Walking from water

The emergence of the first vertebrates from the seas and onto the land marked a key point in the history of life, but few fossils of the early tetrapods have been found from this period — often referred to as Romer's Gap. In 4 July Nature, Jennifer Clack at the University Museum of Zoology, Cambridge, UK, describes a near complete fossil amphibian that casts light on the limb development of these tetrapods (Nature 2002, 418:72-76).

Clack reclassified a fossil that had originally been misidentified as a rhizodont fish, discovered in 350-million-year (Myr) old deposits from Dumbarton, Scotland, and renamed it Pederpes finneyae — meaning 'rock crawler'. It has a five-digit pes (foot) and probably resembled a large skulled, rather ungainly crocodile. Features characteristic of fish e.g. grooves in the skull for lateral-line canals suggest that it lived at least partly in the water and almost certainly reproduced aquatically, similar to ...