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

2020 ◽  
Vol 123 (2) ◽  
pp. 217-238 ◽  
Author(s):  
P.J. Hancox ◽  
J. Neveling ◽  
B.S. Rubidge

Abstract The Cynognathus Assemblage Zone is the youngest tetrapod biozone of the Beaufort Group (Tarkastad Subgroup, Karoo Supergroup). It is situated between the underlying Lystrosaurus declivis Assemblage Zone and the base of the overlying Molteno Formation (Stormberg Group) and corresponds to the entire Burgersdorp Formation. It is characterised by the presence throughout of the cynodont genus Cynognathus. The biozone reaches a maximum thickness of around 650 m in the southeast part of the basin and thins dramatically to the north, where it is only a maximum of 50 m thick. We here propose a three-fold subdivision into a lower Langbergia-Garjainia Subzone, a middle Trirachodon-Kannemeyeria Subzone and an upper Cricodon-Ufudocyclops Subzone. The basal contact is defined biostratigraphically by the first appearance of Cynognathus crateronotus and Langbergia modisei. The Cynognathus Assemblage Zone lacks a defined biostratigraphic upper limit, being unconformably terminated by the base of the overlying Molteno Formation, which lacks a terrestrial vertebrate fossil record other than trackways.

2020 ◽  
Vol 123 (2) ◽  
pp. 141-148
Author(s):  
B.S. Rubidge ◽  
M.O. Day

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.


2021 ◽  
Vol 9 ◽  
Author(s):  
Christian A. Sidor ◽  
Neil J. Tabor ◽  
Roger M. H. Smith

A new burnetiamorph therapsid, Isengops luangwensis, gen. et sp. nov., is described on the basis of a partial skull from the upper Madumabisa Mudstone Formation of the Luangwa Basin of northeastern Zambia. Isengops is diagnosed by reduced palatal dentition, a ridge-like palatine-pterygoid boss, a palatal exposure of the jugal that extends far anteriorly, a tall trigonal pyramid-shaped supraorbital boss, and a recess along the dorsal margin of the lateral temporal fenestra. The upper Madumabisa Mudstone Formation was deposited in a rift basin with lithofacies characterized by unchannelized flow, periods of subaerial desiccation and non-deposition, and pedogenesis, and can be biostratigraphically tied to the upper Cistecephalus Assemblage Zone of South Africa, suggesting a Wuchiapingian age. Isengops is the second burnetiamorph recognized from Zambia and is part of a tetrapod assemblage remarkably similar to others across southern Pangea during the Wuchiapingian. A revised cladistic analysis of Biarmosuchia yielded over 500 most parsimonious trees that generally reaffirm the results of previous analyses for burnetiamorphs: Lemurosaurus is basal, Lobalopex and Isengops are proximate burnetiid outgroups, and Bullacephalus, Burnetia, Mobaceras, Niuksenitia, and Pachydectes are burnetiines. Furthermore, Russian biarmosuchians are scattered throughout the tree and do not form sister taxon relationships with each other. Burnetiamorphs display a wide disparity of cranial adornments and are relatively speciose (13 species), especially when compared to the number of specimens discovered to date (∼16 specimens). As has been suggested in some other tetrapod clades (e.g., ceratopsian dinosaurs), the burnetiamorph fossil record supports an inferred macroevolutionary relationship between cranial adornment and increased speciation rate.


2020 ◽  
Vol 123 (2) ◽  
pp. 239-248 ◽  
Author(s):  
P.A. Viglietti ◽  
B.W. McPhee ◽  
E.M. Bordy ◽  
L. Sciscio ◽  
P.M. Barrett ◽  
...  

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).


2020 ◽  
Vol 123 (2) ◽  
pp. 249-262 ◽  
Author(s):  
P.A. Viglietti ◽  
B.W. McPhee ◽  
E.M. Bordy ◽  
L. Sciscio ◽  
P.M. Barrett ◽  
...  

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).


2020 ◽  
Vol 123 (2) ◽  
pp. 165-180 ◽  
Author(s):  
M.O. Day ◽  
R.M.H. Smith

Abstract The Endothiodon Assemblage Zone is the third oldest tetrapod biozone of the Beaufort Group (Adelaide Subgroup, Karoo Supergroup). It is situated between the underlying Tapinocephalus and overlying Cistecephalus assemblage zones and in the southwestern part of the basin corresponds to the majority of the Poortjie and Hoedemaker members of the Teekloof Formation. It is characterised by the dicynodont genus Endothiodon, especially in the lower part of assemblage zone, and records early ecosystem recovery from the Capitanian mass extinction. It also contains the lowest occurrence in the Karoo Basin of cynodont therapsids, eutherocephalians, bidentalian dicynodonts, and diapsids. The biozone reaches a maximum thickness of around 250 m in the southwestern part of the basin. We propose a two-fold subdivision into a lower Lycosuchus - Eunotosaurus Subzone (equivalent to the upper two-thirds of the former Pristerognathus Assemblage Zone) and an upper Tropidostoma - Gorgonops Subzone (equivalent to the former Tropidostoma Assemblage Zone), with the contact defined by the first appearance of Tropidostoma dubium. The Endothiodon Assemblage Zone is terminated by the first appearance of Aulacephalodon bainii.


