Abstract

Based mainly on isolated tooth-bearing elements, the rhynchosaur remains from the South Devon coast (Fig. 1) were first noticed in the late 19th century and variously assigned to the genera Hyperodapedon Huxley or Rhynchosaurus Owen (see review in Benton, 1990). More complete specimens were recovered from the early 1980s onward (Spencer and Isaac, 1983; Benton, 1988, 1990, 1997; Benton et al., 1993, 1994; Hone and Benton, 2008), allowing the recognition of new taxonomic entities (Benton, 1990; Hone and Benton, 2008). The ‘Devon rhynchosaur’ (Benton, 1988) was initially considered as a new species of the genus Rhynchosaurus, R. spenceri Benton, 1990, with a partial skull and mandible (EXEMS 60/1985.292) designated as the holotype. More recently, both a partial post-cranium and a nearly complete skull (Benton et al., 1993; Hone and Benton, 2008) were assigned to that species, but following previous interpretations (Wilkinson and Benton, 1995; Langer and Schultz, 2000), Hone and Benton (2008) proposed its inclusion in a new genus, Fodonyx.
The aim of this paper is to assign the referred skull of Fodonyx spenceri described by Hone and Benton (2008) to a new genus and species. This is important for an accurate estimate of the rhynchosaur diversity of the Otter Sandstone Formation, which may include the most basal members of the two rhynchosaur lineages that further spread during Middle (‘stenaulorhynchines’) and Late (hyperodapedontines) Triassic times.