The evolution of herbivorous crocodilians

[Logo7]

A new study analyzing 146 fossilized teeth from 16 extinct crocodile relatives has determined that crocodilians evolved a vegetarian diet at least three times during their evolutionary history. The study determined this by counting the number of separate surface areas on each tooth, with carnivores having few separate surface areas in order to catch prey more easily and herbivores having several separate surface areas, enabling them to more easily chew on hardy plant parts. Some of the extinct crocodilian relatives had teeth with up to 20 separate surfaces, suggesting that they were designed to consume plant parts. Three separate groups were found to have these teeth, suggesting that tooth morphology changes for a vegetarian diet happened multiple times throughout the crocodilian evolutionary history. The study finds that Smilosuchus had some of the most complex teeth of the crocodile relatives studied, with them specifically resembling those of the herbivorous marine iguana, suggesting that it might have had a similar diet despite not being aquatic. The new study also determines that the reason for the disappearance of herbivorous crocodilians at the end of the Cretaceous, in addition to the later extinction of all fully terrestrial crocodilians, may have resulted from the disappearance of the plants that their teeth were specialized for or from the emergence of herbivorous mammals to fill their old niche. However, some modern crocodilians do still consume plant material, suggesting that there may be some remnants of their ancient herbivorous ancestors left within their genetic code. Here are some images of some of the 3D printed models of the teeth of some of the herbivorous crocodilians, a chart showing the diet of four crocodilian species that were examined in this study, and a link to the paper describing this study.





Paper (abstract only): https://www.cell.com/current-biology/fulltext/S0960-9822(19)30690-6

[Halichoeres]

Cool, I'm a big fan of these weirdo Mesozoic crocodile groups. Those reconstructions are beautiful.