The five metre-long holotype specimen of ‘Plesiosaurus’ megacephalus, from the Jurassic of Street-on-the-Fosse, Somerset, was one of several plesiosaurs once displayed in the Bristol Museum and Art Gallery. As one of the earliest plesiosaurs to evolve it is an important species for understanding the early history of the group. Sadly, the fossil skeleton was destroyed along with many other important specimens when the museum was struck by a bomb during the Second World War. This destroyed fossil material is sometimes referred to today as the ‘ghost collection’.
Thankfully, all was not lost. Moulds had been taken from some of the fossils before the war, and in the case of ‘Plesiosaurus’ megacephalus, multiple casts of its skull and forelimb were produced prior to its destruction. These were deposited in the collections of several museums, including the British Geological Survey (BGS), Keyworth; Natural History Museum, London; and Trinity College, Dublin.
The casts provide a valuable resource that I was able to use to describe ‘Plesiosaurus’ megacephalus in an article published this year in the open access journal Palaeontologia Electronica (18.1.20A p.1-19). The study focused on the casts held in the BGS, but was also facilitated by The Bristol Museum and Art Gallery who provided historical photographs of the ‘ghost collection’ from their archives. The photo (above) shows how the entire fossil skeleton appeared before it was destroyed. The BGS also produced three-dimensional digital laser scans of the casts as part of their JISC-funded ‘GB3D fossil types online’ project. The resulting virtual models are free to view or download (here) and can be rotated on screen or 3D-printed.
The skeleton of ‘Plesiosaurus’ megacephalus is distinct enough from all other plesiosaurs, including Rhomaleosaurus and Eurycleidus, to warrant a new genus name. I called it Atychodracon, meaning ’Unfortunate Dragon’, in reference to the unfortunate destruction of the original fossil material. This project also demonstrates that casts of fossils, and 3D laser scans, can provide valuable data for palaeontologists – they can be described, measured, and coded into analyses. When original fossil material has been lost, damaged or destroyed, the scientific value of casts increases even further. This study is the first publication to make use of the publicly available repository of 3D laser scans provided by the BGS. The Bristol Museum and Art Gallery is now investigating the possibility of using physical representations of their ‘ghost collection’ in future exhibitions, to bring long lost fossils such as Atychodracon ‘back to life’.
Find out more by checking out the article at Palaeontologia Electronica.
Many readers will be familiar with the giant plesiosaur on display in the marine reptiles gallery of the Natural History Museum, London. This is a cast of the 7 metre long holotype of Rhomaleosaurus cramptoni, the original of which is housed in the National Museum of Ireland (Natural History) and formed the basis for my PhD thesis back in (time flies!) 2007. However, The Natural History Museum, London, also has its very own massive (also ~7 m long) and quite real Rhomaleosaurus type specimen to rival the ‘Dublin Pliosaur’ in size. NHMUK PV R4853, the mighty Rhomaleosaurus thorntoni, is from the Toarcian (Lower Jurassic) of Northamptonshire. It was donated to the museum prior to 1922 but has never been described and figured in its entirety before.
