CAPITOSAURID AMPHIBIANS FROM THE UPPER LUANGWA VALLEY, ZAMBIA

The purpose of this paper is to describe two capitosaur skulls from the Luangwa valley, Zambia. A tentative decision is made assigning the material to Parotosaurus pronus (Howie, 1969). The stratigraphy of the locality in which the material was found and that of the type species is discussed. A possible mechanism for opening the mouth of capitosaurs is put forward, with the qualification of its success depending on the animals being neutrally buoyant.The Witwatersrand University, and a C.S.I.R. postgraduate bursar

Preliminary report on two Triassic dicynodonts from Zambia.

Main articleThe purpose of this communication is to establish the presence of a species of Stahleckeriid, hitherto known only from India, in the Zambian Triassic N'tawere Formation and to establish the new specific name of the Kannemeyeria specimen also recorded from the same locality. The skulls and some post-cranial material of these two dicynodonts were collected by Mr. James Kitching from the Luangwa Valley, Zambia in 1961. The material comes from Locality 16, of the Lower Fossiliferous Horizon in the N'tawere Formation. One large skull has been assigned to genus and species Rechnisaurus cristarhynchus Roy Chowdhury, 1970. The other skull and the postcranial material has been named Kannemeyeria latirostris sp. nov. One other specimen has been described from this locality, Diademodon rhodesiensis (Brink 1963), which marks it as being of near Cynognathus-zone age.Non

Cranial anatomy of the giant Middle Triassic temnospondyl Cherninia megarhina and a review of feeding in mastodonsaurids

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.The Council's Research Committee, University of the Witwatersrand; National Research Foundation (NRF); Palaeo-Anthropology Scientific Trust (PAST)

EVOLUTIONARY TRENDS IN TRIASSIC DICYNODONTIA

Triassic Dicynodontia differ from most of their Permian ancestors in a number of specialisations that reach extremes in the Upper Triassic. These are ( 1) increase in total body size, (2) increase in the relative length of the snout and secondary palate by backward growth of the premaxilla, (3) reduction in the length of the fenestra medio-palatinalis combined with posterior migration out of the choanal depression, (4) shortening and dorsal expansion of the intertemporal region, (5 ) fusion of elements in the front part of the brain-case, (6) posterior migration of the reflected lamina of the mandible, (7) disappearance of the quadrate foramen and the development of a process of the quadrate that extends along the quadrate ramus of the pterygoid. It is thought that the occurrence of the last feature in Dinodontosaurus platygnathw Cox and Jacheleria colorata Bonaparte warrants the transfer of the species platygnathus to the genus Jacheleria and the erection of a new subfamily, Jachelerinae nov. It is concluded that the specialisations of the Triassic forms can be attributed to adaptation to a Dicroidium-dominated flora

A new brachyopid, Batrachosuchus concordi sp. nov. from the Upper Luangwa Valley, Zambia with a redescription of Batrachosuchus browni Broom, 1903

Main articleTwo brachyopid skulls from southern Africa are described: one from the N'tawere Formation, Zambia is assigned to Batrachosuchus concordi sp. nov. and the other, B. browni Broom from the Cynognathus zone of South Africa is used as comparative material after further preparation had been effected on it. Both are assessed in relation to published descriptions of B. watsoni and it is concluded that B. concordi is closest to B. watsoni. The possibility that B. watsoni and B. browni belong to the same species is discounted for the present as there are four distinct differences in their skull morphology. Some poorly preserved and enigmatic bones from immediately behind the occiput of B. concordu are interpreted as limb and girdle elements. Associated with these bones are an axis and an atlas. All three species are at about the same level of organisation and that helps confirm that the Cynognathus zone of South Africa and the N'tawere Formation of Zambia are of approximately the same age and span the Lower-Middle Triassic boundary.Non

Three capitosaurs from the Triassic of South Africa: Parotosuchus africanus (Broom 1909); Kestrosaurus dreyeri Haughton 1925, and Parotosuchus dirus sp. Nov.

