SVP Annual Meeting 2010 - Part 2

So, yesterday was a big day for crurotarsans (although Crocodylomrpha was most widely represented) and the Romer Prize Session on Monday also included some very good croc talks.

Romer Prize Session:
For those of you who are not as familiar with SVP "the Alfred Sherwood Romer Prize recognizes an outstanding scientific contribution in vertebrate paleontology by a predoctoral student." The Romer Prize Session is a series of talks held during the meeting in which one speaker is then chosen as the winner of the Aldred Sherwood Romer Prize and the winner is announced at the awards ceremony on the last night of the meeting. Below, I list the talks from the session that were pertinent to the clade Crurotarsi, as well as any notes I had on the talk.

• "Tooth pressure, niche occupation and the evolution of the cranial ecomorphology of crocodylians." by P. Gignac.
• discussed how body size is mostly able to explain bite force and that tooth pressure in crocodylians often exceeds the shear stress limit of bone
• produced a model that was able to predict individual bite force, giving insight into individual variation
• "Seasonality as a potential source of variation in Alligator cranial evolution." by R. Sadleir
• This was an excellent talk (partially because epigenetics were discussed) focusing on phenotypic plasticity as affected by seasonality (and aseasonality)
• studied ranch animals and wild animals from the same breeding population (also was very good at taking into account many other variable that may have also been sources of phenotypic plasticity)
• showed how seasonal vs aseasonal environments induced large amounts of phenotypic plasticity that may explain some instances of speciation within Alligator
• "Evolution of salt-water tolerance in the Crocodylia and related crocodylomorphs: new insights from stable isotopes." by P. Wheatley 
• distribution and phylogeny suggests salt-water tolerance as an ancestral trait in crocodylomorphs, evolving at least as far back as Dyrosauridae + Crocodylia and becoming secondarily lost in alligators and gharials
• since it is quite reasonable to assume that thalattosuchians were salt-water tolerant, they can be used as a geochemical proxy for salt-water tolerance in fossils (using carbon isotopes to show access to marine food sources and oxygen isotopes to show marine vs. freshwater "drinking")
• Evidence suggests that dyrosaurids were salt-water tolerant and possibly even pelagic. If they were indeed pelagic, why did dyrosaurids survive the K-T extinction when so many other large taxa living in the same environment went extinct? Perhaps the juveniles were living in a freshwater environment (in fact, an audience member confirmed the presence of juvenile dyrosaurids in freshwater sedimentary environments).

If you ask me, I think both Sadleir and Wheatly are good candidates for the Romer Prize. Other talks of note were Jen Olori's talk on "Developmental featured of Microsaurs (Lepospondyli)", J. Scannella's talk on "Triceratops: A Model Organism for Deciphering Dinosaur Heterochrony" (this was a phenomenal talk, but may not get the Romer Prize because he did not focus enough on his own personal role in the research), and M. Spaulding's talk on "Phylogeny of the Carnivoramorpha". Stay tuned to hear about the winner of the prize.

Monday afternoon also yielded a few more talks on Crurotarsans, including one on a phytosaur, Pseudopalatus (although it was a somewhat poor talk), and a fantastic talk on the phylogenetic position of Thalattosuchia.

• "Fossil crocodyliforms and turtles from the Early Cretaceous of Northeastern Mali" by Hill et al
• "The endocranium, inner ear, and pneumatic structure of the Upper Triassic phytosaur Pseudopalatus pristinus" by Smith et al
• "Thy phylogenetic position of Thalattosuchia (Crocodylomorpha) and the importance of outgroup choice" by Eric Wilberg
• "Opportunism, acoustics and mass: exaptation and patterns of middle-ear expansion in Archosauria" by Dave Dufeau and Larry Witmer

More on Tuesday talks and the auction later.