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Friday, 30 August 2019

We need to talk about teratorns

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.

Teratornithids occupy an unusual status in popular palaeontological culture. They are legitimately popular animals, but fundamental aspects of their palaeobiology are poorly known to non-specialists. Indeed, it’s accurate to say that the two things most people ‘know’ about teratornithids - 1) that they were enormous, 7-8 m wingspan giants and 2) that they lived as condor-like scavengers - conflict with modern interpretations of their palaeobiology. There's clearly a need to bring folks up to speed on what science actually thinks about these awesome but frequently mischaracterized fossil birds, and that's what I aim to do here.

1) No, teratornithids were not the largest flying birds (at least, in terms of wingspan)

Teratornithids were large animals which routinely attained sizes beyond those of living fliers. Even the moderately-sized Teratornis merriami likely massed around 14 kg (Chatterjee et al. 2007), a figure comparable to masses of the largest modern flying birds, and upper size estimates for Argentavis are staggering: up to 6-8 m wingspans and body masses of 65-120 kg (Palmqvist and Vizcaino 2003; Chatterjee et al. 2007). If these estimates are correct, Argentavis was the largest flying bird we know of by a comfortable margin. The only birds rivalling it, the pelagornithids, have comparable 6-7 m wingspans but only 16-40 kg body masses (Mayr and Rubilar-Rogers 2010; Ksepka 2014). These predictions of Argentavis size have shaped our understanding of its flight and ecology. Generally assuming a 70-80 kg mass and 6-7 wingspans, several authors have suggested that Argentavis could only launch under favourable conditions and relied on strong winds for soaring flight (e.g. using downward slopes and headwinds - Campbell and Tonni 1981; Vizcaíno and Fariña 1999; Chatterjee et al. 2007). Vizcaíno and Fariña (1999) presented calculations of Argentavis energetics, range and ecology based to these size estimates and concluded that only a scavenging lifestyle could sustain such enormous birds.

It’s paramount to ask, therefore, how reliable these mass and wingspan predictions are. Argentavis, after all, is only known from a few limb bones, some shoulder material and a lower jaw, and this means we're extrapolating data from other birds to get our size estimates. We should probably tackle this question in two parts.

Like many large extinct fliers, we don't have a great skeletal inventory for Argentavis magnificens. This means that any size predictions of this species are just that - predictions - and only as reliable as the assumptions they're based on. For those very large Argentavis wingspan estimates, that's a critical point. Argentavis skeletal from Chatterjee et al. (2007), white bones are known elements. I'm pretty sure that this figure is an (uncredited) mash-up of teratornithid skeletals by Greg Paul (2002).
Firstly, those 7-8 m wingspan estimates are definitely looking shaky. It’s difficult to know what the skeletal wingspan of Argentavis was as we do not have any complete wing bones but, using a projected humeral length of 57 cm, Mayr and Rubilar-Rogers (2010) regressed a surprisingly small wing spread of just 366 cm. This is way under the 4-5 m skeletal spans measured for some Pelagornis species and an immediate red flag for those 7-8 m Argentavis wingspan estimates. To attain such sizes Argentavis would need primary feathers reaching unprecedented lengths of 1.5-2 m (Chatterjee et al. 2007), entirely unlikely proportions given that primary feathers actually scale negatively to wingspan (in other words, big birds actually have proportionally small flight feathers - Kspeka 2014). 7-8 m wingspans are thus extremely unlikely for Argentavis skeleton and lower values - around 6 m - are more realistic total wingspans.

