I promised myself back in 2007 that I’d cut down on the number of conferences I attend. There’s a problem with that: I’m pretty bad at keeping promises (at least, to myself). This year I’m attending a ridiculous four conferences, and I’ve just returned from the first of them (please remind me why I have no money, and no spare time). Entitled Sea Dragons of Avalon: the early radiations of the marine reptiles and recovery from the Triassic-Jurassic faunal crisis, with special reference to Street in Somerset and the wider British record, this Palaeontological Association (Pal Ass) seminar included a day of talks on the British marine record, as well as an additional day of field trips to the surrounds (for previous pre-emptive thoughts on the meeting, see here [May 2009], here [July 2009] and here [August 2009]). Yes, more ichthyosaurs and plesiosaurs than you can shake a proverbial stick at…
Any conference that discusses marine reptiles and faunal changes across any given boundary is a good thing, of course, but this meeting was actually much more: its raison d’être was to raise a glass to Arthur Cruickshank, a mentor and academic uncle to so many people who work in vertebrate palaeontology today [in the adajcent image, Arthur cuts a specially made cake. Yes, a cake with a historically significant plesiosaur on it: not every day you see that]. Arthur’s impact on the plesiosaur world is considerable, and – in a career spanning five decades – he’s also produced important contributions on archosaurs and synapsids. It seems high time that his role and influence be properly acknowledged. Because of constraints arising from Pal Ass’s charitable status, and (quite separately) from problems that can arise from mixed Festschrifts featuring disparate presentations, we very properly split the meeting into two financially independent elements. It consisted of the Pal Ass seminar proper (held nominally in Arthur’s honour, but with an entirely ‘logical’ programme), and a preceding informal Festschrift-style lunch party and more mixed set of papers. Well done to Mike A. Taylor, Leslie Noè, David Hill and Jeff Liston for the organisation, to Pal Ass for sponsorship… oh yes, and to me (though my role was very minor).
So, we had two days of talks. As usual, I’m not going to review or discuss all of them, but here are thoughts and recollections on, well, most of them.
Michael Benton reviewed his work on the changing fortunes of dicynodonts across the Permian Triassic Boundary (PTB). Much of this research will be familiar to you if you’ve read Fröbisch (2008) and Surkov & Benton (2008). Permian and Triassic dicynodonts occupied fairly different regions of morphospace, suggesting that they were quite different in terms of adaptations and so on, and that Permian-style dicyndonts failed to recover after the PTB. After the talk it only seemed appropriate to ask what Mike thought of the alleged Cretaceous dicynodont reported from Australia by Thulborn & Turner (2003). It seems that (just about) everyone is happy with its identification as a kannemeyeriiform (if I remember correctly, Tom Kemp stated that he’d examined it personally and was convinced by the identification): the question concerns its alleged Cretaceous date. Methinks we need isotope geochemistry or something to pin down its exact age, as has been suggested by others. While on the subject of anomodonts, the scansorial behaviour just proposed for Suminia by Fröbisch & Reisz (2009) was, needless to say, the talk of the town (figuratively) [adjacent Placerias reconstruction by Matt Celeskey of HMNH].
Adam Smith spoke about the ‘Dragons’ Dens’ (for those not in the UK, I should note that there’s a TV series called Dragons’ Den): that is, the storage history of the marine reptile collection now kept at the National Museum of Ireland’s Beggars Bush store. It’s a pretty sorry tale of woeful neglect and mismanagement really, as the many specimens have been moved four times and kept from access for decades. The crown jewel of the collection – the amazing, articulated, near-complete holotype of Rhomaleosaurus cramptoni (casts of which can be seen at various institutions) – was, during the early 1960s, broken into bits with a sledgehammer when it had to be moved in a hurry. A new project on this specimen was initiated in 2004 (Arthur provided advice), and here lies the origin of Adam’s Ph.D. work [Adam's world-famous R. cramptoni reconstruction shown here, borrowed from here on The Plesiosaur Directory].
Simon Carpenter discussed the many excellent finds he made in the Kimmeridge Clay at Westbury Quarry, Somerset. These included turtles, a spectacular pliosaur, and the holotype of the metriorhynchid Dakosaurus carpenteri. Unfortunately, the quarry is now closed, so no new discoveries! We also had talks from John Hudson on collecting trips in Scotland, and from Richard Edmonds on the Dorset Jurassic coast and on the problems of setting up a world-class collection centre in the area.
In view of Arthur’s involvement with the world of African archosaurs, it seemed fitting that we had at least some archosaur-themed content, and this was fulfilled in the form of David Norman’s talk on Heterodontosaurus. The many excellent illustrations demonstrate that the descriptive work on Heterodontosaurus is somewhere near completion [Heterodontosaurus cast shown here, from wikipedia]. Norman reviewed the discovery history of this unusual dinosaur, and also discussed its chewing behaviour. He argued that medial rotation of the mandibular rami was most likely, and hence that transverse grinding of some sort was occurring. Given that heterodontosaurids seem to be very basal within Ornithischia (Butler et al. 2008), it’s perhaps surprising that a fairly complicated jaw mechanism was already present, and one that was apparently distinct from the pleurokinesis and propaliny present in later, more derived ornithischians. If you’ve been following the dinosaur literature you might be interested, as I was, to know what Norman thinks of Holliday & Witmer’s (2009) contention that cranial kinesis was most likely absent in non-avian dinosaurs (this research was previously discussed here). Essentially, the response is that Holliday & Witmer didn’t discount the possibility of cranial kinesis altogether (they merely discounted certain kinds of kinesis), and that tooth wear data provides compelling support for pleurokinesis and other complex forms of kinesis. I think there’s a very interesting debate to be had here.
