Mass survival of birds across the Cretaceous-Tertiary boundary: molecular evidence

The extent of terrestrial vertebrate extinctions at the end of the Cretaceous is poorly understood, and estimates have ranged from a mass extinction to limited extinctions of specific groups. Molecular and paleontological data demonstrate that modern bird orders started diverging in the Early Cretaceous; at least 22 avian lineages of modern birds cross the Cretaceous-Tertiary boundary. Data for several other terrestrial vertebrate groups indicate a similar pattern of survival and, taken together, favor incremental changes during a Cretaceous diversification of birds and mammals rather than an explosive radiation in the Early Tertiary.
The Cretaceous-Tertiary (K-T) boundary, 65 million years ago (Ma), was a key episode in recent vertebrate history, marking the end of the dinosaur era and the rise to predominance of [...]