The wing bones of various large birds, as illustrated by Campbell and Tonni (1983). That's the incomplete Argentavis humerus at top, a critical bone for estimating its wingspan. Alas, it's not 100% complete and we have to estimate how much was missing, especially from the proximal region.
And this brings us to our second point: although 6 m has been the generally accepted wingspan estimate in teratorn studies, it might actually be the upper bound for Argentavis size, not an average or middling value. Kspeka (2014) modelled Argentavis wingspans using several different means of predicting feather length and found 6.07 m as his top value, with all other equations suggesting wing spreads of 5.09-5.7 m (Kspeka 2014). If accurate, these predictions suggest Argentavis might have been more likely to hit wingspans of 5-5.5 m than 6 m. This definitely takes Argentavis out of the running for having the largest wingspan of any bird. Wingspan estimates of big Pelagornis are 6-7 m and, in being based on much more complete material, we can be confident that we aren't overestimating their proportions (Mayr and Rubilar-Rogers 2010; Ksepka 2014).

The actual winner of the Grand Cenozoic Wingspan-off, Pelagornis (species shown here is P. chilensis, other species may have been a little larger). Of course, giant pterosaurs look at this competition to reach 6-7 m wingspans with rolled eyes and a bemused smile.
These revisions set our 70-80 kg Argentavis mass estimates in a new and interesting light. The mass of Argentavis was calculated using measurements of the hindlimb (specifically, the circumference of the tibiotarsus) which correlate well with total mass in living birds (Campbell and Tonni 1983). 70-80 kg sounds tenable for a 7-8 m span bird, but is very heavy for a 5-6 m one, especially if it’s meant to be a soaring species. According to my own mass/wingspan regressions*, 25-40 kg is a more likely mass for a bird this size. Might this suggest that Argentavis was either a heavyset bird with proportionally small wings (and maybe more swan-like than raptor-like in flight?), or might its legs be sending a skewed signal on account of being proportionally robust? There may be something to the latter idea (see below) but, in any case, this conflicting data is something we could investigate using other means of predicting mass, ideally those which estimate body volume instead of relying on scaling equations. Regressing mass from linear measurements can be useful but is also easily thrown when fossil animals are outside the size range or body shapes of living animals. There are already Argentavis skeletal reconstructions out there (e.g. Paul 2002, Chatterjee et al. 2007) waiting for this approach, and the results would shed light on which of those mass values (if either) is more likely.

*Based on 90 bird species with values taken from various literature.

2) Teratorns probably weren't giant Neogene vultures

This conflicting mass data has bearing on the other widely known ‘fact’ of teratornithid palaeobiology: that they were vulture-like scavengers. This idea is hugely influential in teratorn palaeoart where they are unwaveringly restored with condor- or vulture-like integuments and colours. It may be surprising to learn that, while vulture-like lifestyles are not without support (e.g. Palmqvist and Vizcaíno 2003; Fox-Dobbs et al. 2006), since the 1980s most studies of teratornithid functional morphology have suggested they were actually poorly suited to scavenging, and were instead active predators. Much of this research focuses on the best-known teratorn, Teratornis, but there's little reason to think that what's said for this taxon does not apply to the group as a whole.

It’s true that, at first glance, teratornithids seem like ideal scavengers. After all, flight studies and their phylogenetic affinities suggest that teratornithids were exceptional soarers, using updrafts to travel vast distances across American mountain ranges and open plains (e.g. Campbell and Tonni 1983; Vizcaíno and Fariña 1999; Chatterjee et al. 2007). Their upper jaws terminate in a hook that seems suited to ripping into carcasses and, as likely relatives of cathartids (and once considered relatives of storks), habitual scavenging would seem to be in their blood. The recovery of many Teratornis bones from the La Brea Tar Pits, to which they were presumably attracted by the promise of dead or dying animal flesh, is the cherry atop this particular palaeoecological cake.

