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.
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.
Don't forget to follow me on Twitter. Follow @SteveVidovic
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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