A new skull of Megazostrodon (Mammalia, Triconodonta) from the Elliot Formation (Lower Jurassic) of Southern Africa

A skull of Megazostrodon with atlas and axis in articulation is described. The dental formula is 14/4 C 1/1 Pm 5/5 M 5/5. Tooth wear is more advanced than in the type specimen and the lower molar series contains evidence of tooth replacement. The braincase differs remarkably from that of Morganucodon, the only contemporaneous triconodont in which the skull is adequately known. The lower jaw has an angular process similar to that of Dinnetherium. The earliest triconodonts appear to represent a modest radiation following the attainment of mammalian status

A reassessment of Eunotosaurus africanus Seeley (Amniota: Parareptilia).

Main articleThis paper provides an almost complete description of the Permian fossil reptile Eunotosaurus for the first time. Taphonomy indicates that these were terrestrial animals; dentition suggests that they preyed on small invertebrates; while the broad, imbricating ribs point to a slow moving animal with a protective, turtle-like carapace. Temporal emargination and the fan-like iliac blade serve to align these animals with Parareptilia, sensu Laurin and Reisz ( 1995). Eunorosaurusand millerettids are sister taxa on the basis of s tapes and rib morphology, and together they constitute the sister taxon to Ankyramopha (Debraga and Reisz 1996), having eight characters in which they are less derived than the latter.Non

A partial skeleton of the tritheledontid Pachygenelus (Therapsida: Cynodontia)

Tritheledontids are advanced cynodonts that are considered the sister group of Mammalia. To date the postcranial skeleton has remained largely unknown, so that cladistic analyses are based on cranial characters only. This paper describes a specimen of the tritheledontid Pachygenelus which has most of the skull and vertebral column, a complete shoulder girdle, and most of the forelimb. The girdle and limb are closely comparable to those of Massetognathusand Eozostrodon, and unlike these elements in tritylodontids, which are more derived for fossorial specialisations.The Council's Research Committee, University of the Witwatersrand; National Research Foundation (NRF); Palaeo-Anthropology Scientific Trust (PAST

A new procolophonid (Parareptilia) from the Lystrosaurus Assemblage Zone, Beaufort Group, South Africa

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.THE COUNCIL’S RESEARCH COMMITTEE, UNIVERSITY OF THE WITWATERSRAND; NATIONAL RESEARCH FOUNDATION (NRF

Morphology and growth of the Massospondylus braincase (Dinosauria Prosauropoda)

The almost complete disarticulated braincase of a young Massospondylus, and the partial braincase of a very large individual in which the laterosphenoid bones are preserved, are described

Fossil vertebrate studies in Rhodesia: sphenodontid remains from the upper Trias of Rhodesia

NoneSmall sphenodontid rhynchocephalians are known from the upper Trias in Britain (Robinson, 1973). This paper records for the first time the presence of sphenodontids of very similar age, size, and morphology from the Upper Trias of Rhodesia.Non

The importance of Karoo fossils in the search for mammal origins.

Main articleIt has long been known that mammals belong to the group Synapsida (more familiar to most in South Africa by the now discredited term Mammal-like Reptiles), a group with a long fossil history, much of which was first established from the Karoo. In palaeontology mammals are traditionally defmed by the possession of a squamosal/dentary jaw joint, as opposed to the quadrate/articular jaw joint of non-mammalian tetrapods. This paper recounts some of the advances in our knowledge of the therapsids (advanced synapsids) over the past 50 years, including the discovery of a sequence offorms leading to those which possess both premammalian and mammalianjaw hinges, transitional forms which thus by defInition qualify as mammals. Briefmention is made of some historical aspects of phylogenetic interpretation, pointing out that some early workers following Darwin, were as aware of the central role of species in phylogenetics as are the disciples of Hennig and Eldredge and Gould. Briefreference is made to the crown group defmition of mammals proposed by Rowe (1988), as it contrasts with the traditional character-based definition. Finally, it is encouraging that modem workers are not only as aware of the problems of distinguishing homology and homoplasy as were earlier workers, but are starting to acknowledge the importance of missing information. In this way, just as the double jaw joint was first predicted and then found, we can actively seek to fill some of the many remaining gaps in our knowledge.Non

The advent of herbivory in certain reptilian lineages during the Triassic

Main articleThe dentitions of several presumed herbivorous Triassic reptiles are described and discussed. Some changes in dentitions with growth suggest that juveniles were insectivorous. The appearance of these forms may have been facilitated by floral changes which took place in the early Triassic.Non

The Triassic reptile Palacrodon browni Broom, synonymy and a new specimen

Palacrodon browni Broom 1906 (=Fremouwsaurus geludens Gow 1992) is a small enigmatic diapsid reptile from the Cynognathus Assemblage Zone of South Africa and Antarctica whose dentition is very similar to that of coeval procolophonids.The Council's Research Committe, University of the Witwatersrand; National Science Foundatio

A note on the postcranial skeleton of Milleretta (Amniota: Parareptilia).

Main articleThis description of a partial postcranial skeleton of a mature individual of Milleretta rubidgei shows that it has very broad (laterally expanded) ribs, and growth of limb bones had ceased. Previously the only described postcranial skeleton was that of a young individual in which the ribs are not as broad and the ends of the limb bones were still formed of cartilage.Non