Evidence from molecular systematics for decreased avian diversification in the Pleistocene Epoch

Robert M. Zink, Joseph B. Slowinski

Research output: Contribution to journalArticlepeer-review

117 Scopus citations


Pleistocene glaciations have been suggested as major events influencing speciation rates in vertebrates. Avian paleontological studies suggest that most extant species evolved in the Pleistocene Epoch and that species' durations decreased through the Pleistocene because of heightened speciation rates. Molecular systematic studies provide another data base for testing these predictions. In particular, rates of diversification can be determined from molecular phylogenetic trees. For example, an increasing rate of speciation (but constant extinction) requires shorter intervals between successive speciation events on a phylogenetic tree. Examination of the cumulative distribution of reconstructed speciation events in mtDNA phylogenies of 11 avian genera, however, reveals longer intervals between successive speciation events as the present time is approached, suggesting a decrease in net diversification rate through the Pleistocene Epoch. Thus, molecular systematic studies do not indicate a pulse of Pleistocene diversification in passerine birds but suggest, instead, that diversification rates were lower in the Pleistocene than for the preceding period. Documented habitat shifts likely led to the decreased rate of diversification, although from molecular evidence we cannot discern whether speciation rates decreased or extinction rates increased.

Original languageEnglish (US)
Pages (from-to)5832-5835
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number13
StatePublished - Jun 20 1995

Bibliographical note

Copyright 2007 Elsevier B.V., All rights reserved.


Dive into the research topics of 'Evidence from molecular systematics for decreased avian diversification in the Pleistocene Epoch'. Together they form a unique fingerprint.

Cite this