Thursday, 20 September 2012

SVPCA Oxford- A review of some amazing palaeontology

It’s nearly been a week since the end of SVPCA Oxford. High time I made good with my promises and wrote the blog post. There was an unbelievable range of talks this year, working through them hierarchically, from jawless lower vertebrates (not Mesozoic) up to mammals, with the archosaur lineage stuffed in the middle. Not only was a large chunk of Vertebrata covered, but it was covered in a huge range of topics; phylogeny, function, morphology, functional morphology, trace-fossils and much more.
Perhaps one of the most pertinent papers for this blog was presented by Paul Barrett and co-authors (Barrett et al. 2012). The title was ‘The earliest known dinosaur?’ a bit of a punch line spoiler, but none the less an informative and entertaining talk ensued. To give a brief summary: the material, from the Triassic of Tanzania has been sat in drawers for years, but a renewed understanding of what it is that makes a dinosaur a dinosaur and a dinosauromorph a dinosauromorph allowed the research team to say that the specimen is definitely one or maybe the other. All joking aside, the specimen is fragmentary, comprising of a partial humerus and some hip and back vertebrae (sacral and dorsal), with some other referred material (originally assigned to separate genera and species) and from this the team established that this animal is either the earliest known dinosaur, or the closest known dinosauromorph to the Dinosauria. They also demonstrated that the bone growth of these specimens was rapid, much like that of dinosaurs, leaving me inclined to consider the material a dinosaur for now. This is great, because now we not only know what the earliest dinosaurs look like, but we can be fairly confident of where they come from and it closes up the ghost lineage on the cladogram. Even with a pinch of salt it certainly says a lot for the robustness of the current archosaur phylogenies, which are being corroborated by new fossil data.
Another impressive piece of work was by Falkingham and Gatesy (2012). The duo modelled track ways to establish the locomotion of small theropod dinosaurs. It sounds like a simple task that won’t return much information right? Well it’s not. They realised that the various morphologies of track ways available in the collections housed at the Beneski museum represented similar animals at different stages of penetration into a substrate. They found a stack which represented the same foot moving all the way through the substrate and tracked landmarks using a computer simulation. Lowe and behold a model of a foot emerged from this process. Not only did they have a foot that looked just like a small theropod’s, but they also had its range of motion, confirming that a small theropod dinosaur does indeed move like a modern bird/avian dinosaur.
In the world of pterosaur research, Dave Unwin presented a piece of research on the ontogenetic (growth) series of Darwinopterus (Unwin et al. 2012). Darwinopterus is a transitional pterosaur, between the derived pterodactyloids and basal forms. When originally described in 2010 (Lü et al. 2010) Darwinopterus was reported as being an example of modular evolution. Now, with the ontogenetic series studied by Unwin and company they have revealed one of the potential mechanisms by which the animals evolved. The suggested mechanism is heterochrony: the process of changing the developmental patterns of an animal, or removing them altogether. In Darwinopterus juveniles it was found that less caudal vertebrae were ossified and that they were shorter than in adults, therefore the short tails of early pterodactyloids such as Pterodactylus are interpreted as neotenous (retaining juvenile characters).
Frankly, there was too much great research to post on in one go, so I’ll briefly report on one more presentation and call it a day. Lorna Steel a curator at the NHM UK presented on behalf of Young and their co-authors (Young et al. 2012) on the metriorhynchid crocodiles Dakosaurus and Plesiosuchus. Metriorhynchids are fully marine crocodiles with tail flukes... pretty cool. Long story short they were huge and Plesiosuchus appears to have been a marine reptile predator, much like modern killer whales. I’m being supremely brief on this one, since it deserves its own post.
Also there is another crocodile paper to be reported on, but this will be reserved for when it is published.
So, all in all it was a great conference and we all have to be appreciative of what the organizers have done for us. They have kept a 60 year tradition going, allowing researchers to present cutting edge science on the clade Vertebrata.

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Barrett, P. Nesbitt, S. Werning, S. Sidor, C. & Charig, A. 2012. The earliest known dinosaur? Programme and Abstracts, SVPCA, 60th Annual Symposium on Vertebrate Palaeontology and Comparative Anatomy. 6-7.
Falkingham, P. & Gatesy, S. 2012. Using penetrative tracks to reconstruct limb kinematics of bipedal dinosaurs traversing semi-fluid substrates. Programme and Abstracts, SVPCA, 60th Annual Symposium on Vertebrate Palaeontology and Comparative Anatomy. 11-12.
Lü, J. Unwin, D.M. Jin, X. Liu, Y. & Ji, Q. 2009. Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull. Proceedings of the Royal Society, Biological Sciences, 277: 383-389.
Unwin, DM. Lü, J. Pu, C. Wu, Y. 2012. A short tale: Darwinopterus, ontogeny and pterosaur evolution. Programme and Abstracts, SVPCA, 60th Annual Symposium on Vertebrate Palaeontology and Comparative Anatomy. 24.
Young, M. Brusatte, S. de Andrade, M. Desojo, J. Beatty, B. Steel, L. Fernández, M. Sakamoto, M. Ruiz-Omeñaca, J. & Schoch, R. 2012. Comparative cranial osteology and feeding mechanics of two Late Jurassic macrophagous metriorhynchids from Europe. Programme and Abstracts, SVPCA, 60th Annual Symposium on Vertebrate Palaeontology and Comparative Anatomy. 22.

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