Most developed legs in a snake

In 2006, a very special, new species of fossil snake, Najash rionegrina, was described from the Late Cretaceous Period (90 million years ago) of Patagonia, Argentina. Unlike all other fossil and modern-day snakes, it possessed not only a pair of robust hind limbs (certain living snakes, such as pythons, still harbour vestigeal versions) but also a sacral pelvic region. This would have enabled its hind limbs to articulate with its backbone, and it was probably a burrowing, terrestrial species.