Volume 56: 2023

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https://hdl.handle.net/10539/35651

Festschrift in Honour of Professor Bruce S Rubidge

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A Tribute to Professor Bruce Sidney Rubidge
(2023-07) Hancox, P. John; Day, Michael O.
Professor Bruce Sidney Rubidge has published hundreds of articles and papers covering various aspects of the geology of the Cape and Karoo supergroups and their palaeontological signatures. His work has significantly advanced our understanding of numerous taxonomic groups, as well as the litho- and biostratigraphy of the Karoo Supergroup. He has also driven the robust radiometric dating of the lower half of the Karoo Supergroup, and via supervision and collaboration with postgraduate students, our understanding of the basin fill and the end-Guadalupian extinction in South Africa. Bruce has also supervised numerous honours, masters and doctoral students (Fig. 1) and provided strong research leadership to many South African and international collaborators. Bruce’s vision and dedication to first the Bernard Price Institute for Palaeontological Research (BPI) and now the Evolutionary Studies Institute (ESI) have guided it to become the connected 21st century establishment that it is today.
Bruce Sidney Rubidge – a Personal Appreciation
(2023-07) Raath, Michael A.
A personal appreciation of the career of Professor Bruce Sidney Rubidge, as told by his former colleague Michael A. Raath.
Front Cover
(2023-07)
Imprint page
(2023-07)
Inside the front cover
(2023-07)
Late Permian terrestrial faunal connections invigorated: the first whaitsioid therocephalian from China
(2023-07) Liu, Jun; Abdala, Fernando
The record of therocephalian therapsids from the late Permian of China has recently been greatly expanded by the discovery of several new taxa of Akidnognathidae, a group previously known principally from South Africa and Russia. Continuing this string of discoveries, we present here the first Chinese record of a whaitsiid therocephalian. This is also the first record published of a tetrapod from Jingtai, Gansu, a late Permian locality that also yields remains of other groups such as dicynodonts, captorhinids, and chroniosuchians. This is the third taxon of whaitsiid therocephalian recognized in North Pangea. The new therocephalian is similar to the Russian Moschowhaitsia vjuschkovi in overall appearance, and although they are only recovered as sister-taxa in 6 out of 30 most parsimonious trees in our phylogenetic analysis, it is tentatively referred to Moschowhaitsia as a new species,M. lidaqingi. The phylogeny obtained is largely similar to previous hypotheses, recovering three main lineages of Eutherocephalia: Akidnognathidae, Whaitsioidea and Baurioidea. However, it differs from previous analyses in finding Chthonosauridae (comprising the Russian Chthonosaurus and Zambian Ichibengops) to be deeply nested within Whaitsioidea. Therocephalians were among the largest carnivores in the late Permian of North China, and may have represented the top predators in some faunas.
Preface
(2023-07) Choiniere, Jonah N; Chapelle, Kimberley E.J.; Kammerer, Christian F.
A preface to the Bruce Sidney Rubidge Festschrift volume with anecdotes about his early years.
Re-discovery of the Euparkeria bonebed locality (Mid-Triassic) in Aliwal North, South Africa, with an update of the taphonomy and depositional environment
(2023-07) Wolvaardt, Frederik P.; Smith, Roger M. H.; Arcucci, Andrea
Euparkeria capensis is an Early to Middle Triassic archosauriform reptile widely regarded as phylogenetically close to the base of the Archosauria. Fossils of this species are only known from a single locality in the townlands of Aliwal North, South Africa. The exact location was, until now, uncertain due to mis-reading of the field notes of the collector Mr Alfred ‘Gogga’ Brown and conflicting anecdotal information gleaned from local townsfolk. Careful transcription of the voluminous handwritten field notes, followed by archival research in the town museum, and ground-truthing of the targeted area, has led to the re-discovery of the Euparkeria type locality. Sedimentological facies analysis of the locality combined with taphonomic observations of the 38 fossil-bearing rock slabs collected by Brown, now housed in the Iziko South African Museum reveal the following scenario for the origin of the Euparkeria/ Mesosuchus bonebed: the bones are preserved within the base of two tabular massive sandstone beds in upper point-bar facies of a high sinuosity channel-fill. The stratigraphic position, sedimentology, and geometry of the sandstone beds with their interdigitation with overlying floodplain mudrocks is interpreted as part of an infilled chute-channel cutting across a point-bar of a