South African Karoo Basin Research Articles

The postcranial anatomy of Gorgonops torvus (Synapsida, Gorgonopsia) from the late Permian of South Africa

Gorgonopsians are among the most recognizable groups of synapsids from the Permian period and have an extensive but mostly cranial fossil record. By contrast, relatively little is known about their postcranial anatomy. Here, we describe a nearly complete, semi-articulated skeleton of a gorgonopsian (identified as Gorgonops torvus) from the late Permian Endothiodon Assemblage Zone of the South African Karoo Basin and discuss its paleobiological implications. Known gorgonopsian postcrania indicate morphological conservatism in the group, but the skeletal anatomy of Gorgonops does differ from that of other gorgonopsians in some respects, such as in the triangular radiale and short terminal phalanges in the manus, and a weakly developed distinction between pubis and ischium in ventral aspect of the pelvic girdle. Similarities between the specimen described herein and a historically problematic specimen originally referred to “Scymnognathus cf. whaitsi” confirm referral of the latter specimen to Gorgonops. Since descriptions of gorgonopsian postcrania are rare, new interpretations of the lifestyle and ecology of Gorgonopsia can be drawn from our contribution. We conclude that gorgonopsians were likely ambush predators, able to chase their prey over short distances and pin them down with strong forelimbs before using their canines for the kill. This is evidenced by their different fore- and hindlimb morphology; the former stouter and more robust in comparison to the longer, more gracile, back legs. Furthermore, the completeness of the study specimen facilitates calculation of an estimated body mass of approximately 98 kg, similar to that of a modern lioness.

Kembawacela yajuwayeyi n. sp., a new cistecephalid species (Dicynodontia: Emydopoidea) from the Upper Permian of Malawi

Cistecephalidae are a relatively basal clade of dicynodonts, well-nested within emydopoids, and known to have multiple adaptations to a fossorial lifestyle. In recent years cistecephalid taxonomic diversity has been progressively increasing and important insights into the osteology, soft-tissue anatomy, and paleobiology of the clade have improved considerably. Here we describe a new species of the cistecephalid Kembawacela from the Chiweta Beds (northern Malawi, Wuchiapingian), a poorly sampled area of Karoo sediments. Due to the minute dimensions and delicate nature of specimen DMMM-PK-16-1, we utilized propagation phase-contrast synchrotron X-ray micro-computed tomography, revealing conspicuous contrast between rock matrix and bone and allowing reconstruction of its cranial osteology in great detail. DMMM-PK-16-1 is here recognized as a new species based on the morphology of the crista oesophagea of the pterygoid, which has an acute posterior process separate from its contralateral. Despite the affinities with Kembawacela kitchingi there are various distinguishable features absent in the taxon (e.g., posterior border of the pterygoids is smoothly concave, rather than interdigitating with the basipostsphenoid). The erection of a new species in this region seems to support the growing evidence for species-level diversity in East African Karoo basins when contrasted to the Main South African Karoo basin. Furthermore, the anatomical resolution obtained allowed us to reconstruct the osseous labyrinth, the paths for several nerve branches, arteries and veins for the first time in cistecephalids, and we develop new hypotheses for their paths and nomenclature for dicynodonts. We found remarkable resemblance in the brain endocast of DMMM-PK-16-1 and another cistecephalid, Kawingasaurus, which is distinct from other dicynodonts in which it is known.

