The Higher Level Relationships of the Extant Crocodylia

-The relationships of the three living groups of crocodilians (crocodylids, alligatorids and gavialids) are poorly understood. Recent molecular results favor a sister group relationship between the crocodylid genus Tomistoma and Gavialis, with this as the sister group to the crocodylids (Densmore, 1983). Buffetaut (1985) has reinterpreted some morphologic evidence as supportive of this viewpoint. This morphologic evidence is examined here using outgroup analysis; it fails to support this hypothesis. Few if any morphological features unambiguously support a Gavialis + crocodylid or Gavialis + Tomistoma relationship. Instead the classic pre-Darwinian phylogeny of Dumeril (1806) is corroborated by anatomical evidence. This phylogeny supports a monophyletic crocodylid + alligatorid clade as a monophyletic sister