A team of paleontologists from the University of Michigan has examined the remains of an ancient ancestor of modern whales known as Aegicetus gehennae. He lived about 35 million years ago and almost never got out on land. And this is strange, because its skeleton has preserved rather large fragments of all four limbs that do not look like rudiments.
The remains were found back in 2007 in the Western Desert of Egypt. Presumably, it was a male, whose weight could reach 900 kg with a body length of up to 3, 7 m. The ancestors of whales were rather small land creatures that found it difficult to compete with other animals, which prompted them to go into the water. But the adaptation process stretched over millions of years - in particular, protocetid whales that lived 41-47 million years ago still had developed leg muscles, with which they swam.
In the species Aegicetus gehennae, by contrast, the limbs are small and, as a new study has shown, they no longer attach to the spine. That is, they are rudiments that exist separately from the main musculoskeletal system of the creature. Therefore, he could not row with them, and instead used a developing tail to move like a crocodile, in undulating movements. This is also indicated by a more powerful, thicker caudal section of the skeleton than that of its predecessors.