My newest paper, co-authored with Roger Benson (Smith & Benson 2014), provides a detailed description and photographic atlas of the entire skeleton of Rhomaleosaurus thorntoni, and it was published by the Palaeontographical Society just in time for me to distribute copies to colleagues at the SVP annual meeting in Berlin last November (2014). Few monographs of this kind, i.e. a comprehensive treatments of a single taxon, exist for plesiosaurians, especially up-to-date ones, so the paper should prove useful. The monograph includes 35 photographic plates depicting, essentially, every bone in the skeleton from multiple angles. We describe the skeleton in detail and figure the more complicated elements as interpretive illustrations. It’s just a bigger than average descriptive paper, really, but one that has been many years in the making (even more than it usually takes!). I’ve been waiting for the published monograph to be listed on the Palaeontographical Society publications page prior to posting this article, but since it is not yet forthcoming I decided to post this anyway. I’ll update this blog entry with a link to the volume once it is listed. [Edit – here is the link]:The entire manuscript, including the photographs and figures, is completely new: this is not a rehash of my PhD thesis on Rhomaleosaurus. The skeletal reconstruction is brand new as well and I hope that it comes to replace my previous reconstruction of Rhomaleosaurus in time, which I was never completely satisfied with (figured in Smith , Smith & Dyke , and Smith ). It is important to highlight that the new reconstruction represents R. thorntoni specifically, which we demonstrate is a distinct species, whereas the previous reconstruction represented Rhomaleosaurus sp. using R. cramptoni where possible and R. thorntoni as a proxy where not. As such, the original reconstruction was a mishmash of two different species, with related scaling errors. Most of the differences apparent between the new and old reconstructions are, however, due to stylistic improvements and a greater attention to detail, rather than genuine anatomical differences between R. cramptoni and R. thorntoni. The lateral view, especially, had some perspective issues with the ribs and limbs, which are corrected in the new reconstruction. There is still some margin for error in the proportions of the tail and neck in the new reconstruction because these are incomplete in the holotype (and only known specimen) of R. thorntoni, but I’m much more satisfied with it.
There is some doubt over the systematic position of rhomaleosaurids. They are traditionally regarded as pliosaurs, but they might not really be included within that clade, so for this reason we refrained from referring Rhomaleosaurus to Pliosauroidea in the title. We don’t include a cladistic analysis in our monograph to investigate this question, but we do summarise all previous ones and identify areas of relationship consensus within the clade Rhomaleosauridae. More cladistic work is required to confirm whether rhomaleosaurids are an early plesiosaurian offshoot, or pliosaurs proper.So, where’s the PDF? Sadly, there isn’t one, and this has been discussed and debated in some detail over at SV-POW (here). I say ‘there isn’t one’, but what I really mean is that distribution of the PDF is forbidden, since a beautiful PDF does exist (I was annotating it in the final proof stages). I was hopeful that permission would be granted for me to share the final PDF along with the hard copies provided for authors to distribute, but it was not to be. Of course, I’m disappointed about the barrier this puts between my research and potential readers, and I’m concerned about the impact this might have on it being cited. However, the hard copy is a quality publication, which can be thought of as more of a book than a paper. Those individuals that require it for research purposes can always request one from me directly – I can’t make promises but drop me an email if you have a serious interest ([email protected]).
The Palaeontographical Society funded some of my visits to the Natural History Museum to see the fossil material and this influenced my decision to select the Monograph of the Palaeontographical Society as a publication venue for this work. Plus, the format suits such an exhaustive treatment. I’d like to thank the editor, Yves Candela, who made a significant contribution to the volume and coordinated the whole process.
Update: The monograph is now available for sale from the Pal Soc website here.
Smith, A. S. 2007. Anatomy and systematics of the Rhomaleosauridae (Sauropterygia: Plesiosauria). PhD thesis. University College Dublin, 278pp.
Smith, A.S. 2013. Morphology of the caudal vertebrae in Rhomaleosaurus zetlandicus and a review of the evidence for a tail fin in Plesiosauria. Paludicola 9 (3): 144–158.
Smith, A.S. and Dyke, G.J. 2008. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften, 95, 975-980.
Smith A.S. and Benson R.B.J. 2014. Osteology of Rhomaleosaurus thorntoni (Sauropterygia: Rhomaleosauridae) from the Lower Jurassic (Toarcian) of Northamptonshire, England. Monograph of the Palaeontographical Society, London: 168 (642), 1–40, pls 1–35.