Teratornithid skull material, so much as it is known, contrasts markedly with that of scavenging birds. The overall construction is more consistent with raptors that take live prey and, some details (the distended palate) are albatross-like, perhaps an adaption for prey restraint. From Campbell and Tonni (1981).
There are several compelling reasons to reject the scavenging hypothesis, however. To start with, Campbell and Tonni (1981, 1983) and Hertel (1995) noted numerous differences in skull structure between Teratornis and scavenging birds and linked these to foraging mechanics. Raptor skull shape is strongly influenced by dietary preferences (Hertel 1995) so the distinction between vulturine and teratornithid skulls is not to be shrugged off. Vulture skulls have low, narrow, largely inflexible and strongly hooked rostra which work essentially like meat hooks: they latch into chunks of flesh and pull them from carcasses using strong neck movements. They’re also mechanically weak against all but vertical forces, this probably reflecting the immobile nature of vulture foodstuffs and, for some species, limited options for lateral head motion when throngs of vultures feed at one carcass (Hertel 1995). Campbell and Tonni (1981) report that Teratornis, in contrast, has a highly flexible and broad skull with a deep, dorsoventrally parallel rostrum. Though possessing a well developed rostral hook, its size and association with a robust and straight jaw better matches raptorial grabbing aids than a vulturine 'meat hook', and thus seems ill-suited to tearing flesh (Hertel 1995). While scavenging is not precluded by this configuration, the bulky but loosely built teratorn skull does not match predictions of skull morphology for a habitual scavenger.

A better morphological match for teratorn skulls are birds which dine on living prey, such as large eagles and - more surprisingly - albatross (Campbell and Tonni 1981; Hertel 1995; Paul 2002). Like albatross, Teratornis has a low-slung palate which nestles neatly between the rami of the lower jaws when the mouth closes. This configuration grips prey by pinching it between the lateral surface of the palate and the inner margin of the mandible. Intriguingly, Hertel (1995) also found a maritime connection with Teratornis skulls, noting some skull proportions uniquely matching those of piscivorous raptors. Combined with the albatross-like jaw structure, we might wonder if aquatic prey was a routine part of teratorn diets (an idea also suggested by Paul 2002). I’m not fully convinced of this because the biometric signal of piscivorous raptor skulls is not strongly separated from those with less specialised diets (data in Hertel 1995), teratornithid skeletons lack features we’d expect of habitual waders or fishers and - perhaps most tellingly - Teratornis bone chemistry indicates a diet of terrestrial animals (Fox-Dobbs et al. 2006). These skull features are nevertheless evidence of teratorns being live-prey carnivores, not scavengers. Their strongly kinetic skulls - which included a loosely jointed mandible, and a jaw joint that expanded their gape 10% when the mouth is opened - implies a great ability to swallow prey whole at the expense of capabilities to tear it apart (Campbell and Tonni 1981). We might thus summarise their skull morphology as being suited to grabbing, holding and swallowing small animals.

The pelves of teratornithids weren't like those of other raptors, but more akin to those of birds which spend a lot of time walking around. From Campbell and Tonni (1983).
Working out what sort of prey teratorns preferred is aided by examining their skeletons. We can immediately rule out the use of their feet in capturing and restraining prey, these lacking the long, robust talons and indicators of a powerful grip characteristic to many birds of prey (Campbell and Tonni 1983). Teratornithids also have pelves which differ markedly from raptors that use their legs in prey capture. Eagles, falcons and similarly adapted birds have strongly bent posterior pelvic regions which optimise the orientation of their hindlimb musculature for powerful leg action. Teratornithids, in contrast, have relatively straight pelves that recall those of storks and other birds adapted for walking more than those of their raptorial cousins. Combined with their non-raptorial feet, we can probably rule out teratornithids gripping and carrying prey with their legs (Campbell and Tonni 1983), but can assume that they'd be much more comfortable striding around the ground than most other raptors.

