Explosive Pleistocene diversification and hemispheric expansion of a “great speciator”

doi:10.1073/pnas.0809861105

Explosive Pleistocene diversification and hemispheric expansion of a “great speciator”

^aDepartment of Ecology and Evolutionary Biology, Biodiversity Research Center, and Natural History Museum, University of Kansas, Lawrence, KS 66047;
^bCenter for Biodiversity and Conservation and Department of Ornithology, American Museum of Natural History, New York, NY 10024;
^cDivision of Biological Sciences, University of Montana, Missoula, MT 59812;
^dBurke Museum of Natural History, University of Washington, Seattle, WA 98195; and
^eGeography Department, University of California, Los Angeles, CA 90095

Contributed by Jared Diamond, October 2, 2008 (sent for review July 10, 2008)

Abstract

Factors that influence speciation rates among groups of organisms are integral to deciphering macroevolutionary processes; however, they remain poorly understood. Here, we use molecular phylogenetic data and divergence time estimates to reconstruct the pattern and tempo of speciation within a widespread and homogeneous bird family (white-eyes, Zosteropidae) that contains an archetypal “great speciator.” Our analyses show that the majority of this species-rich family constitutes a clade that arose within the last 2 million years, yielding a per-lineage diversification rate among the highest reported for vertebrates (1.95–2.63 species per million years). However, unlike most rapid radiations reported to date, this burst of diversification was not limited in geographic scope, but instead spanned the entire Old World tropics, parts of temperate Asia, and numerous Atlantic, Pacific, and Indian Ocean archipelagos. The tempo and geographic breadth of this rapid radiation defy any single diversification paradigm, but implicate a prominent role for lineage-specific life-history traits (such as rapid evolutionary shifts in dispersal ability) that enabled white-eyes to respond rapidly and persistently to the geographic drivers of diversification.

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Footnotes

¹To whom correspondence may be addressed. E-mail: moyle{at}ku.edu, filardi{at}amnh.org, or jdiamond{at}geog.ucla.edu
Author contributions: R.G.M. and C.E.F. designed research; R.G.M., C.E.F., and C.E.S. performed research; R.G.M. analyzed data; and R.G.M., C.E.F., C.E.S., and J.D. wrote the paper.
The authors declare no conflict of interest.