It was once common knowledge that elasmosaurid plesiosaurs were bendy-necked beasts that swanned about near the surface, striking snake-like at slippery prey. It is now common knowledge that their necks were relatively rigid rod-like structures, the function of which remains something of a mystery. The truth, with regard to flexibility at least, is probably somewhere in between. The most recent study to provide estimates of flexibility in elasmosaurid necks gives ranges of motion in the region of 75–177° ventral, 87–155° dorsal, and 94–176° lateral, depending upon the thickness of cartilage present between adjacent vertebrae (Zammit et al. 2008). Visually, that looks something like this:
Elasmosaurids weren’t the completely stiff-necked creatures they’re sometimes made out to be — even a tiny amount of flexibility between vertebrae adds up when you have 70+ neck bones. But why did plesiosaurs have such a long neck in the first place? This is a difficult question to answer because 1. plesiosaurs are extinct and left behind no living descendants, and 2. there are no other extant aquatic long-necked organisms to provide analogues. To my knowledge (and correct me if I’m wrong) there are no long-necked fish, cetaceans, sea turtles, or any other long-necked organisms that spend their entire life underwater. At least not to the extent seen in plesiosaurs.
Elasmosaurids were weirdos, but they maintained this long-necked bauplan for 135 million years, so they were successful weirdos. The long neck also evolved independently in different plesiosaur lineages, some cryptoclidids have extremely long necks too, for example. This all indicates a strong selection pressure (or pressures) driving the evolution of the long neck in plesiosaurs, despite the great risk involved in exposing such a delicate part of the anatomy in an ocean filled with super-predators. The long neck was therefore obviously doing something(s) useful. However, we can only really guess what.
Here are the top possible functions for the long neck in elasmosaurids (I’ve ruled out those possibilities that would require flexibility greater than the estimates given above). Some of these ideas are reasonable and have been suggested before, while others are, ahem, unreasonable and quite ridiculous.
1. Stealth device. Fish are stupid. The long neck provided distance between the bulky body of the plesiosaur and the unsuspecting prey.
2. Getting into tight spots. Helpful for hunting in reefs, crevices, and kelp forests.
3. Sexual selection. The equivalent of a peacock’s tail – the longer and more brightly coloured the better.
4. Food storage. Hamsters have cheeks, plesiosaurs had necks. This might not be as ridiculous as it sounds. Leatherback turtles do something similar (despite their incredibly short necks) by having an extended oesophagus that wraps around the stomach. Their prey (usually jellyfish) is held in place in the oesophagus by backwards-pointing projections (papillae) while excess water is expelled. After temporary storage in the oesophagus the morsels are transported to the stomach. Perhaps elasmosaurids were jelly fish specialists too?
5. Bottom feeding. Hunting in soft sediment. I’m not sure how the long neck really helps here – maybe something akin to number 1?
6. A snorkel. An air supply for staying submerged for prolonged periods of time.
7. Surprise, mother flapper!
8. Energy saver. Moving costs energy, so a long neck might allow the plesiosaur to feed, slumped on the sea bed, hardly moving its body in the process.
9. Electrogenic organ. Plesiosaur necks housed electrocytes and so longer necks create higher voltage electric fields. For electrolocation (sensing prey), elecrofishing (stunning prey to be consumed at leisure), and/or electric defence (to protect from pliosaurs and mosasaurs). This hypothesis comes from here, and was raised to my attention by Darren Naish.
10. Wrench of death. Grab and twist – for pulling ammonites out of their shells. Originally suggested here – thanks again to Darren Naish for reminding me. Twist feeding has also been suggested for short necked pliosaurs, for which it makes morse sense to me.
Other suggestions are welcome! Edit – I’ve updated the list with some new suggestions and will add more soon based on the comments posted below…
Zammit, M., Daniels, C. B. and Kear, B. 2008. Elasmosaur (Reptilia: Sauropterygia) neck flexibility: Implications for feeding strategies. Comparative Biochemistry and Physiology, Part A, 150, 124–130.
“After 65 million years, the world’s greatest predator is back” – Max Hawthorne
“Oh blimey, we’re gonna die!” – an Englishman in Kronos Rising.
Note – this review contains minor spoilers.
Kronos Rising, the new novel by Max Hawthorne, is a man vs monster story of a giant pliosaur that terrorises a seaside Florida town. Author Max Hawthorne was kind enough to send me a copy of the novel to review and I promised to write about it here.
