Palaeontologia africana
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/13253
ISSN (print): 0078-8554
ISSN (electronic): 2410-4418
For queries regarding content of Palaeontologia africana collections please contact Jonah Choiniere by email : jonah.choiniere@wits.ac.za or Tel : 011 717 6684
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Item A new record of Procynosuchus delaharpeae (Therapsida: Cynodontia) from the Upper Permian Usili Formation, Tanzania(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Weide, D. Marie; Sidor, Christian A.; Angielczyk, Kenneth D.; Smith, Roger M.H.Procynosuchus, the best-known Permian cynodont, has a remarkably broad geographic range, with records stretching from southern Africa to Europe. Fossils of Procynosuchus are most common in the Upper Permian Dicynodon Assemblage Zone of South Africa, but also occur in coeval East African rocks. Currently, there is one documented occurrence from the Madumabisa Mudstone Formation of Zambia, and two specimens from the Usili (=Kawinga) Formation of Tanzania. The Tanzanian specimens include a poorly preserved, incomplete skull and a partial cranium originally attributed to Parathrinaxodon proops. The latter is now considered a subjective junior synonym of Procynosuchus delaharpeae. Here we report on a new specimen collected in 2007 near the base of Kingori Mountain in Tanzania. It preserves the postorbital region of the skull and the posterior portions of both lower jaws, each containing several intact teeth. A well-preserved postcanine tooth exhibits the dental hallmarks of Procynosuchus and permits unambiguous referral to this taxon. Recent fieldwork corroborates previous suggestions that the Usili tetrapod fauna includes representatives of the Tropidostoma, Cistecephalus and Dicynodon assemblage zones of South Africa. Moreover, the presence of several endemic Usili taxa (e.g. Katumbia, Kawingasaurus, Peltobatrachus), suggests that a straightforward correlation between the Usili tetrapod fauna and a particular assemblage zone from the Beaufort Group may not be possible.Item A new cynodont record from the Tropidostoma Assemblage Zone of the Beaufort Group: implications for the early evolution of cynodonts in South Africa(Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Botha-Brink, J.; Abdala, F.A new specimen of cynodont has been recovered from the lower Upper Permian levels of the Tropidostoma Assemblage Zone of the South African Karoo Basin. A series of characters, including the presence of an interpterygoid opening, triconodont postcanine teeth, which are circular in crown view, a probable lingual cingulum, and most significantly, the presence of a masseteric fossa high on the coronoid process, allows this specimen to be assigned to the Procynosuchidae. However, unlike most procynosuchids, precanine teeth are absent and the incisors are represented by four left and five right upper and probably, three lower teeth. Considering the small size of the new specimen from the Tropidostoma Assemblage Zone we identify it as a juvenile Procynosuchus delaharpeae, the only species currently recognized in the genus. The low number of incisors and absence of precanines in this specimen are interpreted as ontogenetic variation (i.e. juvenile characters). This discovery extends the biostratigraphic range of Procynosuchus, as it is now recorded in three assemblage zones, indicating that this taxon is the longest-lived cynodont in the Karoo Basin. The new specimen of Procynosuchus and the recently described Charassognathus gracilis, are the oldest global records of cynodonts, and indicate an earlier initial radiation of this lineage than was previously thought.