Main articleTwo members of the family Capitosauridae are redescribed after further preparation, namely Paratosuchus africanus (Broom 1909) and Kestrasaurus dreyeri Haughton, 1925. New material consisting of a fragmental, lower jaw or a very large parotosaur from the Cynognathus zone of Aliwal North is described, upon which a new species, Parotosuchus dirus, is erected. Paratosuchus africanus (Broom 1909) from the Cynognathus zone of Vaalbank, Albert, Cape Province, is redescribed and figured for the first time. It consists of most of the postorbital regions of the skull associated with part or the left lower jaw which are fairly well preserved and capable of being directly compared with the same parts of other taxa. Thus it is reconfirmed a valid member of the family Capitosauridae. Kestrosaurul dreyeri is re-examined and found to consist of large areas of plaster of Paris in which the original bone has been embedded. The entire skull could be about 5 cm shorter than the original reconstruction. The position and shape of the orbits are not preserved and the reconstructed lateral position found in the specimen is arbitrary. The parietal foramen is also not preserved. The nature of the preserved palate and occipital area indicates that the material probably represents a primitive member of the family Capitosauridae, not only stratrigraphically ( Lystrosaurus zone), but also morphologically. The taxonomic designation established by Welles and Cosgriff (1965) is retained. Kestrosaurus remains an enigma because it also displays certain trematosaurid characters. A partial capitosaurid jaw from the Cynognathus zone of Aliwal North, Cape Province, is also described which when reconstructed represents one of the largest amphibians found in Southern Africa. Comparisons are made with Parotosuchus pronus (Howie 1970) and Parotosuchus megarhinus (Chernin and Cosgriff 1975), which share a few similar characteristics. It is suggested that the amphibian represented by this jaw may be ancestral to both P. pronus and P. megarhinus. Based on substantial morphological differences in the symphysial and articular regions between this jaw and those of the above-mentioned parotosaurs, it is hereby proposed to erect a new species, Paratosuchus dirus (dirus = Latin: fearful), for this material.Non

Allometric growth in the Diademodontinae (Reptilia; Therapsida); a preliminary report

Main articleThe hypothesis that many, if not all, of the South African and Zambian specimens, which have been regarded as different diademodontine genera and species, actually consitute a taxonomically homogeneous, ontogenetic growth series is tested. The principles of allometric growth were applied to this sample of fossils, which varied considerably in size and shape. The approach which was followed was exclusively morphometric. The results indicate that these specimens do represent various ontogenetic stages of a growth series of only a single species of Diademodon Seeley.Non

The skeleton of the Triassic anomodont Kannemeyeria wilsoni Broom

The general structure of the post-cranial skeleton of many Triassic anomodonts is now well known, but in Africa that of the stratigraphically important Lower Triassic (? Scythian) genus Kannemeyeria is known only from dissociated elements. A brief description is given for the first time of an almost complete skeleton ascribed to this genus. The environment of deposition is described briefly. The locality of the type species of the genus is also noted .CSIR; University of the Witwatersran

A NEW TRIASSIC VERTEBRATE FAUNA FROM SOUTH WEST AFRICA

A new fauna of mammal-like reptiles is described from a continental sequence of sediments in South West Africa hitherto known as the Etjo Beds. These include representatives of the Anomodontia (two new forms and one known from the Karroo basin), Bauriamorpha, (one specimen comparable with a known form), Cynodontia (one new form and two known from the Karroo basin) and one small eriopoid amphibian. On the basis of this faunal assemblage it can be shown that there is a disconformity between the upper Plateau Sandstone Formation containing traces of Dinosaurs of possible Carnian-Norian age and a lower Omingonde Mudstone Formation with this new fauna, of essentially Upper Beaufort (Scythian/Anisian) age. The two formations are distinguished on lithological grounds. The Triassic sequence in the neighbouring Doros area is thought to be equivalent to the Plateau Sandstone Formation