meandering river. The taphonomic analysis of the main bonebed suggests that the initial concentration of tetrapod remains was controlled by a combination of a mass mortality event of a pack of Euparkeria, and a few Mesosuchus becoming overwhelmed by a flash flood, and the hydrodynamics of the small floating carcasses getting trapped within the confines of a downstream chute-channel. The re-discovered Euparkeria locality is stratigraphically positioned at the top of a locally significant sandstone marker bed informally named the Eldorado marker. This unit is generally accepted as the contact between the lower and middle Burgersdorp Fm. Biostratigraphically, the locality is positioned within the transition between the lower and middle subzones of the Cynognathus AZ, namely Langbergia-Garjainia below and Trirachodon- Kannemeyeria above. This is some 23mlower in the stratigraphy than previously thought, and the possible association with Langbergiatype burrow casts leads us to tentatively place it within the lower subzone.
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.
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.
Synchrotron scanning reveals the deep evolutionary root of the mammalian brain: the surprisingly advanced endocast morphology of Lumkuia fuzzi (Cynodontia: Probainognathia)
(2023-07) Benoit, Julien
The mammalian brain is very distinctive for its large relative size, enlarged olfactory bulbs, and layered isocortex. These defining traits likely evolved in the non-mammalian probainognathian cynodonts, although the timing and exact phylogenetic sequence in which these characters evolved is not well understood. The endocast of the brain cavity provides a unique window into the evolution of the central nervous system of extinct species. The endocast of the basal-most probainognathian, Lumkuia fuzzi, is here described for the first time. Its olfactory bulbs are relatively large despite that its encephalization quotient is lower than in Mammaliaformes. This contradicts the consensually established hypothesis that encephalization and olfaction evolved in concert. Moreover, the data presented here do not indisputably distinguish between the encephalization quotients of Mesozoic mammals, non-mammalian mammaliaforms, and non-mammaliaform cynodonts, which suggests that brain enlargement was gradual in this lineage. Lumkuia also possesses marked cerebral hemispheres, which is traditionally interpreted as the sign of the presence of an isocortex and hair. The enlarged olfactory bulbs and cerebral hemisphere in Lumkuia strongly support that the defining features of the mammalian brain began evolving in the last common ancestor of the Probainognathia clade, as early as the early Anisian.
Table of Contents
(2023-07)
The mandible of Compsodon helmoedi (Therapsida: Anomodontia), with new records from the Ruhuhu Basin, Tanzania
(2023-07) Angielczyk, Kenneth D.; Peecook, Brandon R.; Smith, Roger M. H.
The emydopoid dicynodont Compsodon helmoedi originally was named from a single skull collected in Daptocephalus Assemblage Zone strata in the South African Karoo Basin. Recently described specimens from the Luangwa Basin, Zambia, have elucidated the species’ cranial morphology and facilitated identification of other historical Karoo specimens. Neither the holotype nor any of the described Zambian specimens preserve a mandible; a referred Karoo specimen preserves a highly damaged mandible, but poor preservation obscures most details.We present an additional Zambian Compsodon specimen that includes an articulated cranium and mandible, and use μCT data to describe the mandible of this taxon for the first time. The mandible has an upturned dentary symphysis; ‘postcanine’ teeth with coarse distal denticles; a shallow, elongate posterior dentary sulcus with medial expansion anterior to the tooth row, and a prominent lateral dentary shelf. Although the mandible is similar to those of Emydops and Pristerodon, it can be differentiated from Emydops by the latter’s more triangular posterior dentary sulcus, and the absence of a rugose muscle scar on the lateral edge of the lateral dentary shelf. It differs from Pristerodon in the absence of a dentary table rostral to the tooth row, the presence of a transverse ridge dividing the lateral dentary shelf into posterior and anterior sections, and the anterodorsal angulation of the lateral dentary shelf. Three fragmentary specimens from the Usili Formation (Ruhuhu Basin) display the same morphotype and represent the first record of Compsodon from Tanzania. The expanding geographic range of Compsodon underscores its potential as a biostratigraphic index fossil, but more information on its stratigraphic and temporal ranges is needed to realize that potential.

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