2020 ◽  
Vol 123 (2) ◽  
pp. 149-164 ◽  
Author(s):  
M.O. Day ◽  
B.S. Rubidge

Abstract The Tapinocephalus Assemblage Zone is the second oldest tetrapod biozone of the Beaufort Group (Adelaide Subgroup, Karoo Supergroup), biostratigraphically positioned between the underlying Eodicynodon and overlying Endothiodon assemblage zones. It is characterised by a rich fossil tetrapod assemblage comprising basal members of most therapsid clades, but particularly dinocephalians such as Moschops capensis and basal pareiasaurs such as Bradysaurus in co-occurrence with the pylaecephalid dicynodonts Robertia and Eosimops. It corresponds to the upper two thirds of the Abrahamskraal Formation, is Capitanian (Guadalupian) in age, and reaches a maximum thickness of around 1500 m. The biozone is here separated into two subzones: a lower Eosimops – Glanosuchus Subzone and an upper Diictodon – Styracocephalus Subzone. The contact between the two subzones is defined by the first appearance of Diictodon feliceps, which closely corresponds to the base of the Moordenaars Member. The uppermost part of the biozone contains the Capitanian mass extinction and the low diversity fauna in its immediate aftermath. The zone is terminated by the first appearance of Endothiodon bathystoma.


2020 ◽  
Vol 123 (2) ◽  
pp. 181-190
Author(s):  
R.M.H. Smith

Abstract The late Permian (Lopingian) Cistecephalus Assemblage Zone (CiAZ) of the Karoo Supergroup in South Africa has recently been radiometrically-dated to range from 256 to 255 My. It encompasses approximately one million years of the late Wuchiapingian epoch, at a time when the ancient intra-continental lowlands of southern Gondwana had fully recovered from the end-Guadalupian mass extinction. The diverse Cistecephalus Assemblage Zone fauna is dominated by the small herbivorous dicynodonts Diictodon, Pristerodon and the molelike Cistecephalus, along with a range of larger dicynodont herbivores including Oudenodon, Aulacephalodon, Rhachiocephalus, Dinanomodon and rare Endothiodon. The attendant large carnivores include the gorgonopsians Aelurognathus, Rubidgea, and Smilesaurus, while smaller carnivores are represented by eutherocephalians (e.g., Ictidosuchoides, Ictidosuchops) and small gorgonopsians (e.g., Aloposaurus, Scylacocephalus). Of the parareptiles, the large-bodied taxon Pareiasaurus is most common, with the diminutive pareiasaurs Anthodon, Nanoparia, and Pumiliopareia making their first appearance. Lithostratigraphically, the biozone for the most part coincides with the arenaceous Oukloof and lower Steenkampsvlakte members in the western sub-basin and the equivalent Oudeberg and lower Daggaboersnek members in the east, where it reaches its maximum thickness of 300 m. The Cistecephalus Assemblage Zone thins westwards to 120 m at Teekloof Pass, and eastwards to approximately 100 m near the town of Fort Beaufort.


2019 ◽  
Vol 118 (11) ◽  
pp. 365-371
Author(s):  
J Dorasamy ◽  
Mr Jirushlan Dorasamy

Studies, especially in the North America, have shown a relationship between political orientation and moralfoundation. This study investigated whether moral judgements differ from the political orientation of participantsin South Africa moral judgment and the extent to which moral foundations are influenced by politicalorientation.Further, the study investigated the possibility of similar patterns with the North AmericanConservative-Liberal spectrum and the moral foundation. There were 300participants, 78 males and 222 females,who completed an online questionnaire relating to moral foundation and political orientation. The results partiallysupported the hypothesis relating to Liberal and Conservative orientation in South Africa. Further, this studypartially predicted the Liberal-Conservative orientation with patterns in the moral foundation, whilst showingsimilar findings to the North American studies. A growing rate of a neutral/moderate society is evidenced in SouthAfrica and abroad, thereby showing the emergence of a more open approach to both a political and generalstance.”””


2016 ◽  
Vol 3 ◽  
pp. 229-291 ◽  
Author(s):  
Alan L. Titus ◽  
Jeffrey G. Eaton ◽  
Joseph Sertich

The Late Cretaceous succession of southern Utah was deposited in an active foreland basin circa 100 to 70 million years ago. Thick siliciclastic units represent a variety of marine, coastal, and alluvial plain environments, but are dominantly terrestrial, and also highly fossiliferous. Conditions for vertebrate fossil preservation appear to have optimized in alluvial plain settings more distant from the coast, and so in general the locus of good preservation of diverse assemblages shifts eastward through the Late Cretaceous. The Middle and Late Campanian record of the Paunsaugunt and Kaiparowits Plateau regions is especially good, exhibiting common soft tissue preservation, and comparable with that of the contemporaneous Judith River and Belly River Groups to the north. Collectively the Cenomanian through Campanian strata of southern Utah hold one of the most complete single region terrestrial vertebrate fossil records in the world.


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