You might expect some resistance from me towards fanciful notions of pliosaur biology and physiology, but this isn’t the case, I’m always game for some science fiction, no matter how far fetched. Kronos Rising is no text book and it would be ridiculous to review it as such. However, a few comments on the science won’t hurt.
The eponymous pliosaur in Kronos Rising is a new species of Kronosaurus, dubbed Kronosaurus imperator. It isn’t specified what or where the type specimen is, or if the name is recognised by the ICZN, but that’s all by the by! The pliosaur – for there is only one – is a badass, just because, and I’m fine with that. She (it emerges that this pliosaur is female) surpasses bassassery into the realm of super-villainry, for she has a vast array of powers at her disposal. These include: bullet-proof armour, echolocation, infrared vision, a directional and “phenomenal sense of smell”, “sensitive eardrums” with an acute sense of hearing, “amplified power of healing”, “resistance to disease and bacteria”, a swimming speed in excess of 45 knots (52mph), and a bad temper to boot. When it isn’t killing it dreams of killing (no, really!). And, of course, at over 80 feet long (just over 24m), it is huge. Hawthorne goes out of his way to give his Kronosaurus imperator all the bells and whistles and it makes for a terrible foe!
Pliosaurs, of course, were not quite so terrible in reality, no real animal would have all of these adaptations. One sense – the sensitive underwater olfaction the pliosaur uses to track down its prey – is supported by evidence outlined in a Nature paper (Cruickshank et al. 1991), so Hawthorne has clearly done his research and consulted the literature. Most everything else is is speculation. Pliosaurs didn’t have armour or heavy-duty scales and were probably rather smooth like cetaceans are today, a more useful adaptation to an aquatic lifestyle. I’ve written before about the fossil evidence for huge pliosaurs, and the maximum size estimates level off at around 15m. Hawthorne’s speculative 24m long Kronosaurus is therefore an overestimate, but not outside the realms of possibility. We can roll with this – it’s science fiction.
The fascination with large size in the novel extends beyond the obvious immensity of the Kronosaurus itself, to massive boats and guns, strapping muscular men, and anglers out to seek the biggest catch. I know Max Hawthorne is a record breaking angler himself, so perhaps this is a fisherman thing? There are nautical terms aplenty throughout the novel and for that I appreciated the glossary at the back of the book. Still, I found the technical detail sometimes bogged down proceedings – I’m obviously a landlubber.
The novel contains several surprise twists but is generally conventional in both plot and character development. The love story, for example, is spelled out from the get go. The main male and female protagonists share troubled histories over which they can bond and this gives them both depth and motivation, but many of the characters in Kronos Rising come off as rather one dimensional – stereotypes of the genre I suppose. The dialogue, especially some of the innuendo-charged flirtation, made me cringe at times, and the phonetically spelled Jamaican accent didn’t work for me either – it was distracting.
The pliosaur, I noted, only seems to kill men. Perhaps this is some sort of karmic retribution for the monstrous misogynistic acts committed by men against women in this novel? Or, maybe it is simply because there are so few active female characters.
I couldn’t say with certainty where the creature came from in the first place. There are some flash-back scenes to the Late Cretaceous describing how a small population of prehistoric critters came to find themselves enclosed in a caldera during the explosive end to the Mesozoic Era. Incidentally, I should note that the heyday of the apex pliosaur was during the Middle-Late Jurassic and Early Cretaceous, and they became extinct before the end Cretaceous mass extinction event. Nevertheless, exactly how this location and its pliosaur inhabitant remained isolated (under water?) for 65 million years, and the details of the events leading to the release of its occupants into the present day ocean, are unclear. I guess this ambiguity was intentional but it is somewhat unsatisfying. With regard to plot twists I appreciated the tension generated by bringing the combustible mix of characters together in the climax.
In conclusion, this is a novel with obvious echoes of Jaws and Jurassic Park, and it is great to see pliosaurs get the attention they deserve, but I was never completely reeled in by Kronos Rising. There’s surely an audience out there for it, the glowing reviews of Kronos Rising on Amazon.com and elsewhere are testament to that, and indicate that I’m in the minority here! So, pick up a copy and find out for yourself!