Put together, these hindlimb features, the functional signature of their skulls and terrestrially-derived bone chemistry has seen many authors agree that teratornithids must have been caracara-like ground predators of smallish prey (e.g. Campbell and Tonni 1981, 1983; Vizcaíno and Fariña 1999; Paul 2002; Chatterjee et al. 2007). Their stork-like pelves would have facilitated more efficient walking than those of other raptors and, without large claws to imbue their locomotion, their strong feet and long legs would be ideal for sustained bouts of terrestrial activity. This ecology might play into their mismatched leg and wingspan proportions because strong legs have clear advantages for terrestrially hunting birds. Perhaps teratornithids used their legs for occasional powerful ground activity, such as stamping or standing on prey (suggested by Campbell and Tonni 1981), providing bursts of speed or digging for hiding animals? Strong legs could have also facilitated rapid landing if prey was spotted from the air, or allowed for explosive launches to avoid danger. Teratornithids may have been large, but some species lived alongside even larger predatory mammals. Their leg proportions were not suited to fast running (Campbell and Tonni 1983) and rapid escape to the air was surely necessary on occasion. Around 80-90% of avian launch power stems from their hindlimbs so, if teratornithids wanted to get airborne rapidly, having substantial, strain-resistant leg bones would be a good start. I'm curious to know what the launch prospects of Argentavis are if we factor extremely robust hindlimbs at the lower body masses proposed above: could these birds perhaps launch from a standing start?

My take on Teratornis merriami as we probably need to start picturing it: a ground-stalking hunter of small prey, such as brush rabbits (seen half-eaten on the right of the image). Teratornis is deliberately reconstructed to look more 'predatory' than vulturine here, for reasons made clear in this post. A mew gull and turkey vulture are included as a nod to the rich avian fauna that once lived alongside teratorns: it's odd to think that species we have around today once lived alongside these very large and unusual birds.
With jaws suited to eating essentially any animal they could fit in their mouths, we might imagine teratornithids as stalking across Neogene plains, water margins and mountains looking for all manner of small vertebrate prey - lizards, snakes, frogs, smaller mammals, ground birds and so on. Campbell and Tonni (1981) suggest that the 24 cm long Teratornis skull would put a 9 cm diameter limit on prey size, while the much larger Argentavis - with an estimated skull length of up to 55 cm - could have swallowed 15 cm wide prey. That means hare-sized animals, including small sloths, armadillos, and the notoungulate Paedotherium borrelloi, could have been regularly going down the throat tubes of Argentavis. Sounds like some fun concepts for palaeoart to me.

So there we have it: teratornithids, household names for many of us interested in palaeontology, may have been both smaller and ecologically very different to how we've mostly imagined them. All this said, in researching this piece I was struck by how much of our work on teratornithid size and ecology is now decades old. This doesn’t invalidate the points outlined here, but there's probably scope for bringing modern techniques to teratorn studies, both to pin down their lifestyles further as well as to explore that interesting mass/wingspan issue. Teratornithids seem like pretty awesome birds, so hopefully modern insights into their anatomy and lifestyles won’t be long coming.

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  • Campbell Jr, K. E., & Tonni, E. P. (1981). Preliminary observations on the paleobiology and evolution of teratorns (Aves: Teratornithidae). Journal of Vertebrate Paleontology, 1(3-4), 265-272.
  • Campbell Jr, K. E., & Tonni, E. P. (1983). Size and locomotion in teratorns (Aves: Teratornithidae). The Auk, 100(2), 390-403.
  • Chatterjee, S., Templin, R. J., Campbell, K. E. (2007). The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina. Proceedings of the National Academy of Sciences, 104(30), 12398-12403.
  • Fox-Dobbs, K., Stidham, T. A., Bowen, G. J., Emslie, S. D., & Koch, P. L. (2006). Dietary controls on extinction versus survival among avian megafauna in the late Pleistocene. Geology, 34(8), 685-688.
  • Hertel, F. (1995). Ecomorphological indicators of feeding behavior in recent and fossil raptors. The Auk, 112(4), 890-903.
  • Ksepka, D. T. (2014). Flight performance of the largest volant bird. Proceedings of the National Academy of Sciences, 111(29), 10624-10629.
  • Mayr, G. (2009). Paleogene fossil birds. Springer Science & Business Media.
  • Mayr, G., & Rubilar-Rogers, D. (2010). Osteology of a new giant bony-toothed bird from the Miocene of Chile, with a revision of the taxonomy of Neogene Pelagornithidae. Journal of Vertebrate Paleontology, 30(5), 1313-1330.
  • Palmqvist, P., & Vizcaíno, S. F. (2003). Ecological and reproductive constraints of body size in the gigantic Argentavis magnificens (Aves, Teratornithidae) from the Miocene of Argentina. Ameghiniana, 40(3), 379-385.
  • Paul, G. S. (2002). Dinosaurs of the air: the evolution and loss of flight in dinosaurs and birds. JHU Press.
  • Vizcaíno, S. F., & Fariña, R. A. (1999). On the flight capabilities and distribution of the giant Miocene bird Argentavis magnificens (Teratornithidae). Lethaia, 32(4), 271-278.

