Volume 56: 2023

Permanent URI for this collection

https://hdl.handle.net/10539/35651
Festschrift in Honour of Professor Bruce S Rubidge

Browse

Browsing Volume 56: 2023 by Author "Kammerer, Christian E."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Reappraisal of supposed ‘dinocephalian’ specimens expands burnetiamorph diversity in the Guadalupian Tapinocephalus Assemblage Zone of South Africa
    (2023-07) Day, Michael O.; Kammerer, Christian E.
    Burnetiids are a rare, yet seemingly species-rich family of therapsids in the rocks of the Karoo Basin of South Africa. Discoveries over the past 20 years have provided a greater understanding of the morphological variation within the group and have led to differing hypotheses of burnetiid phylogeny and that of their parent clade, Burnetiamorpha. One posits the existence within Burnetiidae of two subclades, Burnetiinae and Proburnetiinae, but this hypothesis invokes lengthy and thus problematic ghost lineages, particularly for proburnetiines. Herewereview and describe cranial material from the Capitanian Tapinocephalus Assemblage Zone that was previously referred to the dinocephalian therapsid Styracocephalus platyrhynchus, showing that it instead represents two new morphotypes of proburnetiine burnetiids. One of these, Nierkoppia brucei gen. et sp. nov., is diagnosed by the autapomorphic presence of a supraorbital boss ‘folded over’ the dorsal margin of the orbit, giving this structure a roughly ‘ear’ or ‘kidney’-shaped appearance; flattened, posteriorly directed squamosal horns; a median frontal boss taller than the supraorbital bosses, reaching itsmaximumheight anterior to them; and massive, rounded nuchal bosses borne on the postparietal and supraoccipital. The other specimen is left in open nomenclature due to incompleteness, but represents a heavily pachyostosed proburnetiine similar to Lende and Leucocephalus. The recovery of proburnetiines within theTapinocephalus Assemblage Zone shortens the ghost lineage of this clade and indicates that a diverse burnetiid fauna was present in the Guadalupian Karoo, comparable to that now known from Tanzania and Zambia.
  • Thumbnail Image
    Item
    Revision of the Scylacosauridae (Therapsida: Therocephalia)
    (2023-07) Kammerer, Christian E.
    The abundant, primarily middle Permian therocephalian family Scylacosauridae is comprehensively reviewed and revised. The 33 nominal scylacosaurid species from the Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa are reduced to seven: Alopecodon priscus, Alopecognathus angusticeps, Glanosuchus macrops, Maraisaurus parvus, Pardosuchus whaitsi, Pristerognathus polyodon, and Scylacosaurus sclateri. The scylacosaurid records from the earlier Eodicynodon Assemblage Zone (previously referred to Glanosuchus and Ictidosaurus) are recognized as a new taxon, Eutheriodon vandenheeveri. Scylacosaurid records from the later Endothiodon Assemblage Zone consist of two long-snouted taxa (the long-ranging species A. angusticeps and P. polyodon) and a short-snouted taxon (Hyorhynchus platyceps) possibly restricted to this zone. The revised identifications presented herein demonstrate that there was substantial scylacosaurid turnover between the Tapinocephalus and Endothiodon AZs, corresponding to the end-Guadalupian extinction.