The stratigraphic and geographic occurrences of Permo-Triassic tetrapods in the Bogda Mountains, NW China — Implications of a new cyclostratigraphic framework and Bayesian age model

The Junggar and Turpan basins of Xinjiang Uygur Autonomous Region, northwest China, host a well-preserved terrestrial Permo-Triassic boundary sequence exposed along the northern and southern flanks of the Bogda Mountains. During the Permo-Triassic transition, this region was located in mid-latitude northeast Pangaea, making it an important comparison to the well-studied higher latitude record of the South African Karoo Basin. Broad similarities are apparent between the tetrapod fossil records of both areas, such as the reported co-occurrence of Dicynodon-grade dicynodontoids and Lystrosaurus in the upper Permian and the high abundance of Lystrosaurus in the Lower Triassic. However, the exact placement of the Permo-Triassic boundary in Xinjiang and South Africa has been debated. In the Chinese sections, the Permo-Triassic boundary falls within the upper Guodikeng Formation (= upper Wutonggou low order cycle), but several horizons have been proposed based on biostratigraphy, chemostratigraphy, and paleomagnetic data. A new Bayesian age model that is calibrated by multiple radiometric dates and tied to detailed litho- and cyclostratigraphic data offers new insight into the location of the Permo-Triassic boundary in Xinjiang and the opportunity to reconsider tetrapod occurrences in a highly resolved chronostratigraphic framework. We investigated the positions of new and historic tetrapod collections relative to the revised Permo-Triassic boundary, including uncertainties about the locations of key historic specimens. The stratigraphic range of Dicynodon-grade dicynodontoids in Xinjiang is poorly constrained: most specimens, including the holotype of Jimusaria sinkianensis, cannot be precisely placed relative to the Permo-Triassic boundary. A new specimen of Turfanodon sp. for which we have reliable data occurs in the upper Permian. Despite their previous treatment as Permian in age, most Bogda chroniosuchians were collected in strata above the Permo-Triassic boundary and the therocephalian Dalongkoua fuae also may be Triassic. Some prior placements of the Permo-Triassic boundary in Xinjiang imply an upper Permian lowest occurrence for the cosmopolitan dicynodont Lystrosaurus, but all Lystrosaurus specimens that we can precisely locate fall above the Permo-Triassic boundary. The high abundance of Lystrosaurus in the well-dated Early Triassic of Xinjiang suggests an Early Triassic age for the interval of greatest Lystrosaurus abundance in the Karoo Basin, where the exact ages of putative Permo-Triassic strata are more controversial. The Xinjiang record is an important datum for determining whether there was a single, globally synchronous time of highest Lystrosaurus abundance.

New data on the Triassic temnospondyls from the Karoo rift basins of Tanzania and Zambia

Temnospondyl specimens collected recently in the Middle-?Late Triassic of the Ruhuhu (Tanzania) and Luangwa (Zambia) rift basins are described and figured. They are attributed to cf. Cherninia megarhina (Chernin & Cosgriff, 1975), Mastodonsauroidea indet., Stereospondyli indet., and cf. Stereospondyli, as well as intercentra of small adult individual(s) which may belong to a new taxon. Although fragmentary, this new material allows taxonomic updates to the Triassic temnospondyl assemblages of Tanzania and Zambia and documents an interesting phylogenetic and ecological diversity. For example, among the Triassic mastodonsauroids of Zambia, Cherninia megarhina coexisted with Stanocephalosaurus pronus (Howie, 1970) in nonmarine environments. Similar to that of the South African Karoo Basin, these temnospondyl assemblages also illustrate the rapid recovery of the group after the Permian-Triassic mass extinction and contribute to a better understanding of the impact of this extinction on the tetrapod faunas of southern Pangea.

Stable isotopes (δ18O and δ13C) give new perspective on the ecology and diet of Endothiodon bathystoma (Therapsida, Dicynodontia) from the late Permian of the South African Karoo Basin

The late Permian dicynodont Endothiodon is characterized by its specialized feeding system, most notably manifested in its long rows of post-canine teeth and corresponding keratinous surfaces. This specialisation has fuelled discussion of not only the masticatory biomechanics in Endothiodon but also of its diet and ecology. To shed light on the latter two, we compared the oxygen (δ18Op) and carbon (δ13Cc) stable isotope compositions of Endothiodon tooth and bone apatite with those of the co-occurring dicynodont Tropidostoma, another late Permian dicynodont of similar size. Preliminary results indicate that Endothiodon had significantly lower ratios for stable isotopes of both oxygen and carbon. The δ18Op values from Endothiodon suggest that its lifestyle was more water-dependent (i.e. obligate drinker) than Tropidostoma, pointing to the possibility of a semi-aquatic ecology, whereas δ13Cc values suggest that Endothiodon had a diet primarily comprising riparian vegetation, with the possibility that juveniles consumed terrestrial insects. The data suggest a negligible role for roots, seeds, or algae in the diet of Endothiodon.