Thursday, 25 July 2019

The science of the Crystal Palace Dinosaurs, part 4: The mammals of the Tertiary Island

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 Dinosaurs charity - 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.


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.


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.


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...

That brings our palaeoartistic review of the Crystal Palace palaeoartworks to a close, kudos to anyone who's read the entire series. This was meant to be little more than a series of brief notes and it's ended up being a number of long articles. Having already been interested in the Crystal Palace sculptures before writing this, I must admit to having a true fascination with them now. Writing these pieces has revealed so many gaps in our understanding of their history and development, allowed me to appreciate just what a good artist Hawkins was, and driven home the fact that the Geological Court sculptures were really not an Owen-Hawkins collaboration, but almost a solo Hawkins project. The latter point is already well made by records of correspondence between Owen and those involved in the Crystal Palace project, but trying to 'reverse engineer' Hawkins' artwork further demonstrates the token involvement Owen must have had. In this light, Hawkins really needs to be discussed more widely as one of the all-time greats of palaeoart. Despite relatively little scientific assistance, he produced spectacular, realistic and charismatic takes on fossil animals at a time when our understanding of animal anatomy - both fossil and modern - was a fraction of what it is today. Yes, he got many things 'wrong' with respect to our modern understanding and he perhaps leaned on living animals more than we would nowadays, but to focus on this, and not his achievements in anatomical prediction, his knowledge of contemporary science and attention to anatomical detail, does him a disservice. We have to evaluate the Geological Court models in light of what was known at the time, and in this respect they are truly first rate. Far superior in science and art, in fact, to the vast majority of palaeontological sculptures exhibited today.

Furthermore, I feel more committed than ever to the fact that these models should, no, must be conserved for future generations. As globally unique monuments to Victorian science and culture, we should regard them with pride, reverence and admiration, and not allow them to deteriorate through neglect, underfunding and (sad to say) deliberate vandalism. The ongoing work by the Friends of Crystal Palace Dinosaurs is essential to this mission and I salute them for pushing the value of these sculptures against the odds, and for their successes so far. As I've said repeatedly throughout this series, if you share my interest and concern for Hawkins' Crystal Palace palaeoartworks then check out the FOCPD website you see how you can help: chip in some money to help conserve the models or provide some elbow grease to help maintain the Geological Court. If we let these models slide too far into disrepair there's no coming back for them: all their artistry, history and scientific significance will be gone for good. Please take interest and help out if you can.

