Early Archosauromorphs: The Crocodile and Dinosaur Precursors

EZCURRA, MARTÍN D; JONES, A. S; GENTIL, ADRIEL R.; BUTLER, RICHARD J.

Encyclopedia of Geology, 2nd edition

Academic Press

Año: 2021; p. 175 - 185

Following the end-Permian mass extinction (c. 252 millionyears ago), archosaurian reptiles increased in abundance and diversity, comingto dominate Mesozoic terrestrial ecosystems from the Late Triassic onwards.Archosaurs (ruling reptiles) include dinosaurs and the flying pterosaurs, aswell as modern birds, crocodilians, and a variety of Mesozoic groups that liealong the crocodilian lineage (crocodile-line archosaurs). Archosaurs arediapsid reptiles that are part of a larger group known as Archosauromorpha anda less inclusive group known as Archosauriformes. Archosauriformes includesarchosaurs and their closest relatives, all of which share unique features ofthe skull such as an additional opening (the antorbital fenestra) between theeye socket and the nostril. Archosauromorpha is a broader grouping thatincludes archosauriforms and all species more closely related to them than tolepidosaurs (e.g., tuataras, lizards, snakes).