A new hypothesis of squamate evolutionary relationships from nuclear and mitochondrial DNA sequence data
Squamate reptiles serve as model systems for evolutionary studies of a variety of morphological and behavioral traits, and phylogeny is crucial to many generalizations derived from such studies. Specifically, the traditional dichotomy between Iguania and Scleroglossa has been correlated with major evolutionary shifts within Squamata. We present a molecular phylogenetic study of squamates using DNA sequence data from the nuclear genes RAG-1 and c-mos and the mitochondrial ND2 region, sampling all major clades and most major subclades. Monophyly of Iguania, Anguimorpha, and almost all currently recognized squamate families is strongly supported. However, monophyly is rejected for Scleroglossa, Varanoidea, and several other higher taxa, and Iguania is highly nested within Squamata. Limblessness evolved independently in snakes, dibamids, and amphisbaenians, suggesting widespread morphological convergence or parallelism in limbless, burrowing forms. Amphisbaenians are the sister group of lacertids, and snakes are grouped with iguanians and anguimorphs. Dibamids diverged early in squamate evolutionary history. Xantusiidae is the sister taxon of Cordylidae. Studies of functional tongue morphology and feeding mode have found significant differences between Scleroglossa and Iguania, and our finding of a nonmonophyletic Scleroglossa and a highly nested Iguania suggest that similar states evolved separately in Sphenodon and Iguania, and that jaw prehension is the ancestral feeding mode in squamates.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Biological and Environmental Research; National Science Foundation Grant DEB-9726064 (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 841917
- Report Number(s):
- LBNL-54655; R&D Project: LWEGLS; TRN: US200515%%793
- Journal Information:
- Systematic Biology, Vol. 53, Issue 5; Other Information: Submitted to Systematic Biology; Volume 53, No.5; Journal Publication Date: 10/2004; PBD: 19 May 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phylogenetic relationships among amphisbaenian reptiles based on complete mitochondrial genomic sequences
Evolution of eggshell structure in relation to nesting ecology in non-avian reptiles