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Open Access Highly Accessed Research article

A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes

R Alexander Pyron1*, Frank T Burbrink23 and John J Wiens4

Author Affiliations

1 Department of Biological Sciences, The George Washington University, 2023 G St. NW, Washington, DC 20052, USA

2 Department of Biology, The Graduate School and University Center, The City University of New York, 365 5th Ave., New York, NY 10016, USA

3 Department of Biology, The College of Staten Island, The City University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA

4 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721-0088, USA

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BMC Evolutionary Biology 2013, 13:93  doi:10.1186/1471-2148-13-93

Published: 29 April 2013

Abstract

Background

The extant squamates (>9400 known species of lizards and snakes) are one of the most diverse and conspicuous radiations of terrestrial vertebrates, but no studies have attempted to reconstruct a phylogeny for the group with large-scale taxon sampling. Such an estimate is invaluable for comparative evolutionary studies, and to address their classification. Here, we present the first large-scale phylogenetic estimate for Squamata.

Results

The estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs of sequence data per species (average = 2497 bp) from 12 genes, including seven nuclear loci (BDNF, c-mos, NT3, PDC, R35, RAG-1, and RAG-2), and five mitochondrial genes (12S, 16S, cytochrome b, ND2, and ND4). The tree provides important confirmation for recent estimates of higher-level squamate phylogeny based on molecular data (but with more limited taxon sampling), estimates that are very different from previous morphology-based hypotheses. The tree also includes many relationships that differ from previous molecular estimates and many that differ from traditional taxonomy.

Conclusions

We present a new large-scale phylogeny of squamate reptiles that should be a valuable resource for future comparative studies. We also present a revised classification of squamates at the family and subfamily level to bring the taxonomy more in line with the new phylogenetic hypothesis. This classification includes new, resurrected, and modified subfamilies within gymnophthalmid and scincid lizards, and boid, colubrid, and lamprophiid snakes.

Keywords:
Amphisbaenia; Lacertilia; Likelihood support measures; Missing data; Serpentes; Squamata; Phylogenetics; Reptilia; Supermatrices; Systematics