Wits Evolutionary Studies Institute (ESI)

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End date: 2009Subject: search.filters.subject.Triassic

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    Cranial description and taxonomic re-evaluation of Kannemeyeria argintinensis (Therapsida: Dicynodontia)
    (Bernard Price Institute for Palaeontological Research, 2001) Renaut, Hancox, PJ AJ
    Examination of the holotype skull of the Triassic dicynodont Kannemeyeria argentinensis Bonaparte reveals that many of purported diagnostic characters are distortion-related. A redescription of the holotype indicates that its inclusion in the genus Kannemeyeria cannot be supported. Several characters are, however, identical to the Argentine taxon Vinceria, and we suggest that the two taxa may be congeneric. This finding challenges the validity of a global Kannemeyeria-biochron, but not necessarily the relationships of tetrapod faunal groups in South America and Africa.
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    A new procolophonid (Parareptilia) from the Lystrosaurus Assemblage Zone, Beaufort Group, South Africa
    (Bernard Price Institute for Palaeontological Research, 2000) Gow, Chris E
    This paper describes the skull of a new genus and species of procolophonid from the Lystrosaurus Assemblage Zone. It is strikingly different from its contemporaries, Procolophon trigoniceps and Owenetta rubidgei, but has a mosaic of characters of each.
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    Cranial anatomy of the giant Middle Triassic temnospondyl Cherninia megarhina and a review of feeding in mastodonsaurids
    (Bernard Price Institute for Palaeontological Research, 2001) Damiani, Ross J
    The skull of Cherninia (,Parotosuchus') megarhina, a giant but poorly known mastodonsaurid temnospondyl from the Upper Horizon of the Middle Triassic N'tawere Formation of the Upper Luangwa Valley, Zambia, is redescribed and refigured in detail for the first time. Cherninia megarhina is highly derived in most aspects of its cranial morphology and is characterised by the presence of a massively broad and elongated snout, relatively tiny orbits that are set well back on the skull roof, small, near-laterally directed tabular horns, an occipital sensory sulcus, and prominent, forked ridges on the skull roof. The palate is characterised by the presence of a ventral exoccipital-pterygoid contact, a short basicranial suture, a narrow parasphenoid body, a broad pterygoid body, and choanae that are placed far forward of the interpterygoid vacuities. The presence in Cherninia megarhina of numerous cranial autapomorphies justifies its separation from Parotosuchus. These autapomorphies are shared with Cherninia (‘Parotosuchus') denwaifrom the Middle Triassic Denwa Formation of India. The lateral orientation of the tabular horns and morphology of the otic region suggests that Cherninia megarhina is slightly more derived than the Indian species. Mastodonsaurids have traditionally been perceived as passive, benthic suction-feeders. However, recent work on the anatomy and functional morphology of the skeleton of mastodonsaurids suggests that they were designed for active swimming and predation. As such, it is hypothesised that prey capture was achieved using sideways sweeps of the head rather than suction-feeding.
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    First record of non-mammalian cynodonts (Therapsida) in the Sanga do Cabral Formation (Early Triassic) of southern Brazil
    (2002) Abdala, Fernando; Dias-de-Silva, Sergio; Cisneros, Juan C
    New material from the Sanga do Cabral Formation in southern Brazil is described, including one distal and three proximal portions of femora, and a distal portion of a humerus. Comparative studies indicate affinities of the proximal femora and the distal humerus with non-mammalian cynodonts, whereas the distal femur cannot be attributed with certainty to this group. These postcranial elements are the first record of non-mammalian cynodonts for the Sang a do Cabral Formation and demonstrate the presence of small- to medium-sized representatives of this group in the Early Triassic fauna of Brazil.
