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Earth history’s imprint on evolution of modern birds (free pdf)

Ben Creisler

A new paper in open access:

Santiago Claramunt and Joel Cracraft  (2015)
A new time tree reveals Earth history’s imprint on the evolution of
modern birds.
Science Advances  1(11):  e1501005
DOI: 10.1126/sciadv.1501005

Determining the timing of diversification of modern birds has been
difficult. We combined DNA sequences of clock-like genes for most
avian families with 130 fossil birds to generate a new time tree for
Neornithes and investigated their biogeographic and diversification
dynamics. We found that the most recent common ancestor of modern
birds inhabited South America around 95 million years ago, but it was
not until the Cretaceous-Paleogene transition (66 million years ago)
that Neornithes began to diversify rapidly around the world. Birds
used two main dispersion routes: reaching the Old World through North
America, and reaching Australia and Zealandia through Antarctica. Net
diversification rates increased during periods of global cooling,
suggesting that fragmentation of tropical biomes stimulated
speciation. Thus, we found pervasive evidence that avian evolution has
been influenced by plate tectonics and environmental change, two basic
features of Earth’s dynamics.