viewed white Europeans as occupying a particularly high branch at the top of the evolutionary tree, with other races and hominid species well inferior. His Hall of Man exhibition sought to present the same view to the public, despite its lack of traction among his scientific peers. Neanderthals were thus shown as much more primitive, both culturally and anatomically, than modern humans, and Osborn ordered them to be restored as brutish and ape-like in Knight's famous Hall of Man mural, Neanderthal Flint Workers. But rather than pointing to apes or monkeys for 'primitive' anatomical references, Osborn pointed to non-white races that he regarded as inferior for details of skin colour and physique. The symbolism here is as gross as it is obvious, and makes the Osborn/Knight Neanderthals the palaeoartistic equivalent of golliwogs, minstrels and mammy figurines. Although this work was controversial among museum staff even when it was produced, and was removed in the 1960s out of recognition of its racist connotations, it remains an iconic, oft-used and oft-referenced illustration even today. Indeed, most popular depictions of Neanderthals are variants on this image: a dark-skinned, black-haired brutish caveman. How many artists, cartoonists and film directors know that their cavemen or Neanderthal depictions are a visual representation of eugenics and racism?

*Passages in Knight's book Prehistoric Man: The Great Adventurer (1949) suggest he shared Osborn's ideas that modern humans evolved in central Asia and not in Africa, and show that he viewed some non-Western cultures as 'primitive', but I'm not aware of any more pointed statements aimed at people of colour.

These are just a handful of easily researched examples of racism touching historic palaeoart, but there are more - particularly in depictions of human evolution. I will be accused of wanting to censor or vilify the figures mentioned above, so want to stress that this is not the point of this piece. The historic significance of these individuals and their contributions to science remain unchanged regardless of their personal views, and I don't regard it as fair to judge people living centuries ago, under very different social norms, by modern standards. Recognising and respecting the objective historic importance of their work is not the same as condoning their racist views. This said, I do condone the retiring of offensive works, such as Neanderthal Flint Workers, and believe that we should not shy away from discussing the racist views of key figures in the history of palaeontology. This is especially so for Osborn-like individuals, who had professional lives strongly influenced and guided by racist agendas.

I'm not sure what good discussing the above will do, but feel that saying something, and acknowledging the sometimes sketchy history of the discipline I work in, is important. It's an opportunity for folks like myself, who have never known the difficulties or prejudice, to say that we're listening, that we understand where we've gone wrong in the past, and that we stand with other races in their quest for fairer treatment and representation. The fact that racism has even touched and shaped palaeoart, a field which I think should be free of agenda and discrimination, is unnerving and sobering to me, especially since it involved artists and scientists who laid down its foundations. Some of the people we've discussed here are personal heroes of mine. And lest we forget, palaeoart is primarily an educational tool, and yet we've seen - via Neanderthal Flint Workers - how it can be corrupted not to show ancient realities, but to promote racist agendas. This is why Black Lives Matter is such an important movement, even if we are not black ourselves: we all have to reflect on the historic and modern ubiquity of anti-black racism if we want to stamp it out.

I began this post with an admission that I have arrived late to this cause, so want to end on a more positive and proactive note, by stating what I intend to do moving forward. I mention this in the hope that it will inspire similar action in others. Firstly, I will be making sure that my future public lectures on palaeoart acknowledge the human cost of early palaeoartworks. I will not be derailing my talks into anti-racist events, but it's nothing to point out that 19th century science had links with slavery and attempted to scientifically prove the inferiority of black people. We shouldn't just let that slide.

Secondly, I intend to obtain a deeper understanding of the pseudoscience of biological racism as well as the recent history of racism in Western nations. I have books on these topics lined up to listen to while working on art projects over the next few weeks - audiobooks being the most effective way for me to digest long reading material, as I rarely get enough time to read traditional books cover-to-cover. I especially want to know more about racism in the UK, as it remains a huge issue, but does not always get the attention it deserves.

Finally, I am also already taking a more active role in standing up to racism in online communities in an effort to provide a better online experience for people of colour. This includes taking a firm line on excluding racists from my social media. Blocking racist accounts, reporting and deleting offensive comments and calling out racism should be the norm in any decent community, but social media groups I'm part of are often surprisingly lenient on overtly racist commenters, even when their guidelines suggest otherwise. It's important to curate communities where people of any skin colour can enjoy themselves unharassed, and asking people to respect their fellow humans is a small price for engaging with their favourite scientists, artists and science communicators. Remember, our online platforms are not democracies: we get to call the shots about what is acceptable.

These are minor steps, but they are a start. Again, I'm not entirely sure what I hope to achieve with this post - perhaps it's simply a cathartic act to express and organise my recent thoughts on this topic. But I hope in sharing this that it inspires some good elsewhere, or at least shows one more supporting voice for a worthy cause.