The oldest evidence for limb regeneration has been found in fossils of a 300-million-year-old amphibian.

Credit: Carola Radke/MfN

Salamanders can regrow entire lost limbs. Usually, the regrowths are indistinguishable from those that they replace, but in some cases they have distinctive abnormalities such as fused or missing digits. Nadia Fröbisch and her colleagues at the Natural History Museum — Leibniz Institute for Evolution and Biodiversity Science in Berlin found similar abnormalities in fossils of Micromelerpeton credneri (pictured), a distant relative of modern amphibians.

This is the first fossil evidence for limb regeneration, and suggests that this ability originated in an ancient amphibian ancestor.

Proc. R. Soc. B 281, 20141550 (2014)