A new pylaecephalid dicynodont (Therapsida, Anomodontia) from theTapinocephalusAssemblage Zone, Karoo Basin, Middle Permian of South Africa

2010 ◽  
Vol 30 (5) ◽  
pp. 1396-1409 ◽  
Author(s):  
KENNETH D. ANGIELCZYK ◽  
BRUCE S. RUBIDGE
Keyword(s):  
South Africa ◽  
Middle Permian ◽  
Karoo Basin

Cranial morphology and phylogenetic relationships of the Middle Permian pareiasaur Embrithosaurus schwarzi from the Karoo Basin of South Africa

2019 ◽  
Author(s):  
Marc Johan Van den Brandt ◽  
Fernando Abdala ◽  
Bruce Sidney Rubidge
Keyword(s):  
South Africa ◽  
South African ◽  
Middle Permian ◽  
Cranial Morphology ◽  
Karoo Basin ◽  
Assemblage Zone ◽  
Mandibular Teeth ◽  
First Time ◽  
Globally Distributed ◽  
Distinct Taxon

Abstract Pareiasaurs were globally distributed, abundant, herbivorous parareptiles of the Middle to Late Permian, with the basal-most members found in the Middle Permian of South Africa. These basal taxa were particularly abundant and went extinct at the end of the Gaudalupian (Capitanian) at the top of the Tapinocephalus Assemblage Zone. Currently four taxa are recognized in this group: Bradysaurus seeleyi, B. baini, Nochelesaurus alexanderi and Embrithosaurus schwarzi, but they are all poorly understood. We here present the first detailed cranial description and updated diagnosis for Embrithosaurus schwarzi. No cranial autapomorphies were identified. However, Embrithosaurus schwarzi is a distinct taxon in this group, based on its unique dentition and using a combination of cranial features. It has nine marginal cusps on all maxillary and mandibular teeth, and wider maxillary teeth than in the co-occurring taxa, due to the marginal cusps being arranged more regularly around the crown, and the apex of the crown lacking the long, central, three-cusped trident. Our updated phylogenetic analysis recovers the four Middle Permian South African taxa as a monophyletic group for the first time, which we call Bradysauria, comprising a clade including Embrithosaurus, Bradysaurus baini and a polytomy including Nochelesaurus and Bradysaurus seeleyi.

scholarly journals Tiarajudens eccentricus and Anomocephalus africanus , two bizarre anomodonts (Synapsida, Therapsida) with dental occlusion from the Permian of Gondwana

2015 ◽  
Vol 2 (7) ◽  
pp. 150090 ◽  
Author(s):  
Juan Carlos Cisneros ◽  
Fernando Abdala ◽  
Tea Jashashvili ◽  
Ana de Oliveira Bueno ◽  
Paula Dentzien-Dias
Keyword(s):  
Computed Tomography ◽  
South Africa ◽  
Middle Permian ◽  
Dental Occlusion ◽  
Tooth Replacement ◽  
Additional Insight ◽  
Karoo Basin ◽  
Computed Tomography Scans ◽  
Insight Into

Anomodontia was a highly successful tetrapod clade during the Permian and the Triassic. New morphological information regarding two bizarre basal anomodonts is provided and their palaeoecological significance is explored. The osteology of the recently discovered Tiarajudens eccentricus Cisneros et al . 2011, from the Brazilian Permian, is described in detail. The taxon exhibits unusual postcranial features, including the presence of gastralia. Additional preparation and computed tomography scans of the holotype of Anomocephalus africanus Modesto et al . 1999 discovered in the Karoo Basin of South Africa allow a reappraisal of this genus. Anomocephalus is similar to Tiarajudens with regard to several traits, including a battery of large, transversally expanded, palatal teeth. Molariform teeth are present in the mandible of the African taxon, providing additional insight into the function of the earliest tooth-occlusion mechanism known in therapsids. At least two waves of tooth replacement can be recognized in the palate of Anomocephalus . The outsized, blade-like caniniforms of the herbivorous Tiarajudens allow several non-exclusive ecological interpretations, among which we favour intraspecific display or combat. This behaviour was an alternative to the head-butting practised by the contemporary dinocephalians. Combat specializations that are considered typical of Cenozoic herbivores likely evolved during the Middle Permian, at the time the first communities with diverse, abundant tetrapod herbivores were being assembled.

scholarly journals New Specimen of the Enigmatic Dicynodont Lanthanostegus mohoii (Therapsida, Anomodontia) from the Southwestern Karoo Basin of South Africa, and its Implications for Middle Permian Biostratigraphy

2021 ◽  
Vol 9 ◽  
Author(s):  
Bruce S. Rubidge ◽  
Michael O. Day ◽  
Julien Benoit
Keyword(s):  
South Africa ◽  
Depositional Environment ◽  
Middle Permian ◽  
Western Cape ◽  
Eastern Cape ◽  
Karoo Basin ◽  
Lower Jaw ◽  
Assemblage Zone ◽  
Western Side ◽  
Single Locality

Lanthanostegus is an unusual dicynodont known from only two partial skulls from a single locality near Jansenville in the Eastern Cape Province of South Africa. Although these specimens can be constrained to near the base of the late middle Permian (Guadalupian) Abrahamskraal Formation, their precise age is uncertain as a result of diachroneity of the base of the Formation and the absence, in the Jansenville area, of index taxa to correlate this horizon with the biostratigraphy established in the Western Cape Province. Here, we describe a third skull that we identify as Lanthanostegus, which we recently discovered from a locality north of Laingsburg, on the western side of the main Karoo Basin. This skull reveals morphological details of the palate, occiput, and lower jaw that are not preserved in the described specimens of Lanthanostegus mohoii and will advance understanding of this poorly known dicynodont. This discovery provides the first direct correlation between the lower Abrahamskraal Formation at Jansenville on the eastern side of the basin and the southwestern part of the basin, and suggests that Lanthanostegus occurs in the lowest Tapinocephalus Assemblage Zone (AZ), or possibly to a new assemblage transitional between the Eodicynodon and Tapinocephalus AZs. This supports earlier work proposing that the Eodicynodon AZ is present only on the western side of the Karoo Basin and that the transition from a marine to continental depositional environment occurred later toward the East.

Biostratigraphy of the Eodicynodon Assemblage Zone (Beaufort Group, Karoo Supergroup), South Africa

2020 ◽  
Vol 123 (2) ◽  
pp. 141-148
Author(s):  
B.S. Rubidge ◽  
M.O. Day
Keyword(s):  
South Africa ◽  
Large Scale ◽  
Middle Permian ◽  
Southwestern Part ◽  
Delta Plain ◽  
Karoo Basin ◽  
Maximum Thickness ◽  
The North ◽  
Terrestrial Environments ◽  
Assemblage Zone

Abstract The middle Permian Eodicynodon Assemblage Zone is the lowermost biozone of the Beaufort Group (Adelaide Subgroup, Karoo Supergroup) and occurs in the southwestern part of the main Karoo Basin. It is host to a diverse assemblage of basal therapsid genera of which Eodicynodon is the most abundant. The biozone reaches a maximum thickness of 1 100 m in the Prince Albert Road area and thins to the east and west. The biozone corresponds to the Combrinkskraal and Grootfontein members of the Abrahamskraal Formation, directly overlies the Waterford Formation of the Ecca Group, and records the earliest middle Permian terrestrial environments of Gondwana. Rocks of the biozone were deposited along the southern shoreline of the Karoo Basin in a subaerial delta plain environment as part of large-scale fan systems draining to the north and northeast within a second-order highstand systems tract.

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