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    Further consideration of the capitosaurids from the Upper Luangwa Valley, Zambia
    (Bernard Price Institute for Palaeontological Research, 1975) Chernin, Susan; Cosgriff, J W
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    Dicynodont postcrania from the Triassic of Namibia and their implication for the systematics of Kannemeyeriiforme dicynodonts
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2009-12) Govender, Romala; Yates, Adam
    Recent years have seen a renewed interest in the postcranial anatomy of Triassic dicynodonts from Africa. This study investigates the previously undescribed dicynodont postcrania from the Omingonde Formation of Namibia. Two valid dicynodont species, based upon crania, are known from this formation: Dolichuranus primaevus and Kannemeyeria lophorhinus. Dolichuranus displays a primitive generalized cranial anatomy that has made it difficult to place in Triassic dicynodont phylogeny. Some of the postcranial specimens can be positively identified as D. primaevus on the basis that they were associated with skulls of this species. Two scapula morphologies can be distinguished among the postcranial specimens that are not positively associated with diagnostic cranial remains. One of these shares similarities with the scapula of Kannemeyeria simocephalus from South Africa and is provisionally referred to K. lophorhinus. The other displays unusual characters such as the absence of an acromion and a tubercle on the lateral surface of the scapula at the level where the acromion would be expected. Inclusion of the new postcranial data in a cladistic analysis of Triassic dicynodonts resolves the position of D. primaevus as a member of Sinokannemeyeriidae. It also causes an enigmatic unnamed postcranial taxon from equivalently aged beds in South Africa to fall within the Sinokannemeyeriidae. These results highlight the importance of including postcranial data in analyses of Triassic dicynodont relationships.
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    A second specimen of Blikanasaurus (Dinosauria: Sauropoda) and the biostratigraphy of the lower Elliot Formation
    (Bernard Price Institute for Palaeontological Research, university of the Witwatersrand, 2008-04) Yates, Adam M.
    A second specimen of the rare basal sauropod Blikanasaurus cromptoni, is recorded from a site in the Ladybrand district of the Eastern Free State, South Africa. The specimen consists of a right metatarsal 1 that originated from the upper 20mof the lower Elliot Formation. It can be referred to B. cromptoni on the basis of its small size and highly robust proportions, which distinguish this taxon from all other sauropodomorphs. This record extends the geographic distribution of B. cromptoni north into the region of the main Karoo Basin where the Elliot Formation is dramatically thinner. It also extends the known stratigraphic range of B. cromptoni up from the base of the Elliot Formation into a position near the top of the lower member. This new record, combined with other new discoveries, supports the hypothesis that the thin northern part of the lower Elliot Formation is a condensed section that is largely, if not entirely, coeval with the thicker southern sections.
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    Re-evaluation of the postcranial skeleton of the Triassic dicynodont Kannemeyria simocephalus from the Cynognathus Assemblage Zone (Subzone B) of South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Govender, Romala; Hancox, Phillip John; Yates, Adam M.
    Kannemeyeria simocephalus is probably the best known Middle Triassic dicynodont from South Africa and has been the standard against which other Triassic dicynodonts are compared. In the past studies have concentrated on the cranial morphology of K. simocephalus and its implications for Triassic dicynodont taxonomy and phylogeny. There has been little work on the postcranial anatomy of K. simocephalus, which remains poorly understood. An analysis of the postcranial skeleton of K. simocephalus has identified characters that diagnose the postcranial skeleton. These include a tubercle on the proximo-posterior corner of the medial surface of the acromion; almost straight lateral border of the femur. Material previously described as K. simocephalus by Pearson (1924) and Cruickshank (1975) was also included in this study. Some of the material was found to be significantly different from what is understood to be K. simocephalus and as a result has been included a separate study. It was therefore concluded that the referred specimen BP/1/5624 is currently the most complete and positively identified as K. simocephalus.
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    Taxonomic status of the reptile genus Procolophon from the Gondwanan Triassic
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2008-04) Cisneros, Juan Carlos
    The specific composition of the genus Procolophon in Brazil, South Africa and Antarctica is discussed in the light of new data. It is found that P. pricei and P. brasiliensis, two species described from Brazil, fit within the pattern of ontogenetic variation of the type species P. trigoniceps, and they are here considered junior synonyms. The South African species P. laticeps, characterized by the presence of a temporal fenestra, is no longer considered valid. The peculiar temporal openings of this species are regarded here as an anomalous condition without taxonomic significance. The only complete skull known from Antarctica shows a unique feature consisting of an elliptical depression in the palate. The interpretation of this structure is ambiguous because it may also be attributable to individual variation, and this specimen is provisionally kept within P. trigoniceps. Therefore, only the type species, P. trigoniceps, is recognized in Gondwana. This species occupies a wide geographic range, from the Paraná Basin to the Transantarctic Mountains.