scholarly journals Inter-element variation in the bone histology of Anteosaurus (Dinocephalia, Anteosauridae) from the Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12082
Author(s):  
Mohd Shafi Bhat ◽  
Christen D. Shelton ◽  
Anusuya Chinsamy
Keyword(s):  
South Africa ◽  
Bone Tissue ◽  
Early Ontogeny ◽  
Bone Histology ◽  
Karoo Basin ◽  
Slowing Down ◽  
Ephemeral Pools ◽  
Assemblage Zone ◽  
Histological Results ◽  
Bone Deposition

Despite its abundance in the Permian fossil record of South Africa, little is known about the life history of Anteosaurus. Here we examine the bone microstructure of multiple skeletal elements of Anteosaurus from the Tapinocephalus Assemblage Zone of the Karoo Basin. The bone histology of Anteosaurus magnificus reveals that the cortex is composed of highly vascularized, uninterrupted fibrolamellar bone tissue surrounding the inner spongy medullary region. However, the histology of two ribs and a previously described femur of another Anteosaurus taxon revealed an interrupted growth pattern with lines of arrested growth and peripheral rest lines occurring in the compacta, indicating periodic pauses in growth possibly linked to the slowing down of growth during maturity. Given that the fibula of the same individual has well-vascularised fibrolamellar bone tissue without any growth marks in the cortex; this suggests variation in skeletal growth. Based on our histological results, three growth dynamic stages are deduced for the genus Anteosaurus: (i) the earliest growth stage is represented by the predominance of highly vascularized, uninterrupted fibrolamellar bone tissue in the inner cortex, which suggests rapid periosteal bone deposition during early ontogeny; (ii) the next stage of growth shows periodic interruptions in the bone deposition as indicated by the deposition of lines of arrested growth; (iii) the third stage shows the development of lamellar bone tissue with rest lines in the peripheral part of the cortex suggesting a slowing down of growth prior to death. Most of the skeletal elements are characterized by thick bone walls, extensive secondary reconstruction and the complete infilling of the medullary cavity. However, the radius and a previously studied femur have open medullary cavities with struts of bony trabeculae. Based on histologic structures and comparisons with extant taxa, it is likely that Anteosaurus may have been more terrestrial as its osteology point towards terrestriality, but it may have occasionally inhabited ephemeral pools like modern semi-aquatic Hippopotamus.

scholarly journals Preliminary bone histological analysis of Lystrosaurus (Therapsida: Dicynodontia) from the Lower Triassic of North China, and its implication for lifestyle and environments after the end-Permian extinction

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248681
Author(s):  
Fenglu Han ◽  
Qi Zhao ◽  
Jun Liu
Keyword(s):  
South Africa ◽  
Bone Tissue ◽  
Lower Triassic ◽  
Early Ontogeny ◽  
Growth Strategy ◽  
Bone Histology ◽  
Early Triassic ◽  
Tissue Changes ◽  
Permian Extinction ◽  
Permian Mass Extinction

Lystrosaurus represents one of the most successful dicynodonts, a survivor of the end-Permian mass extinction that remained abundant in the Early Triassic, but many aspects of its paleobiology are still controversial. The bone histology of Lystrosaurus species from South Africa and India has provided important information on their growth strategy and lifestyle, but until recently no data was available on the bone histology of Lystrosaurus from China. Here, we report on the bone microstructure of seven Lystrosaurus individuals from the Lower Triassic of Xinjiang, providing the first such data for the Chinese Lystrosaurus species. Our samples indicate that the microstructure of Lystrosaurus limb bones from China is characterized by fibrolamellar bone tissue similar to those from South Africa and India. Three ontogenetic stages were identified: juvenile, early subadult, and late subadult based on lines of arrested growth (LAGs) and bone tissue changes. Bone histology supports a rapid growth strategy for Lystrosaurus during early ontogeny. Unlike Early Triassic Lystrosaurus from South Africa, lines of arrested growth are common in our specimens, suggesting that many individuals of Chinese Lystrosaurus had reached the subadult stage and were interrupted in growth. The differences in bone histology between Lystrosaurus from South Africa and China may indicate different environmental conditions in these two regions.

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.

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.

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).

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.

TESTING FOR CARBONATE-RICH PALEOSOLS IN THE LOWER LYSTROSAURUS ASSEMBLAGE ZONE, KAROO BASIN, SOUTH AFRICA

2018 ◽  
Author(s):  
Scott Daniel Harrison ◽  
◽  
Robert A. Gastaldo ◽  
Johann Neveling
Keyword(s):  
South Africa ◽  
Karoo Basin ◽  
Assemblage Zone
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