Biology

Vertebral evolution and the diversification of squamate reptiles

Document Type

Article

Abstract

Taxonomic, morphological, and functional diversity are often discordant and independent components of diversity. A fundamental and largely unanswered question in evolutionary biology is why some clades diversify primarily in some of these components and not others. Dramatic variation in trunk vertebral numbers (14 to >300) among squamate reptiles coincides with different body shapes, and snake-like body shapes have evolved numerous times. However, whether increased evolutionary rates or numbers of vertebrae underlie body shape and taxonomic diversification is unknown. Using a supertree of squamates including 1375 species, and corresponding vertebral and body shape data, we show that increased rates of evolution in vertebral numbers have coincided with increased rates and disparity in body shape evolution, but not changes in rates of taxonomic diversification. We also show that the evolution of many vertebrae has not spurred or inhibited body shape or taxonomic diversification, suggesting that increased vertebral number is not a key innovation. Our findings demonstrate that lineage attributes such as the relaxation of constraints on vertebral number can facilitate the evolution of novel body shapes, but that different factors are responsible for body shape and taxonomic diversification. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution..

Publication Title

Evolution

Publication Date

4-1-2012

Volume

66

Issue

4

First Page

1044

Last Page

1058

ISSN

0014-3820

DOI

10.1111/j.1558-5646.2011.01491.x

Keywords

body shape, disparity, morphological diversity, rate of evolution, supertree, taxonomic diversity

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