Nicholas
R. Longricha,1,
Bhart-Anjan
S. Bhullarb, and
Jacques
A. Gauthiera
Author
Affiliations
Edited
by David Jablonski, University of Chicago, Chicago, IL, and approved November
8, 2012 (received for review July 6, 2012)
Proceedings
of the National Academy of Sciences vol. 109 no. 52
Nicholas
R. Longrich, 21396–21401
Abstract
The
Cretaceous–Paleogene (K-Pg) boundary is marked by a major mass extinction, yet
this event is thought to have had little effect on the diversity of lizards and
snakes (Squamata). A revision of fossil squamates from the Maastrichtian and
Paleocene of North America shows that lizards and snakes suffered a devastating
mass extinction coinciding with the Chicxulub asteroid impact. Species-level
extinction was 83%, and the K-Pg event resulted in the elimination of many
lizard groups and a dramatic decrease in morphological disparity. Survival was
associated with small body size and perhaps large geographic range. The
recovery was prolonged; diversity did not approach Cretaceous levels until 10
My after the extinction, and resulted in a dramatic change in faunal
composition. The squamate fossil record shows that the end-Cretaceous mass
extinction was far more severe than previously believed, and underscores the
role played by mass extinctions in driving diversification.
1To
whom correspondence should be addressed.
E-mail: nicholas.longrich@yale.edu.
Author
contributions: N.R.L. designed research; N.R.L., B.-A.S.B., and J.A.G.
performed research; J.A.G. contributed new reagents/analytic tools; N.R.L.,
B.-A.S.B., and J.A.G. analyzed data; and N.R.L. wrote the paper.
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