While disagreeing on many other aspects of passerine systematics and evolution, most ornithologists of the 20th century agreed that the Passeriformes is one of the youngest avian orders.
Therefore, it was rather surprising when molecular data proposed that the evolutionary history of these birds dated back to the end of the Cretaceous .
Due to their ubiquity and enormous diversity, passerines have been the focus of many ecological, behavioral, anatomical and evolutionary studies.
This diverse order is believed to have originated before the break-up of Gondwana in the late Cretaceous.
Our analyses provide estimates of divergence times for the major groups of passerines, which can be used as secondary calibration points in future molecular studies.
Our analysis takes recent paleontological and geological findings into account and provides the best estimate of the passerine evolutionary time-scale currently available.
Basal crocodylomorphs such as Hesperosuchus and similar forms ("Sphenosuchia") were found as a paraphyletic grade leading to the clade Crocodyliformes.
Among avian-line archosaurs, Dinosauria is well supported.