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 Cranial morphology of the middle Permian pareiasaur Nochelesaurus alexanderi from the Karoo Basin of South Africa

2021 ◽  
pp. 1-21
Author(s):  
Marc J. VAN DEN BRANDT ◽  
Bruce S. RUBIDGE ◽  
Julien BENOIT ◽  
Fernando ABDALA
Keyword(s):  
South Africa ◽  
South African ◽  
Local Group ◽  
Cranial Morphology ◽  
Karoo Basin ◽  
Lower Jaw ◽  
Basal Group ◽  
Assemblage Zone ◽  
Globally Distributed ◽  
Distinct Taxon

ABSTRACT Pareiasaurs were globally distributed, abundant, herbivorous parareptiles with the basal-most members found only in the mid-Permian of South Africa. These basal forms form a monophyletic group and were locally abundant and became extinct at the top of the Tapinocephalus Assemblage Zone at the end of the Guadalupian. Four species of basal pareiasaurs are currently recognised: Bradysaurus baini, B. seeleyi, Embrithosaurus schwarzi and Nochelesaurus alexanderi, but they are all poorly understood and there remains historic uncertainty as to their validity. In this paper, our second contribution designed to improve understanding of the basal group, we present the first detailed cranial description and updated diagnosis for Nochelesaurus alexanderi and demonstrate that it is a distinct taxon based on one cranial autapomorphy, a large transversely wide postparietal, and a combination of cranial characters. Within the local group of mid-Permian pareiasaurs, we recognise new dental features of Nochelesaurus alexanderi: non-symmetrical marginal cusp arrangements on upper and lower teeth resulting from an extra basal mesial cusp; an incipient horizontal cingulum on lower jaw teeth, sometimes with one or two tiny medial cingular cusps; and up to ten marginal cusps. Our study demonstrates that tooth morphology and orientation, cranial ornamentation, morphology of the cheek bosses, shape of the postfrontal and postparietal, and morphology of the distal paroccipital process of the opisthotic are the most useful to identify South African mid-Permian pareiasaurs.

scholarly journals A new large cynodont from the Late Permian (Lopingian) of the South African Karoo Basin and its phylogenetic significance

2019 ◽  
Vol 186 (4) ◽  
pp. 983-1005 ◽  
Author(s):  
Fernando Abdala ◽  
Leandro C Gaetano ◽  
Roger M H Smith ◽  
Bruce S Rubidge
Keyword(s):  
South African ◽  
Posterior Margin ◽  
Cranial Morphology ◽  
Late Permian ◽  
Posterior Portion ◽  
Skull Length ◽  
Karoo Basin ◽  
Secondary Palate ◽  
Assemblage Zone

Abstract The Karoo Basin of South Africa has the best global record of Lopingian (Late Permian) non-mammaliaform cynodonts, currently represented by five species. We describe Vetusodon elikhulu gen. et sp. nov., documented by four specimens from the Daptocephalus Assemblage Zone. With a basal skull length of ~18 cm, it is the largest Lopingian cynodont and is also larger than Induan representatives of the group. Vetusodon elikhulu has a cranial morphology that departs notably from that previously documented for Permo-Triassic cynodonts. It features a short and extremely wide snout, resembling that of the contemporaneous therocephalian Moschorhinus, and has large incisors and canines that contrast with the small unicusped postcanines, suggesting a more important role of the anterior dentition for feeding. The dentary is extremely long and robust, with the posterior margin located closer to the craniomandibular joint than in other Lopingian and Induan cynodonts (e.g. Thrinaxodon). The secondary palate morphology of V. elikhulu is unique, being short and incomplete and with the posterior portion of the maxilla partly covering the vomer. A phylogenetic analysis suggests that V. elikhulu is the sister taxon of Eucynodontia and thus the most derived of the Lopingian to Induan cynodonts yet discovered.

