Browsing by Author "Kammerer, Christian F."

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    The first skeletal evidence of a dicynodont from the lower Elliot Formation of South Africa
    (Evolutionary Studies Institute, 2018) Kammerer, Christian F.
    Historical fossil specimens from the lower Elliot Formation are identified as representing a large-bodied dicynodont, the first known from skeletal material in the Late Triassic of South Africa. Although fragmentary, these fossils differ from all other known Triassic dicynodonts and are here described as a new taxon, Pentasaurus goggai gen. et sp. nov. Pentasaurus can be distinguished from other Triassic dicynodonts by a number of mandibular characters, most importantly the well-developed, unusually anteriorly-positioned lateral dentary shelf. Phylogenetic analysis indicates that Pentasaurus is a placeriine stahleckeriid. Placeriines include the latestsurviving dicynodonts but their remains are primarily known from the Northern Hemisphere, with their only previously-known Southern Hemisphere representative being the Middle Triassic Zambian taxon Zambiasaurus. The discovery of a placeriine in the Late Triassic of SouthAfrica supports recent proposals that local climatic conditions, not broad-scale biogeographic patterns, best explain the observed distribution of Triassic tetrapods. The tetrapod fauna of the lower Elliot Formation is highly unusual among Triassic assemblages in combining ‘relictual’ taxa like dicynodonts and gomphodont cynodonts with abundant, diverse sauropodomorph dinosaurs.
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    A new dicynodont (Anomodontia: Emydopoidea) from the terminal Permian of KwaZulu-Natal, South Africa
    (Evolutionary Studies Institute, 2019-04) Kammerer, Christian F.
    A new taxon of dicynodont (Thliptosaurus imperforatus gen. et sp. nov.) is described based on a dorsoventrally-crushed skull from latest Permian (upper Daptocephalus Assemblage Zone) strata in KwaZulu-Natal, South Africa. Thliptosaurus is distinguished from all other dicynodonts by an elongate intertemporal bar with broad dorsal exposure of the parietals but apparently no pineal foramen. Absence of the pineal foramen in dicynodonts is exceedingly rare; the only other taxa which exhibit this feature either have substantially broader (Kawingasaurus fossilis) or narrower (Kombuisia frerensis) intertemporal regions. Inclusion of Thliptosaurus in a phylogenetic analysis of dicynodonts recovers it as a kingoriid emydopoid, a position supported by its anteriorly-restricted pterygoid keel, elongate, curved anterior process of the lacrimal, relatively posterior position of the median pterygoid plate, and occlusion of the mandibular fenestra by a lateral plate of the dentary. Intriguingly, even in the other kingoriids which retain a pineal foramen (Dicynodontoides spp. and Kombuisia antarctica), this structure is reduced in size relative to other dicynodonts, suggesting that the pineal eye was less important for thermoregulatory activity in this clade than in other anomodonts. Although part of a local fauna including taxa that are otherwise widespread in the Karoo Basin (Daptocephalus, Lystrosaurus), the unique presence of Thliptosaurus in the relatively poorly-sampled Daptocephalus Assemblage Zone deposits of KwaZulu-Natal suggests that this region may preserve endemic taxa, and should be prioritized for future fieldwork.
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    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.
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    Rediscovery of the holotype of Clelandina major Broom, 1948 (Gorgonopsia: Rubidgeinae) with implications for the identity of this species
    (Evolutionary Studies Institute, 2017-12) Kammerer, Christian F.
    No specimen number was given for the holotype of the rubidgeine gorgonopsian species Clelandina major Broom, 1948 in its original description. Historically, a specimen in the Rubidge Collection (RC 94) was considered to represent Broom’s type specimen for C. major. However, recent study has revealed that the holotype of C. major is in fact a different specimen in the McGregor Museum in Kimberley (MMK 5031). The morphology of this specimen is consistent with the genus Clelandina, contra work based on RC 94 that considered C. major referable toAelurognathus. Clelandina major is here considered synonymous with the type species Clelandina rubidgei.MMK5031 represents only the fifth known specimen of this rare and unusual gorgonopsian.
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    Replacement names for the therapsid genera Criocephalus Broom 1928 and Olivieria Brink 1965.
    (Bernard Price Institute for Palaeontological Research, 2002) Kammerer, Christian F.; Sidor, Christian A.
    Our knowledge of premammalian synapsid evolutionary history has benefited from over a hundred years of fossil collecting, especially within the Permo-Triassic sediments of South Africa's Beaufort Group (Rubidge 1995) and the Cis-Ural region of Eastern Europe (Ivachnenko et al. 1997). In the course of our research and discussions we have discovered several errors in the present state of non-mammalian synapsid taxonomy. Here we propose emendations concerning the genera Criocephalus Broom 1928 and Olivieria Brink 1965.
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    Two unrecognised burnetiamorph specimens from historic Karoo collections
    (2016-03) Kammerer, Christian F.
    Two historical specimens from Permian rocks of the Karoo Basin represent previously unrecognised members of the rare therapsid group Burnetiamorpha. These specimens cannot be referred to any existing burnetiamorph species, but are left in open nomenclature because of their incompleteness (both are isolated skull roofs). The first specimen is from the Tapinocephalus Assemblage Zone (AZ) and is characterized by heavily pachyostosed supraorbital bosses and a low nasal crest. The second specimen is from the Tropidostoma AZ and is generally similar to the Malawian taxon Lende, but is unique among described burnetiamorphs in having a frontoparietal ‘dome’ that surrounds the pineal foramen. Phylogenetic analysis of burnetiamorphs recovers support for a split between Proburnetia and Burnetia-like burnetiids, here named Proburnetiinae subfam. nov. and Burnetiinae Broom, 1923.