A New Pylaecephalid Dicynodont (Therapsida, Anomodontia) from the Tapinocephalus Assemblage Zone, Karoo Basin, Middle Permian of South Africa (project)

10.7934/p488 ◽  
2014 ◽  
Author(s):  
D Angielczyk ◽  
S Rubidge
Keyword(s):  
South Africa ◽  
Middle Permian ◽  
Karoo Basin ◽  
Assemblage Zone

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 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.

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

Biostratigraphy of the Scalenodontoides Assemblage Zone (Stormberg Group, Karoo Supergroup), South Africa

2020 ◽  
Vol 123 (2) ◽  
pp. 239-248 ◽  
Author(s):  
P.A. Viglietti ◽  
B.W. McPhee ◽  
E.M. Bordy ◽  
L. Sciscio ◽  
P.M. Barrett ◽  
...  
Keyword(s):  
South Africa ◽  
Qualitative And Quantitative ◽  
Karoo Basin ◽  
Maximum Thickness ◽  
Nomen Dubium ◽  
Assemblage Zone

Abstract The Scalenodontoides Assemblage Zone (SAZ) is the oldest fossil tetrapod biozone of the Stormberg Group (Karoo Supergroup) and preserves the oldest dinosaur bearing deposits in the Karoo Basin. The SAZ represents a revision of the ‘Euskelosaurus’ Range Zone, whose taxonomic basis has been undermined because ‘Euskelosaurus’ is well demonstrated to be a nomen dubium. Recent qualitative and quantitative investigations into the biostratigraphy of the Elliot and Clarens formations have resulted in the first biostratigraphic review of all lower Elliot Formation (lEF) taxa in nearly 40 years. Thus, we replace the ‘Euskelosaurus’ Range Zone with a new biostratigraphic assemblage zone, the Scalenodontoides Assemblage Zone (SAZ). Named after the traversodontid cynodont Scalenodontoides macrodontes, which co-occurs with the sauropodomorphs Blikanasaurus cromptoni and Melanorosaurus readi. The SAZ is currently accepted to range in age between the upper Norian and Rhaetian. Our new biozone, which reaches a maximum thickness of ~200 m, is wholly contained within the lower Elliot Formation (Stormberg Group, Karoo Supergroup).

Revision of the first therocephalian,TheriognathusOwen (Therapsida: Whaitsiidae), and implications for cranial ontogeny and allometry in nonmammaliaform eutheriodonts

2015 ◽  
Vol 89 (4) ◽  
pp. 645-664 ◽  
Author(s):  
Adam K. Huttenlocker ◽  
Fernando Abdala
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Single Species ◽  
Late Permian ◽  
Triassic Boundary ◽  
Karoo Basin ◽  
Wide Range ◽  
The Status ◽  
Assemblage Zone ◽  
Jaw Function

AbstractHistorically, the whaitsiid therocephalianTheriognathusOwen was one of the earliest described nonmammalian therapsids, its morphology helping to link phylogenetically the Paleozoic synapsids of North America and southern Africa to their mammalian successors. However, decades of taxonomic over-splitting and superficial descriptions obscured the morphologic diversity of the genus, hindering its utility as a study system for the evolution of synapsid cranial function as well as its biostratigraphic significance in the Late Permian of southern Africa. Here, we revise the status and provenance of all the known specimens ofTheriognathusfrom South Africa, Tanzania, and Zambia. We present both qualitative and quantitative support for the presence of a single morphospecies as proposed by some authors. Proportional differences in skulls that were previously ascribed to different morphotypes (‘Aneugomphius,’ ‘Notosollasia,’ ‘Moschorhynchus,’ and ‘Whaitsia’) are largely size-related and allometric trends are considered here in the context of jaw function and prey prehension. Our results suggest that the single species,Theriognathus microps, represented one of the most abundant Late Permian therocephalians in southern Africa and is consequently a potentially useful biostratigraphic marker for the upperCistecephalus-lowerDicynodonAssemblage Zone transition (i.e., late Wuchiapingian). The wide range of preserved sizes in conjunction with recent paleohistological evidence supports that individuals spent much of their lives in an actively-growing, subadult phase. LaterDicynodonAssemblage Zone records (e.g., upper Balfour Formation) are unconfirmed as the genus was likely replaced by other theriodont predators (e.g.,Moschorhinus) leading up to the Permo-Triassic boundary in the Karoo Basin of South Africa.

Biostratigraphy of the Massospondylus Assemblage Zone (Stormberg Group, Karoo Supergroup), South Africa

2020 ◽  
Vol 123 (2) ◽  
pp. 249-262 ◽  
Author(s):  
P.A. Viglietti ◽  
B.W. McPhee ◽  
E.M. Bordy ◽  
L. Sciscio ◽  
P.M. Barrett ◽  
...  
Keyword(s):  
South Africa ◽  
Faunal Turnover ◽  
Qualitative And Quantitative ◽  
Karoo Basin ◽  
Maximum Thickness ◽  
Extinction Event ◽  
Assemblage Zone ◽  
Main Index ◽  
Stratigraphic Interval

Abstract The Massospondylus Assemblage Zone is the youngest tetrapod biozone in the Karoo Basin (upper Stormberg Group, Karoo Supergroup) and records one of the oldest dinosaur dominated ecosystems in southern Gondwana. Recent qualitative and quantitative investigations into the biostratigraphy of the lower and upper Elliot formations (lEF, uEF) and Clarens Formation in the main Karoo Basin resulted in the first biostratigraphic review of this stratigraphic interval in nearly four decades, allowing us to introduce a new biostratigraphic scheme, the Massospondylus Assemblage Zone (MAZ). The MAZ expands upon the Massospondylus Range Zone by including the crocodylomorph Protosuchus haughtoni and the ornithischian Lesothosaurus diagnosticus as two co-occurring index taxa alongside the main index taxon, the sauropodomorph Massospondylus carinatus. With a maximum thickness of ~320 m in the southeastern portion of the basin, our new biozone is contained within the uEF and Clarens formations (upper Stormberg Group), however, based on vertebrate ichnofossils evidence, it may potentially extend into the sedimentary units of the lowermost Drakensberg Group. We do not propose any further subdivisions, and do not consider the Tritylodon Acme Zone (TAZ) as a temporal biostratigraphic marker within the MAZ. The MAZ is currently accepted to range in age between the Hettangian and Pliensbachian, however a faunal turnover, which observes an increase in the diversity of dinosaur clades, crocodylomorph, and mammaliaform taxa in the lower uEF, could reflect effects of the end-Triassic extinction event (ETE).

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.

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