The tree of life is rich in examples of species that changed from living in water to a land-based existence. Occasionally, some species took the opposite direction. New insights, provided by a CT scan, into the anatomy of the inner ear of prehistoric reptiles, the thalattosuchians, revealed details about one of these evolutionary turning points.
During the Mesozoic era, these now-extinct crocodile relatives ventured into the ocean after a long semiaquatic phase. During this process, the skeleton of the thalattosuchians gradually adapted to the new pelagic habitat. In particular, the changes to the inner ear vestibular system of these reptiles enhanced their ability to swim.
Compared to whales, which adapted quickly to life in water without a prolonged semiaquatic stage, this is a strikingly different evolutionary path for the same transition. These new findings of an international research team were made possible by the use of a high-tech computed tomography (CT Scan) machine.