A new genus of rhynchosaur from the Middle Triassic of South-west England

Abstract

We present a description of new cranial and postcranial material representing a new genus of rhynchosaur (Diapsida, Archosauromorpha) from the Otter Sandstone Formation (Mid Triassic) of Devon, south-west England. The taxon had been named Rhynchosaurus spenceri Benton, 1990, but cladistic analysis of the clade, and one autapomorphy, show that it does not belong to Rhynchosaurus, and a new generic name is required. We propose the name Fodonyx for this genus. A cladistic analysis of the Rhynchosauria confirms the main discoveries of previous analyses, and that Fodonyx is sister group to the Hyperodapedontinae, the clade of Late Triassic rhynchosaurs. The new cladistic analysis, for which many more characters were coded for Fodonyx than before (a rise from 39 to 75 per cent), counter-intuitively produced less well-resolved results: the new codings of previously uncoded characters introduced conflict so that Fodonyx turns out to be less like the Late Triassic rhynchosaur clade than had been assumed before. © 2008 The Palaeontological Association.