Article: Reappraisal of Geikia locusticeps (Therapsida: Dicynodontia) from the Upper Permian of Tanzania
The holotype and only known specimen of Geikia locusticeps (von Huene, 1942) from the Kawinga Formation (Tatarian) of Kingori, south-west Tanzania, is redescribed. It is compared to the type specimen of the Tanzanian geikiid Pelanomodon tuberosus von Huene, 1942. It is demonstrated that G. locusticeps is a juvenile specimen of P. tuberosus. Ontogenetic changes in the skull of this taxon are recorded. They mainly concern the degree of skull ornamentation, whereas the major osteological and proportional features remain remarkably constant. Pelanomodon tuberosus is referred to Geikia locusticeps as a junior subjective synonym. G. locusticeps is compared to Geikia elginensis and South African representatives of Pelanomodon. G. locusticeps is demonstrated to represent a valid species, one that is so far endemic to the Ruhuhu Basin of south-west Tanzania. The relevance of the orientation of the postorbital bone to Permian pristerodontian systematics is discussed, and a phylogenetic analysis and new diagnosis for the family Geikiidae are presented.