Fossil footprints could push back origin of first four-limbed animals

摘要

Fossilized footprints found in an abandoned quarry in Poland hint that four-limbed creatures called tetrapods evolved much earlier and in a radically different environment than previously thought.rnThe footprints - many individual impressions, as well as some arranged in sets called trackways - are preserved in 395-million-year-old rocks in the HolyrnCross Mountains of southeastern Poland, paleontologist Per E. Ahlberg and colleagues report in the Jan. 7 Nature. That age substantially predates previous estimates for when animals left the sea to live on land.