Hostname: page-component-8448b6f56d-wq2xx Total loading time: 0 Render date: 2024-04-20T13:45:50.268Z Has data issue: false hasContentIssue false

Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida)

Published online by Cambridge University Press:  17 May 2011

Stephen L. Brusatte
Affiliation:
Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA Email: sbrusatte@amnh.org Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
Michael J. Benton
Affiliation:
School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK
Graeme T. Lloyd
Affiliation:
Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, UK
Marcello Ruta
Affiliation:
School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK
Steve C. Wang
Affiliation:
Department of Mathematics and Statistics, Swarthmore College, Swarthmore, PA 19081, USA

Abstract

The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic faunas, but were more abundant in the Late Triassic and pre-eminent globally by the Early Jurassic. The archosaur radiation was a drawn-out event and major components such as diversity and abundance were discordant from each other. Crurotarsans (crocodile-line archosaurs) were more disparate, diverse, and abundant than avemetatarsalians (bird-line archosaurs, including dinosaurs) during the Late Triassic, but these roles were reversed in the Early Jurassic. There is no strong evidence that dinosaurs outcompeted or gradually eclipsed crurotarsans during the Late Triassic. Instead, crurotarsan diversity decreased precipitously by the end-Triassic extinction, which helped usher in the age of dinosaurian dominance.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)