Mike A. Taylor and Jehane Melluish discussed the extremely interesting Thomas Hawkins, well known (in British vertebrate palaeontology) for acquiring good marine reptile fossils and for writing about them in (to our eyes) a bizarre style that combines scientific observation with a, shall we say, more colourful interpretation. As demonstrated by a number of feuds, disputes and legal cases, Hawkins was a bully and neighbour from hell (to use Mike’s term); he seems to have gotten some of his money by marrying at least one rich woman.
Richard Forrest (and an absent Mark Evans) reported the latest developments on the Collard plesiosaur [shown in adjacent pic, and in image below]. This is the small, damn-near-complete, fully articulated juvenile plesiosaur discovered on the beach at Bridgwater Bay, Somerset, by Nick Collard in 2003: quite probably the most extraordinary plesiosaur specimen ever found. It’s been CT-scanned and extensively x-rayed. It’s probably a rhomaleosaur, and possibly similar to the animal called Plesiosaurus macrocephalus: as discussed here, this species is not part of Plesiosaurus at all, and its affinities and taxonomy remain unresolved.
The flipper tips of the Collard specimen are gently curved posteriorly, suggesting that this was the case in life, and a gap between the coracoids and gastralia might provide support for the presence of a cartilaginous sternum. One peculiarity is that some bones, while clearly visible with the naked eye, don’t show up in the x-rays. Apparently, however, this is an artefact caused by pyrite content. The way the pelvis has collapsed indicates that it was originally quite deep… which of course brings us to the subject of plesiosaur body shape, a topic Tim Morris asked about in the comments a while ago. Plesiosaurs are a reasonably diverse bunch (well, within the constraints of a fairly conservative bauplan) and were not all alike. It seems that some (like cryptoclidids) were indeed fairly round in cross-section, while others (like some rhomaleosaurs) were far flatter, and wider than deep. I’m sure the many plesiosaurologists who visit Tet Zoo will provide additional thoughts in the comments. No pressure.
Academics in various disciplines are known to enjoy reconstructing their own ‘academic lineages’. In any given field of research, it’s often surprising how incestuous things have been, and on how influential one or a handful of individuals have been. Asking the question ‘Is there a Cambridge School of Palaeontology?’, Tom Kemp looked at Rex Parrington’s academic ‘descendants’. He tried to find synapomorphies and identified a clade. If you’re part of this clade, rest assured that you were mentioned – and perhaps even pictured – somewhere during this presentation.
Our first day finished with Ryosuke Motani’s public lecture ‘Street’s town symbol: the ichthyosaur two centuries since its discovery’. I suppose all I really need say is that Prof. Motani is clearly highly experienced at presenting a huge amount of technical information to a lay-audience in an understandable fashion. He covered his research on eyes, vision and deep-diving, the work on digit homology and flipper anatomy, and also showed how new work in China was ushering in a new phase in ichthyosaur research. It was a very impressive performance, and everyone seemed to enjoy it. On a technicality, one local lady told me that Street is not actually a town, but in fact a village (Europe’s largest village, apparently). However, this was most certainly not Ryosuke’s fault as we provided him with the title! [one of Chris Moore's ichthyosaurs shown in the adjacent image].
And that’s the end of part 1: more in the following article.
For previous articles relevant to some of the material discussed here see…
- SVPCA 2007: lepidosaurs, turtles, crocodilians, the plesiosaur research revolution continues
- A life secretly devoted to fish-lizards
- At the 56th SVPCA – hello Dublin!
- The skin of ichthyosaurs
Refs – –
Butler, R. J., Upchurch, P. & Norman, D. B. 2008. The phylogeny of the ornithischian dinosaurs. Journal of Systematic Palaeontology 6, 1-40.
Fröbisch, J. 2008. Global taxonomic diversity of anomodonts (Tetrapoda, Therapsida) and the terrestrial rock record across the Permian-Triassic Boundary. PLoS ONE 3(11): e3733. doi:10.1371/journal.pone.0003733
– . & Reisz, R. R. 2009. The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems. Proceedings of the Royal Society B doi: 10.1098/rspb.2009.0911
Holliday, C. M. & Witmer, L. M. 2008. Cranial kinesis in dinosaurs: intracranial joints, protractor muscles, and their significance for cranial evolution and function in diapsids. Journal of Vertebrate Paleontology 28, 1073-1088.
Surkov, M. V. & Benton, M. J. 2008. Head kinematics and feeding adaptations of the Permian and Triassic dicynodonts. Journal of Vertebrate Paleontology 28, 1120-1129.
Thulborn, T. & Turner, S. 2003. The last dicynodont: an Australian Cretaceous relict. Proceedings of the Royal Society of London B 270, 985-993.