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During the Jurassic, ca.180 million years ago, some crocs called thalattosuchians moved from land to water, becoming open-ocean swimmers. Just like whales did 100+ million years later.
Our team has a new study out today in @PNASNews, detailing this evolutionary transition.
Our team has a new study out today in @PNASNews, detailing this evolutionary transition.
We looked at the vestibular system of the inner ear, which senses balance and equilibrium. To do so, we CAT scanned dozens of fossil and modern crocs.
We found that the ears of land-living, semiaquatic, and open-ocean crocs are dramatically different. The fully aquatic (pelagic) species have thicker and stouter ears, probably because of density differences between land and water.
What's really cool is that ear shape changes over time, and across the family tree. The pelagic crocs evolved their unique ears after a long semiaquatic phase, different than whales, which evolved similar ears very quickly after entering the water.
Not only that, but the pelagic thalattosuchians--called metriorhynchids--evolved features of the skeleton that permitted them to swim (such as flippers) before changing their ears. Their sensory systems played catch up! (art by Dmitry Bogdanov)
The project was led by my fantastic PhD student @Julia__Schwab, who already is a leading expert on inner ear anatomy and evolution. Today I am one proud supervisor!!! Well done Julia--a PNAS paper for the first chapter of your PhD!
Our project, based at @GeosciencesEd, is funded by a generous grant from @LeverhulmeTrust, and includes @MarkYoung_84 in the key role as postdoctoral fellow. Mark is undoubtedly the world's expert on metriorhynchids, and has been an awesome co-supervisor for Julia.
We were joined by a superstar team of croc researchers from around the world, including @WitmerLab @JamesNeenan @jonahchoiniere @alanhturner @ExpeditionLive & many other colleagues who aren't on twitter, or whose handles I've forgotten (sorry!) :-) Thank you all!!
The paper can be read here: https://www.pnas.org/content/early/2020/04/15/2002146117
And here is a nice, clear, poetic writeup in the @NYTScience, written by @beckyferreira, with some great quotes from Julia, and kind commentary from @TheropodaBlog (thanks Andrea!). Pretty cool--a PNAS paper AND a NY Times profile for Julia!!
