The new research shows how the jaws of ancient crocodiles evolved to enable these animals to survive in vastly different environments, all whilst living alongside the dinosaurs 235 to 65 million years ago.
The research team examined variation in the morphology (shape) and biomechanics (function) of the lower jaws in over 100 ancient crocodiles, using a unique combination of numerical methods.
By analysing variation in the lower jaw, the researchers provide novel insights into how the feeding systems of ancient crocodiles evolved as the group recovered from the devastating end-Triassic extinction event and subsequently responded to the distribution of ecological resources, like habitat and foodstuff.
The research showed that, following the end-Triassic extinction, ancient crocodiles invaded the Jurassic seas and evolved jaws built primarily for hydrodynamic efficiency to capture agile prey, such as fish. However, only a small range of elongate lower jaw shapes were suitable in Jurassic marine environments.
The study has also revealed that variation peaked again in the Cretaceous, where ancient crocodiles evolved a great variety of lower jaw shapes, as they adapted to a diverse range of feeding ecologies and terrestrial environments, alongside the dinosaurs.
Surprisingly, the lower jaws of Cretaceous crocodiles did not have a great amount of biomechanical variation and, instead, the fossil record points towards novel adaptations in other areas of their anatomy, like armadillo-like body armour.
The research has been published in the journal Proceedings of the Royal Society B.
--ANI (Posted on 12-09-2013)