Snakes lose their legs
Lizards stretch, burrow and shed their limbs, and the fossils catch them partway.
- When
- —
- Duration
- 10 million years
- Known to
- ± 10 million years
- Era
- Cretaceous, Mesozoic
Snakes emerge from within the lizards, and the Cretaceous preserves several forms with the transition incomplete. Najash from Argentina and the marine Pachyrhachis and Haasiophis from the Middle East retain functional hind limbs while already being recognisably snakes. Whether the ancestral snake was a burrower or a swimmer has been argued from these fossils for decades and remains open. Either way the body plan proves enormously successful: elongation plus loss of limbs plus a highly kinetic skull produces a predator that can swallow prey wider than its own head.