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  • Anonymous. (1871). Crystal Palace: Guide to the Palace and Park. R.K. Burt, London.
  • Argot, C. (2008). Changing views in paleontology: the story of a giant (Megatherium, Xenarthra). In Mammalian Evolutionary Morphology (pp. 37-50). Springer, Dordrecht.
  • Bargo, M. S., Toledo, N., & Vizcaíno, S. F. (2006). Muzzle of South American Pleistocene ground sloths (Xenarthra, Tardigrada). Journal of Morphology, 267(2), 248-263.
  • Cuvier, G. (1827). Essay on the Theory of the Earth. W. Blackwood.
  • Dawson, G. (2016). Show me the bone: Reconstructing prehistoric monsters in nineteenth-century Britain and America. University of Chicago Press.
  • Doyle, P. (2008). A vision of ‘deep time’: the ‘Geological Illustrations’ of Crystal Palace Park, London. Geological Society, London, Special Publications, 300(1), 197-205.
  • Doyle, P., & Robinson, E. (1993). The Victorian ‘Geological Illustrations’ of Crystal Palace Park. Proceedings of the Geologists' Association, 104(3), 181-194.Hooker, J. J. (2007). Bipedal browsing adaptations of the unusual Late Eocene–earliest Oligocene tylopod Anoplotherium (Artiodactyla, Mammalia). Zoological Journal of the Linnean Society, 151, 609-659.
  • Geist, V. (1999). Deer of the World. Swan Hill Press, Shrewsbury.
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  • Lister, A. M. (1987). Megaceros or Megaloceros? The nomenclature of the giant deer. Quaternary Newsletter, 52, 14-16.
  • McCarthy, S., & Gilbert, M. (1994). The Crystal Palace dinosaurs: The story of the world's first prehistoric sculptures. Crystal Palace Foundation.
  • Woodward, A. S., & Moreno, F. P. (1899). On a Portion of Mammalian Skin, named Neomylodon listai, from a Cavern near Consuelo Cove, Last Hope Inlet, Patagonia. Proceedings of the Zoological Society of London, 67, 144-156.
  • Owen, R. (1842). Description of the Skeleton of an Extinct Gigantic Sloth: Mylodon Robustus, Owen, with Observations on the Osteology, Natural Affinities, and Probable Habits of the Megatherioid Quadrupeds. J. van Voorst.
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  • Owen, R. (1854). Geology and inhabitants of the ancient world (Vol. 8). Crystal Palace Library.
  • Owen, R. (1856). On the Affinities of the Stereognathus ooliticus (Charlesworth), a Mammal from the Oolitic Slate of Stonesfield. Quarterly Journal of the Geological Society, 13, 1-11.
  • Owen, R. (1857). Description of the Lower Jaw and Teeth of an Anoplotherioid quadruped (Dichobune ovina, Ow.) of the size of the Xiphodon gracilis, Cuv., from the Upper Eocene Marl, Isle of Wight. Quarterly Journal of the Geological Society, 13 254-260.
  • Phillips, S. (1854). Guide to the Crystal Palace and park. Crystal Palace Library.
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  • Rémy, J. A. (1992). Observations sur l'anatomie crânienne du genre Palaeotherium (Perissodactyla, Mammalia); mise en évidence d'un nouveau sous-genre, Franzenitherium. Palaeovertebrata.
  • Rudwick, M. J. (1992). Scenes from deep time: early pictorial representations of the prehistoric world. University of Chicago Press.
  • Rudwick, M. J. (1997). Fossil Bones and Geological Catastrophes. New Translations & Interpretations of the Primary Texts. University of Chicago Press.
  • Rudwick, M. J. (2005). Bursting the limits of time: the reconstruction of geohistory in the age of revolution. University of Chicago Press.
  • Wall, W. P. (1980). Cranial evidence for a proboscis in Cadurcodon and a review of snout structure in the family Amynodontidae (Perissodactyla, Rhinocerotoidea). Journal of Paleontology, 54, 968-977.

Sunday, 30 June 2019

Monsterising prehistory! The "how", "why" and "so what" of monstrous palaeoart

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 Palaeontology blog, 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 blog to 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!

Thursday, 30 May 2019

The science of the Crystal Palace Dinosaurs, part 3: Megalosaurus, Hylaeosaurus and Iguanodon

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 Dinosaurs charity 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 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.

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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?


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.


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.

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