Are crocodiles really monophyletic?--Evidence for subdivisions from sequence and morphological data

Mol Phylogenet Evol. 2006 Apr;39(1):16-32. doi: 10.1016/j.ympev.2006.01.012. Epub 2006 Feb 21.

Abstract

Recently, the phylogenetic placement of the African slender snouted crocodile, Crocodylus cataphractus, has come under scrutiny and herein we address this issue using molecular and morphological techniques. Although it is often recognized as being a "basal" form, morphological studies have traditionally placed C. cataphractus within the genus Crocodylus, while molecular studies have suggested that C. cataphractus is very distinct from other Crocodylus. To address the relationship of this species to its congeners we have sequenced portions of two nuclear genes (C-mos 302bp and ODC 294bp), and two mitochondrial genes (ND6-tRNA(glu)-cytB 347bp and control region 457bp). Analyses of these molecular datasets, both as individual gene sequences and as concatenated sequences, support the hypothesis that C. cataphractus is not a member of Crocodylus or Osteolaemus. Examination of 165 morphological characters supports and strengthens our resurrection of an historic genus, Mecistops (Gray 1844) for cataphractus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aldehyde Oxidoreductases / genetics
  • Alligators and Crocodiles / anatomy & histology
  • Alligators and Crocodiles / classification*
  • Alligators and Crocodiles / genetics
  • Animals
  • Cell Nucleus / genetics
  • Cytochromes b / genetics
  • DNA, Mitochondrial / genetics
  • Genes, mos / genetics
  • NADH Dehydrogenase / genetics
  • Ornithine Decarboxylase / genetics
  • Phylogeny*

Substances

  • DNA, Mitochondrial
  • Cytochromes b
  • Aldehyde Oxidoreductases
  • glutamyl tRNA reductase
  • NADH Dehydrogenase
  • Ornithine Decarboxylase