Specialists disagree about the origin of modern snakes. Some think that its ancestor was a reptile that lost its legs and was styling its body to adapt to an aquatic habitat, characteristics that it maintained when it came out of the water. Others maintain that it was a lizard that in its passage to underground life dispensed with its legs to better move through tunnels and burrows.
Now, a new study claims that the “mother of all snakes” lived underground, and discards the marine reptile hypothesis. The authors of the work, published in Science Advances, are paleontologists Hongyu Yi (from the University of Edinburgh) and Mark Norell (from the American Museum of Natural History, in New York). For their research, they have used X-ray scanners with which they have created virtual 3D models of the inner ear of 44 species of modern reptiles and fossils of other extinct ones.
Later, they have compared these models with the inner ear of Dinilysia patagonica, a snake that lived about 90 million years ago and is related to the origin of these animals.
Snakes use the inner ear – a tiny bony structure located in their skull – for their hearing and balance. In the case of modern subterranean species and Dinilysia patagonica, this organ has a spherical shape, unlike that of aquatic snakes and those that thrive on the surface. This balloon shape would serve to more accurately detect low-frequency sounds , which would help subterranean snakes to detect the vibrations produced by their prey or predators when moving.
The analysis of extinct and current specimens has allowed scientists to deduce that Dinilysia patagonica , a reptile about 2 meters in length that is at the root of the evolutionary tree of modern snakes, was an underground and burrowing animal, and that it was also they were the snakes that gave rise to those we know today.