Novel Endocranial Data on the Early Therocephalian Lycosuchus vanderrieti Underpin High Character Variability in Early Theriodont Evolution

Therocephalia is one of the major therapsid clades and ranges from the middle Permian to Middle Triassic. The earliest therocephalians were large-bodied predators whose fossils are common in middle Permian rocks of South Africa, but have received little study. Here we present a redescription of the skull of the early therocephalian Lycosuchus based on a specimen from the middle Permian Tapinocephalus Assemblage Zone of the South African Karoo Basin. By using a computed tomographic (CT) reconstruction of this specimen, we describe for the first time several endocranial characters of this taxon including a highly ramified maxillary canal and the inner ear, which is characterized by a lengthened lateral semicircular canal, a feature previously only known from the anomodont Kawingasaurus among non-mammalian therapsids, and the presence of a cochlear recess, so far only known within Therocephalia from the highly specialized Triassic taxon Microgomphodon. We also provide new insights into patterns of tooth replacement in lycosuchids, which have proven controversial for this taxon. Craniodental characters generally support the placement of Lycosuchus as the most basal taxon in therocephalian phylogeny. The morphology of the maxillary canal and inner ear reveal a mosaic of features indicating a complex history of character acquisition and loss in Therocephalia, comparable to that of cynodonts.

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

ABSTRACTTwo 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.

New geochemical and palaeontological data from the Permian-Triassic boundary in the South African Karoo Basin test the synchronicity of terrestrial and marine extinctions

The end-Permian mass extinction (EPME) is widely recognised as the largest mass extinction in Phanerozoic history. In marine strata the main extinction event is well constrained, and has been radiometrically-dated to an interval of some 60 kyr, approximately 251.9 million years ago. However, the age and duration of the EPME in the terrestrial realm, as well as its possible synchronicity with that of the marine realm, is debated. Here, we shed light on issues pertaining to the identification and position of the terrestrial EPME in southern Africa. Using recently collected sedimentological (facies sequences), palaeontological (biostratigraphic ranges), geochemical (stable isotope analyses) and detrital zircon (ID-TIMS) data from a new site in the Xhariep District of the South African Karoo Basin, we demonstrate that the Permian-Triassic boundary sequence containing evidence for phased tetrapod extinctions is time equivalent with the marine extinction. We conclude that the terrestrial EPME recorded in the Karoo may be regarded as essentially synchronous with the EPME currently defined in the marine realm, and was likely the result of the same volcanically-induced atmospheric disturbances. This study describes the first single, vertical succession of vertebrate and plant fossils that span the terrestrial Permian-Triassic boundary that are also well-constrained both by relative (stable isotopes) and absolute (detrital zircon geochronology) dating methods.

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

AbstractThe 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.

Cranial anatomy of the early cynodont Galesaurus planiceps and the origin of mammalian endocranial characters.

