SVP Day 1

So after definitely not losing my passport, I managed to make it into one of the sessions for the first day at SVP, the Society for Vertebrate Palaeontology’s annual meeting over in Los Angeles.

The session was on the impacts of ontogeny, or growth and development on our understanding of dinosaur relationships and biology.

The only one I managed to catch was on the sauropod dinosaur, Lufengosaurus, where the researcher had taken thin sections through embryonic limb bones to track the change in shape through growth, or allometric variation. The authors were able to show that, due to the variation in the proportion of cavities and bone growth that these dinos grew at extremely fast rates, which is pretty cool, and may explain how these sauropods were able to get so big.

I skipped over to the mammal ecology session after this, and caught a neat talk on mammal teeth, and what they can tell us even when they’re only isolated or partial remains. Using 3D scans to get a digital version of teeth surfaces, which are pretty complex in mammals, you could see that it was possible to infer the complexity of the whole row of dental teeth, just using isolated remains.

Switching back to the ontogeny symposium, we had a look at the effects that it had on survivability over the Cretaceous/Paleogene boundary (the one where all non-avian dinos, and tonnes of other groups went kaput). This is known as selectivity, which are pressures acting upon certain features of animals or groups of animals, and leads to extinction. Ontogeny interacts with this by an animal or groups of animals occupying different ecologies as they grow. In dinosaurs, they have multiple ‘stages’ during ontogeny that have distinct ecologies, and it’s possible that by breaking this stage ‘chain’ at the K/Pg boundary, they were selectively more susceptible to extinction. Maybe.

Afternoon session! Of a tough three choices, I went for ornithischian dinosaurs – these are the other major clade of dinosaurs with saurischians, which includes the massive sauropods and theropods. Ornithischians are, for me, the unsung heroes of dinosaur palaeontology, as they often get side-lined in popular culture for either not being massive, or not being Tyrannosaurus rex. Really, despite being incredibly diverse.

The first couple of talks were awesome – ankylosaurs were the armoured, tail-clubbed and probably bad tempered group of ornithischians. A new phylogenetic tree showed some pretty cool things about their biogeographic patterns through time on a continental scale. You can map geography onto a tree, and combine it with palaeogeographic maps to look at how species dispersed through time and occupied new territories while evolving. The next talk was also on ankylosaurs, but more to do with the mystery of the origin of their tail clubs. New specimens have shown that the club is developed from modified distal caudal vertebrae, with the ‘knob’ appearing later on, or perhaps in tandem.

Ceratopsians, the cousins of ankylosaurs, have a complex history of cranial evolution, and environmental variations may have influenced the interaction between the skull and lower jaws in these species. Evolutionary rates may have also increased in the Late Cretaceous during the Late Cretaceous. Biogeographic analysis of these dudes, incorporating a new species from North America, it seems basal neoceratopsians originated in Asia, before dispersing into North America. This immigration may have happened in two ‘waves’, before North America and Asia split, but a relatively poor mid-Cretaceous fossil record obscures the precise timing of these events. The role of Europe in this interchange is currently complex, so you know what to do – go an hunt more fossils!

That’s about all I had the time and effort to cover! Myself and Dave Marshall managed to get a lot of cool content for Palaeocast, so check that out for more details too.