Dating the time of origin of major clades

A time-calibrated phylogeny of Archosauriformes indicates that the origin and initial diversification of Archosauria occurred during the early Triassic following the Permian-Triassic extinction.

Furthermore, all major basal archosaur lineages except Crocodylomorpha were established by the end of the Anisian.

Each terminal taxon is explicitly described and all specimens used in the analysis are clearly stated.

Additionally, each character is discussed in detail and nearly all of the character states are illustrated in either a drawing or highlighted on a specimen photograph.

This time-scale provides a temporal framework for further biogeographical, ecological, and co-evolutionary studies of the largest bird radiation, and adds to the growing support for a Cretaceous origin of Passeriformes.

Passeriformes (passerines) is the largest and most diverse avian order, comprising about 5,700 species and representing almost 60% of all living birds.

To view articles you must have the free Adobe Acrobat Reader. The version displays best on an i Pad, but may work on other devices that accept format.