The cranial anatomy of the early non-mammalian cynodont Galesaurus planiceps from the South African Karoo Basin is redescribed on the basis of a computed tomographic reconstruction of the skull. Previously, little was known about internal skull morphology and the nervous and sensory system of this taxon. The endocranial anatomy of various cynodonts has been intensively studied in recent years to understand the origin of mammalian characters in the nasal capsule, brain and ear. However, these studies have focused on only a few taxa, the earliest of which is another Early Triassic cynodont, Thrinaxodon liorhinus. Galesaurus is phylogenetically stemward of Thrinaxodon and thus provides a useful test of whether the mammal-like features observed in Thrinaxodon were present even more basally in cynodont evolution. The cranial anatomy of G.planiceps is characterized by an intriguing mosaic of primitive and derived features within cynodonts. In contrast to the very similar internal nasal and braincase morphology of Galesaurus and Thrinaxodon, parts of the skull that seem to be fairly conservative in non-prozostrodont cynodonts, the morphology of the maxillary canal differs markedly between these taxa. Unusually, the maxillary canal of Galesaurus has relatively few ramifications, more similar to those of probainognathian cynodonts than that of Thrinaxodon. However, its caudal section is very short, a primitive feature shared with gorgonopsians and therocephalians. The otic labyrinth of Galesaurus is generally similar to that of Thrinaxodon, but differs in some notable features (e.g. proportional size of the anterior semicircular canal). An extremely large, protruding paraflocculus of the brain and a distinct medioventrally located notch on the anterior surface of the tabular, which forms the dorsal border of the large parafloccular lobe, are unique to Galesaurus among therapsids with reconstructed endocasts. These features may represent autapomorphies of Galesaurus, but additional sampling is needed at the base of Cynodontia to test this.

The tetrapod fauna of the upper Permian Naobaogou Formation of China: 1. Shiguaignathus wangi gen. et sp. nov., the first akidnognathid therocephalian from China.

The Permian from China has a well-known terrestrial record where approximately 30 tetrapod taxa, including several therapsids, have been described. However, the record of therocephalians in China has remained elusive. Shiguaignathus wangi gen. et sp. nov., discovered in the Member III of the Naobaogou Formation, Nei Mongol, China, is here described. This is the first therocephalian recovered from this fauna and only the second from the Permian of China. It is represented by a well-preserved robust snout of a medium-sized animal. This is the first akidnognathid reported from the Chinese Permian and only the second genus from Laurasia as one genus is known from Russia whereas the remaining members of the group are from the South African Karoo Basin. A phylogenetic analysis of therocephalians supports a basal position of S. wangi within Akidnognathidae, followed by the Russian Annatherapsidus. Akidnognathidae is the latest major group of therocephalian appearing in the fossil record, and one of the few that does not have species from South Africa representing its most basal members.

Re-Assessment of Silphoictidoides ruhuhuensis von Huene, 1950 (Therapsida, Therocephalia) from the Late Permian of Tanzania: One of the Most Basal Baurioids Known

Abstract The known material of the small therocephalian Silphoictidoides ruhuhuensis von Huene, 1950, is re-investigated. Additional description of the cranial osteology and a new diagnosis of the taxon are provided. It is demonstrated that contrary to recent claims Silphoictidoides represents a valid genus that is so far endemic to the Ruhuhu Basin and distinct from any described forms from the South African Karoo Basin. Phylogenetic analysis indicates that the genus is one of the most basal known representatives of the important therocephalian clade Baurioidea.

Comparative ecological dynamics of Permian-Triassic communities from the Karoo, Luangwa, and Ruhuhu Basins of southern Africa

