Editor's Summary

7 January 2010

Four feet in the past: trackways pre-date earliest body fossils


The discovery of fossil trackways made by four-legged land vertebrates (tetrapods) almost 400 million years ago will cause a significant reappraisal of our understanding of tetrapod origins. The finds, reported by Per Ahlberg and colleagues, come from Zachelmie Quarry in the Holy Cross Mountains of Poland. Some of the tracks are so well preserved as to permit detailed examination of the foot morphology, which resembles that of the early, primitive tetrapod Ichthyostega. But it is their age that makes these tracks so special: 18 million years older than the earliest known tetrapod body fossils, and 10 million years older than the oldest elpistostegids — Tiktaalik , Panderichthys and their relatives, seen as transitional forms between fishes and tetrapods. The finds suggests that the elpistostegids that we know were late-surviving relics rather than direct transitional forms, and they highlight just how little we know of the earliest history of land vertebrates.

News and ViewsPalaeontology: Muddy tetrapod origins

The tracks left by organisms are among the most difficult of fossils to interpret. But just such evidence puts debate about the origins of four-limbed vertebrates (which include ourselves) on a changed footing.

Philippe Janvier & Gaël Clément

doi:10.1038/463040a

ArticleTetrapod trackways from the early Middle Devonian period of Poland

Grzegorz Niedźwiedzki, Piotr Szrek, Katarzyna Narkiewicz, Marek Narkiewicz & Per E. Ahlberg

doi:10.1038/nature08623