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

2020 ◽  
Vol 123 (2) ◽  
pp. 165-180 ◽  
Author(s):  
M.O. Day ◽  
R.M.H. Smith
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Ecosystem Recovery ◽  
Southwestern Part ◽  
Karoo Basin ◽  
The Third ◽  
Maximum Thickness ◽  
Assemblage Zone

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.

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.

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).

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).

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

2020 ◽  
Vol 123 (2) ◽  
pp. 149-164 ◽  
Author(s):  
M.O. Day ◽  
B.S. Rubidge
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Maximum Thickness ◽  
Low Diversity ◽  
Assemblage Zone

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.

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

2020 ◽  
Vol 123 (2) ◽  
pp. 181-190
Author(s):  
R.M.H. Smith
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Large Carnivores ◽  
Late Permian ◽  
Maximum Thickness ◽  
Assemblage Zone ◽  
The Town

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.

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

2020 ◽  
Vol 123 (2) ◽  
pp. 207-216 ◽  
Author(s):  
J. Botha ◽  
R.M.H. Smith
Keyword(s):  
Mass Extinction ◽  
Closely Related Species ◽  
Community Assemblage ◽  
Faunal Assemblages ◽  
Karoo Basin ◽  
Time Period ◽  
Ecological Changes ◽  
Assemblage Zone ◽  
Permian Mass Extinction ◽  
Land Vertebrate

Abstract The earliest Triassic (Induan) Lystrosaurus Assemblage Zone has long been recognised as a particularly significant biozone in palaeoecological and palaeoenvironmental studies as it contains a community assemblage that records the survival and recovery from the end-Permian mass extinction (EPME). Here renamed the Lystrosaurus declivis Assemblage Zone it represents the best record globally of the ecological changes in terrestrial community structure and stability during this time period. The assemblage is dominated by two species of small to medium-sized herbivorous dicynodonts L. declivis and L. murrayi that co-occur in equal abundance, along with a range of smaller and less common faunivorous and insectivorous taxa. The latter comprise cynodonts (Thrinaxodon, Galesaurus, and Platycraniellus), therocephalians (Olivierosuchus, Regisaurus and Promoschorhynchus), the diminutive parareptiles (Saurodektes, Sauropareion, Colleta, Phonodus and Procolophon) and eureptilian arrivals possibly representing immigrant taxa (Prolacerta, Heleosuchus and Noteosuchus), among others. The attendant large carnivores were sabre-toothed Moschorhinus and the long-snouted archosauromorph Proterosuchus. In the aftermath of the mass extinction, new small temnospondyl taxa established their first occurrences i.e. Broomistega, Lydekkerina, and Micropholis, and have relatively high abundances compared to earlier temnospondyl records in the Karoo. Lithostratigraphically, the biozone for the most part spans the upper Palingkloof Member of the Balfour Formation and the overlying Katberg Formation in the western part of the basin, and the Normandien Formation in the east. The Lystrosaurus declivis Assemblage Zone of the main Karoo Basin hosts the type locality of the global Lootsbergian land-vertebrate faunachron. The biozone is one of the most widespread terrestrial faunal assemblages of western Gondwana with closely related species occurring in India and Antarctica. Similar, but much more distantly related taxa, occur in Induan-aged strata of Russia, China and Brazil.

scholarly journals When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150834 ◽  
Author(s):  
Michael O. Day ◽  
Jahandar Ramezani ◽  
Samuel A. Bowring ◽  
Peter M. Sadler ◽  
Douglas H. Erwin ◽  
...  
Keyword(s):  
South Africa ◽  
Mass Extinction ◽  
Southern China ◽  
Large Igneous Province ◽  
Temporal Association ◽  
Carbonate Platforms ◽  
Biodiversity Crisis ◽  
Karoo Basin ◽  
Extinction Event ◽  
Permian Mass Extinction

A mid-Permian (Guadalupian epoch) extinction event at approximately 260 Ma has been mooted for two decades. This is based primarily on invertebrate biostratigraphy of Guadalupian–Lopingian marine carbonate platforms in southern China, which are temporally constrained by correlation to the associated Emeishan Large Igneous Province (LIP). Despite attempts to identify a similar biodiversity crisis in the terrestrial realm, the low resolution of mid-Permian tetrapod biostratigraphy and a lack of robust geochronological constraints have until now hampered both the correlation and quantification of terrestrial extinctions. Here we present an extensive compilation of tetrapod-stratigraphic data analysed by the constrained optimization (CONOP) algorithm that reveals a significant extinction event among tetrapods within the lower Beaufort Group of the Karoo Basin, South Africa, in the latest Capitanian. Our fossil dataset reveals a 74–80% loss of generic richness between the upper Tapinocephalus Assemblage Zone (AZ) and the mid- Pristerognathus AZ that is temporally constrained by a U–Pb zircon date (CA-TIMS method) of 260.259 ± 0.081 Ma from a tuff near the top of the Tapinocephalus AZ. This strengthens the biochronology of the Permian Beaufort Group and supports the existence of a mid-Permian mass extinction event on land near the end of the Guadalupian. Our results permit a temporal association between the extinction of dinocephalian therapsids and the LIP volcanism at Emeishan, as well as the marine end-Guadalupian extinctions.

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