A new and unusual procolophonid parareptile from the Lower Triassic Katberg Formation of South Africa

Abstract

ABSTRACT A small skull collected from the base of the Katberg Formation of South Africa represents a new Early Triassic procolophonid parareptile. Phonodus dutoitorum, gen. et sp. nov., is diagnosed by a roughly straight ventral temporal margin, prefrontals that contact each other along the dorsal midline, presence of a large posterior maxillary tooth, an edentulous pterygoid, a reduced transverse flange of the pterygoid, and other autapomorphies. A cladistic analysis identifies P. dutoitorum as a basal member of the procolophonid clade Leptopleuroninae. The presence of large maxillary teeth, their positioning ventral to strongly developed antorbital buttresses, and the loss of the ventral temporal emargination are suggestive of a durophagous diet. Phonodus dutoitorum is recognized as the oldest known leptopleuronine. Optimization of geographic distributions onto procolophonid phylogeny indicates that the presence of P. dutoitorum in the Karoo Basin of South Africa is explained most parsimoniously as the result of migration from Laurasia. Phonodus dutoitorum is the fifth procolophonoid species to be described from the Induan of the Karoo Basin, providing further support for the hypothesis that procolophonoid evolution was not greatly perturbed by the end-Permian extinction event.