ABSTRACTThe Permian-Triassic mass extinction (PTME) was one of the transformative events of the Phanerozoic, marked by extinction, post-Permian transformation of surviving ecosystems, and the formation of new communities. The South African Karoo Basin has served as the primary source of data on the terrestrial component of these events, but its global applicability remains poorly known. Here, we compare Permian-Triassic communities of the Karoo Basin with those from the Luangwa and Ruhuhu basins of Zambia and Tanzania, respectively, analyzing their functional structures and simulating dynamic responses to environmental perturbation. Results show that compositional similarities of late Permian communities among the basins underlie similarities in their dynamics and resistance to secondary extinction. The Karoo Basin ecosystem also displays evidence of a transformation to increased resistance during the late Permian. Although the Karoo Basin ecosystem was reduced significantly by the PTME, structural features of that resistance persisted into the Early Triassic, facilitated by a greater susceptibility to extinction of small-body-sized amniotes and large carnivorous amniotes. It was undone by the initial stages of postextinction restructuring. Continued evolution of the Triassic ecosystem led to a recovery of resistance, but in a community compositionally dissimilar from its Permian antecedents. Likewise, the upper part of the Lifua Member of the Manda Beds (Middle Triassic) of Tanzania was structurally distinct from the Karoo Basin communities but displayed similar dynamics. The recurrence and convergence of communities with different histories toward similar dynamics suggest that there are taxon-independent norms of community assembly and function operating on geological timescales.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: Roopnarine, P. D., K. D. Angielczyk, S. Olroyd, S. J. Nesbitt, J. Botha-Brink, B. R. Peecook, M. O. Day, and R. M. H. Smith. 2018. Comparative ecological dynamics of Permian-Triassic communities from the Karoo, Luangwa, and Ruhuhu basins of southern Africa; pp. 254–272 in C. A. Sidor and S. J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37(6, Supplement).

Burrowing in Lystrosaurus: preadaptation to a postextinction environment?

ABSTRACTLystrosaurus is iconic for surviving the Permo-Triassic Mass Extinction and becoming the most abundant terrestrial vertebrate during the Early Triassic. Previous reports of skeletal remains of the Triassic species being found in fossilized burrows hint at a possible reason for its success, but unequivocal evidence showing that Lystrosaurus individuals were the burrow makers was lacking. I present here the first articulated skeleton of Lystrosaurus in a fossilized burrow from the Lower Triassic of the South African Karoo Basin, along with taphonomic evidence indicating that this individual was the burrow maker. The species is identified as L. curvatus, the only Lystrosaurus species recovered from above and below the inferred Permo-Triassic extinction horizon. It provides the first evidence of burrowing in a Permian species of Lystrosaurus, suggesting that this behavior was more prevalent than previously thought. Based on its size, the specimen is inferred to be a juvenile, showing that Lystrosaurus was capable of excavating burrows at young ontogenetic stages. The abundance of Lystrosaurus body fossils and similar-sized burrows from Lower Triassic strata suggests that burrowing played a pivotal role in the success of this genus in harsh, unpredictable postextinction conditions. Given the abundance of these burrows throughout the Lower Triassic Lystrosaurus Assemblage Zone, Lystrosaurus may have acted as an ecosystem engineer and refuge provider for other species, which may help to explain the high species diversity in the lowermost Triassic in the Karoo Basin.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: J. Botha-Brink. 2017. Burrowing in Lystrosaurus: preadaptation to a postextinction environment?. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1365080.

Global climate perturbations during the Permo-Triassic mass extinctions recorded by continental tetrapods from South Africa

Several studies of the marine sedimentary record have documented the evolution of global climate during the Permo-Triassic mass extinction. By contrast, the continental records have been less exploited due to the scarcity of continuous sections from the latest Permian into the Early Triassic. The South African Karoo Basin exposes one of the most continuous geological successions of this time interval, thus offering the possibility to reconstruct climate variations in southern Laurasia from the Middle Permian to Middle Triassic interval. Both air temperature and humidity variations were estimated using stable oxygen (δ18Op) and carbon (δ13Cc) isotope compositions of vertebrate apatite. Significant fluctuations in both δ18Op and δ13Cc values mimic those of marine records and suggest that stable isotope compositions recorded in vertebrate apatite reflect global climate evolution. In terms of air temperature, oxygen isotopes show an abrupt increase of about +8°C toward the end of the Wuchiapingian. This occurred during a slight cooling trend from the Capitanian to the Permo-Triassic boundary (PTB). At the end of the Permian, an intense and fast warming of +16°C occurred and kept increasing during the Olenekian. These thermal fluctuations may be related to the Emeishan (South China) and Siberian volcanic paroxysms that took place at the end of the Capitanian and at the end of the Permian, respectively. Vertebrate apatite δ13Cc partly reflects the important fluctuations of the atmospheric δ13C values, the differences with marine curves being likely due to the evolution of local humidity. Both the oxygen and carbon isotope compositions indicate that the PTB was followed by a warm and arid phase that lasted 6Ma before temperatures decreased, during the Late Anisian, toward that of the end-Permian. Environmental fluctuations occurring around the PTB that affected both continental and marine realms with similar magnitude likely originated from volcanism and methane release.

