Bird-like fossil footprints from the Late Triassic.

Full Abstract

The study of fossilized footprints and tracks of dinosaurs and other vertebrates has provided insight into the origin, evolution and extinction of several major groups and their behaviour; it has also been an important complement to their body fossil record. The known history of birds starts in the Late Jurassic epoch (around 150 Myr ago) with the record of Archaeopteryx, whereas the coelurosaurian ancestors of the birds date back to the Early Jurassic. The hind limbs of Late Triassic epoch theropods lack osteological evidence for an avian reversed hallux and also display other functional differences from birds. Previous references to suggested Late Triassic to Early Jurassic bird-like footprints have been reinterpreted as produced by non-avian dinosaurs having a high angle between digits II and IV and in all cases their avian affinities have been challenged. Here we describe well-preserved and abundant footprints with clearly avian characters from a Late Triassic redbed sequence of Argentina, at least 55 Myr before the first known skeletal record of birds. These footprints document the activities, in an environment interpreted as small ponds associated with ephemeral rivers, of an unknown group of Late Triassic theropods having some avian characters.

Author information

Author/s: Melchor, Ricardo N (RN); De Valais, Silvina (S); Genise, Jorge F (JF);

Affiliation: CONICET and Universidad Nacional de La Pampa, Av. Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina. melchor_r(-atsign-)cpsarg.com

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Nature (Nature), published in England. (Language: eng)

Reference: 2002-Jun; vol 417 (issue 6892) : pp 936-8

Dates: Created 2002/06/27; Completed 2002/07/19; Revised 2006/11/15;

PMID: 12087401, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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