SMALL FOOTPRINTS EXPAND MIDDLE PERMIAN AMPHIBIAN DIVERSITY IN THE SOUTH AFRICAN KAROO

Palaios ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 1-11 ◽  
Author(s):  
JUAN CARLOS CISNEROS ◽  
MICHAEL O. DAY ◽  
JACO GROENEWALD ◽  
BRUCE S. RUBIDGE
Keyword(s):  
South African ◽  
Middle Permian ◽  
Aquatic Biota ◽  
The South ◽  
Adult Form ◽  
Karoo Basin ◽  
Assemblage Zone

ABSTRACT Two new tetrapod trackways are described from the Tapinocephalus Assemblage Zone of the South African Karoo Basin. We interpret both to be traces attributable to small anamniote tetrapods. The larger footprints are tentatively referred to aff. Batrachichnus salamandroides. These imprints are distinguished from other records of Batrachichnus by a pentadactyl pes that produces only impressions of digits III–V. Digits I and II are recognized only by their drag marks. This trace occurs in association with a second set of footprints of uncertain affinities. However, these smaller imprints are not sufficiently well preserved and could represent undertracks or partially eroded footprints. None of the footprints can be attributed to the adult forms of the two temnospondyl taxa known from the Guadalupian part of the Karoo Basin: Rhinesuchus whaitsi or Rhinesuchoides tenuiceps. We interpret the aff. Batrachichnus trackway to have been produced by a small, adult temnospondyl or microsaur (Recumbirostrae), whereas the smaller set of footprints was likely made by a juvenile rhinesuchid or an unknown amphibian, either a paedomorphic form or a tiny adult form. The discovery shows that a more diverse aquatic biota existed at this time in the Karoo than osteological records currently suggest.

The South African stereospondyl Lydekkerina huxleyi (Tetrapoda, Temnospondyli) from the Lower Triassic of Australia

2006 ◽  
Vol 143 (6) ◽  
pp. 877-886 ◽  
Author(s):  
A. A. WARREN ◽  
R. DAMIANI ◽  
A. M. YATES
Keyword(s):  
South Africa ◽  
South African ◽  
Posterior Margin ◽  
Lower Triassic ◽  
Ventral Surface ◽  
The South ◽  
Karoo Basin ◽  
Skull Roof ◽  
Assemblage Zone

The first tetrapod fossil from the Rewan Formation of the Galilee Basin, central Queensland, Australia, is identified as Lydekkerina huxleyi, a stereospondyl found elsewhere only in the Lystrosaurus Assemblage Zone of South Africa. Apomorphies shared with L. huxleyi are: anterior palatal vacuity with anterodorsal projections from its posterior margin; ventral surface of skull roof with series of thickened ridges (condition unknown in other lydekkerinids); and vomerine shagreen present (possible autapomorphic reversal). Restudy of the only other Australian lydekkerinid, Chomatobatrachus halei, shows it to be distinct from L. huxleyi. The Rewan Formation, undifferentiated in the Galilee Basin, can be correlated with the Rewan Group of the Bowen Basin, and to the early part of the Lystrosaurus Assemblage Zone of the Karoo Basin, South Africa, which are of Griesbachian age. Varying palaeoenvironments may contribute to the contrasting nature of the Australian and South African faunas.

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 Daptocephalus Assemblage Zone (Beaufort Group, Karoo Supergroup), South Africa

2020 ◽  
Vol 123 (2) ◽  
pp. 191-206 ◽  
Author(s):  
P.A. Viglietti
Keyword(s):  
South Africa ◽  
South African ◽  
Taxonomic Revision ◽  
Species Level ◽  
Karoo Basin ◽  
Assemblage Zone ◽  
Stratigraphic Ranges

Abstract The name Daptocephalus Assemblage Zone (DaAZ) is re-instated for vertebrate assemblages of the uppermost Permian strata (Balfour, upper Teekloof, and Normandien formations) of South Africa’s main Karoo Basin (MKB). This involved taxonomic revision of the dicynodontoid “Dicynodon” sensu lato, reviving Daptocephalus leoniceps, and revising the stratigraphic ranges of co-occurring index taxa (Theriognathus microps, Procynosuchus delaharpeae) of the Dicynodon Assemblage Zone (DiAZ) as it was known. This work has demonstrated the appearance of index taxa below the stratigraphically defined DiAZ. Moreover, the first appearance of Lystrosaurus maccaigi and Moschorhinus kitchingi in the upper reaches of the biozone calls for the establishment of a two-fold subdivision of the current DaAZ into lower (Dicynodon-Theriognathus) and upper (Lystrosaurus maccaigi-Moschorhinus) subzones. The biostratigraphic utility of Daptocephalus and other South African dicynodontoids outside of the MKB is limited due to basinal endemism at the species level and varying temporal ranges of dicynodontoids globally. Accordingly, their use is recommended only for correlation within the Karoo Basin at this stage.

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.

Sign in / Sign up

Export Citation Format

Share Document