A new endothiodont dicynodont (Therapsida, Anomodontia) from the Permian Ruhuhu Formation (Songea Group) of Tanzania and its feeding system

ABSTRACTCranial material of the dicynodont Endothiodon from the middle fossiliferous horizon of the Permian Ruhuhu Formation (Ruhuhu Basin, Tanzania) is described as a new species, E. tolani. Endothiodon tolani is distinguished from other Endothiodon species by the absence of a pineal boss and the presence of tusks in most specimens. Although some parts of the Ruhuhu Formation probably correlate with the Eodicynodon or Tapinocephalus assemblage zones of the South African Karoo Basin, it is uncertain whether E. tolani is older than E. bathystoma or E. mahalanobisi. There is less evidence for extensive anteroposterior translation of the mandible in E. tolani than in other dicynodonts. The jaw joint is specialized for allowing some medial-lateral motion. Mastication involved unilateral chewing. Flexure of the postdentary bones relative to the fused dentaries permitted the posterolaterally directed rows of teeth on one side of the skull and mandible to move past one another. The long tooth rows and prominent horn-covered ridges and grooves on the palate and mandible of Endothiodon are unique among dicynodonts. Comparisons with other taxa suggest that its feeding system may have been specialized for cutting three-dimensional objects such as stems or rhizomes. The dicynodont feeding system is very stereotyped throughout the clade's history, but Endothiodon escaped the constraints that affected other dicynodonts, allowing it to evolve a unique skull morphology. This evolutionary flexibility did not translate into high taxonomic richness (we recognize only three species of Endothiodon), but Endothiodon was able to achieve high levels of relative abundance in some basins.http://zoobank.org/urn:lsid:zoobank.org:pub:9686F708-2E6E-40EB-956F-05659889684FSUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

A brief lithostratigraphic review of the Abrahamskraal and Koonap formations of the Beaufort Group, South Africa: Towards a basin-wide stratigraphic scheme for the Middle Permian Karoo

The basal strata of the Beaufort Group of the South African Karoo Basin, comprising the western Abrahamskraal and eastern Koonap formations, contain the most time extensive record of Middle Permian fossil tetrapods and hold the key to understanding Middle Permian biodiversity change in the continental realm. To determine faunal stratigraphic ranges a reliable lithostratigraphic framework for Middle Permian Beaufort deposits is essential. Until now this has proved difficult to achieve, largely due to the homogeneity of the fluvial succession coupled with structural complexity as a result of Cape Fold Belt orogenesis. Accordingly, the Abrahamskraal Formation has been only locally subdivided on the basis of sandstone packages but regional stratigraphic subdivision has not yet achieved satisfactorily.Collation of stratigraphic sections from around the Karoo Basin for this study demonstrates the presence of four sandstone packages are present within the Abrahamskraal Formation in the south-western corner of the basin. These sandstone packages are given member status, based upon the nomenclature of Le Roux (1985) with the addition of the newly recognised Grootfontein Member. The Combrinkskraal and Grootfontein Members occur in the lower half of the Abrahamskraal Formation and are laterally persistent along the southern margin of the basin. The Koornplaats Member is more restricted to the south west corner of the basin, where it quite thick, suggesting the narrowing of the highly channelized area. The overlying Moordenaars Member, more extensive towards the north than underlying packages, indicates subsequent northwesterly expansion of the locus of active channelization with time. Although thin sandstone packages in the more easterly positioned and stratigraphically equivalent Koonap Formation, this does not facilitate lithostratigraphic subdivision of this part of the stratigraphic succession and may indicate a different form of fluvial architecture. Our study provides a regional lithostratigraphic scheme for the Abrahamskraal Formation that will facilitate its biostratigraphic subdivision and the investigation of Middle Permian Gondwanan basin evolution.

Palynological records of the Permian Ecca Group (South Africa): Utilizing climatic icehouse–greenhouse signals for cross basin correlations

The Permian formations of the South African Karoo Basin play a crucial role in understanding Gondwana's climate history during this time of major global changes. In this paper we present two data sets, one from the coal-bearing Vryheid Formation (Witbank Basin) and one from the Whitehill and Upper Prince Albert formations of the DP 1/78 core (NE Karoo).Our main goal was to study the vegetation changes during this period of global warming and test if the climatic signals could be used to correlate the basinal Ecca group facies with the fluvio-deltaic coal-bearing strata of the Witbank Basin. The palynological record of the No. 2 Coal Seam of the Vryheid Formation indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. The data set of the DP 1/78 core is interpreted to represent a cool to warm temperate climate represented by a high amount of Gangamopteris and Glossopteris elements.Both data sets are very different in their composition, which can be explained by the differences in depositional environment; however, our findings reveal a different age of the studied assemblages and thus also suggest that both data sets represent different stages in the transition from icehouse to greenhouse during Permian times. As the stratigraphic correlation between the Main Karroo Basin and the peripheral basins is still under discussion, this paper provides new data to underpin the stratigraphic placement of the Whitehill Formation relative to the coal-bearing Vryheid Formation.

Palynological records of the Early Permian postglacial climate amelioration (Karoo Basin, South Africa)

The Permian coal-bearing formations of the South African Karoo Basin play a crucial role in the study and interpretation of Gondwana’s climate history and biodiversity in this time of major global changes in terrestrial and marine ecosystems. Here, we report on new palynological data from the No. 2 coal seam of the Witbank coalfield, documenting the switch from icehouse to greenhouse conditions in the Early Permian. The studied postglacial fluvio-deltaic deposits of a highly proximal setting comprise coarse-grained to pebbly sandstones, partially with an abrupt upward transition into fine-grained sediments and coal, trough cross-stratified medium- to coarse-grained sandstones and horizontally laminated fine- to medium-grained sandstones and siltstones. The sedimentary organic matter content clearly documents stratal changes in the palynomorph assemblage and variations in the amount and in the type, size and shape of plant debris. Generally, palynofacies is characterized by a high amount of opaque phytoclasts. Amorphous organic matter is characteristic of laminated siltstones and coals. The palynological record indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. The data presented herein, provide important information for (1) reconstructing palaeoenvironmental and climate change within the Lower Permian of the NE part of the South African Karoo, (2) intercontinental comparison of palaeofloral diversity patterns in adjacent sub-basins and (3) intra-Gondwanic correlations of coal-bearing basins (e.g. Australia), recording a major postglacial change associated with climate amelioration.

The quality of the fossil record of anomodonts (Synapsida, Therapsida)

The quality of the fossil record of anomodont synapsids, one of the major clades of Permian–Triassic terrestrial tetrapods, is assessed. A Character Completeness Metric (CCM2) is calculated for each taxon and consecutive time intervals at a global scale and in the South African Karoo Basin. The mean completeness score is 66.80% (globally) and 77.37% (regionally) with completeness ranging between 60.12% and 91.33% per time interval. Up-to-date taxic, phylogenetic and residual diversity estimates confirm the general biodiversity trends recovered by recent analyses. The consistently high CCM2 scores throughout their evolutionary history together with a lack of correlation with biodiversity patterns and sampling proxies document a high quality of the known anomodont fossil record. In fact, when compared to other vertebrate groups, the completeness values for anomodonts are exceptionally high. Yet, whether this pattern results from the unrivalled record of the Karoo Basin or whether it is clade-specific and unique to anomodonts remains to be tested.