Browsing Volume 25 1984 by Title
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ItemBiostratigraphy and paleontology of some conchostracan-bearing beds in southern Africa(Bernard Price Institute for Palaeontological Research, 1984) Tasch, PaulThe present field and laboratory study was undertaken in conjunction with a monograph being prepared on Gondwana estheriids. Detailed biostratigraphic reports are lacking on the southern African conchostracan-bearing beds. The available paleontological treatment ranges from mere mentions of certain fossils being present to spare systematics. During the summer of 1979 a limited exploration program was undertaken at localities in the Clarens Formation (Cave Sandstone) outcrop belt where conchostracans had been reported (Stockley 1947, Haughton 1924, and especially Ellenberger et al. 1964). In particular, sites at Siberia and Barkly Pass (both in the Republic of South Africa) and at Thabaneng and Mofoka's Store (both in Lesotho) were found to yield excellent new biostratigraphic and paleontological data. The exploration covered some 1500 square miles (2400km2 of the Clarens Formation (Cave Sandstone) outcrop belt (Text fig. 1). Conchostracan-bearing Cave Sandstone sites noted by Paul Ellenberger (1970) at Leloaleng, Masitisi, Mohaleshoek, Brakfontein and elsewhere were systematically explored. Because of the lack of precise locality data enabling one to pinpoint the fossiliferous bed(s) even an intensive search did not uncover the reported fossiliferous beds. Exploration of one of Ellenberger's localities at Wonderkop (RSA) was abandoned after a preliminary search due to time limitations. This site may yet prove productive. ItemThe fossil content of the Upper Triassic Molteno Formation, South Africa(Bernard Price Institute for Palaeontological Research, 1984) Anderson, John M.; Anderson, Heidi M.;The present paper is essentially drawn, with a few additions (the insects in particular) and changes, from the section on the Molteno Formation in the book Prodromus of South African megafloras: Devonian to L. Cretaceous currently in press (Anderson and Anderson 1984). The repetition is justified by the nature and scope of this Haughton Memorial Volume- an attempt to bring together a series of papers giving a general overview of the 'Stormberg Series' (Molteno to Drakensberg formations). We are in the process of preparing a series of volumes on the palaeoflora of the Molteno Formation. These are based primarily on our own collections begun in 1967 and now amounting to 15 500 catalogued slabs from 74 assemblages. The first volume has been published (Anderson and Anderson 1983a) and provides an interim synthesis of the megaflora to species level as well as a detailed taxonomic account of Dicroidium, the dominant most diverse element. For further detail and clarification of aspects of the paper presented here the above mentioned volumes should be consulted. ItemFossils from the Elliot and Clarens Formations (Karoo sequence) of the Northeastern Cape, Orange Free State and Lesotho, and a suggested biozonation based on tetrapods(Bernard Price Institute for Palaeontological Research, 1984) Kitching, James W.; Raath, Michael A.Recent intensive collecting from the Elliot Formation and lower part of the Clarens Formation of the Orange Free State is reported and a broad description is given of the general lithology of the beds in this area. Productive localities in the main Karoo basin (northeastern Cape Province, Lesotho, Orange Free State} are listed with a summary of the tetrapods recovered from each. A preliminary biozonation of these strata is proposed based on the vertical ranges of the prosauropod saurischian genera Euskelosaurus and Massospondylus. Attention is drawn to a palaeontologically rich horizon within the Massospondylus Range Zone which is designated the Tritylodon Acme-zone on the basis of the abundance in it of the advan- ced cynodont Tritylodon cf. longaevus. It is concluded that previous taxonomic work on the tetrapod fauna of these strata has resulted in an erroneous impression of faunal diversity. ItemIn Memoriam: Sidney Henry Haughton, BA, DSc, Hon LLD, Hon DSc, FRS, FGS, Hon FRSSAfr (1888-1982)(Bernard Price Institute for Palaeontological Research, 1984) Raath, Michael A. ItemLate Triassic traversodont cynodonts from Nova Scotia and southern Africa(Bernard Price Institute for Palaeontological Research, 1984) Hopson, James A.The first gomphodont cynodont from North America is described from the Upper Triassic Wolfville Formation, Fundy Group, Newark Supergroup, of Burntcoat, Minas Basin, Nova Scotia, Canada. Known material consists of a large mandible, edentulous but for two incisors, a probably associated canine, and two small dentaries; an isolated multicusped tooth may belong to this species. This gomphodont closely resembles the large traversodont Scalenodontoides macrodontes from the lower Elliot Formation (= Red Beds) of Lesotho; it is provisionally placed in this genus but is a distinct species, ?Scaleno- dontoides plemmyridon sp. nov. It differs from S. macrodontes primarily in its more massive symphyseal region and much larger mental foramen from which a prominent groove extends posterodorsally. The large, posteriorly-located mental foramen is believed to be a well-developed oral vestibule and cheek. The isolated tooth, provisionally interpreted as a traversodont lower postcanine, is anteroposteriorly compressed, with a high anterior blade formed by three transversely-aligned cusps and a short heel; it does not resemble postcanines of S. macrodontes and so reference to ?S. plemmyridon is questionable. Scalenodontoides is the sister genus of Exaeretodon from the Late Triassic of Argentina, Brazil, and India; they are allied on the basis of: upper incisors reduced from 4 to 3, all incisors greatly enlarged, and internarial bar incomplete. These resemblances to tritylodontids are convergent. Scalenodontoides and Exaeretodon share with Gomphodontosuchus the enlargement of the anterolabial cusp of the lower postcanines and posterior inclination of the anterolingual cusp. The Wolfville and basal Elliot faunas are considered to be Late Carnian or Carno-Norian in age. Faunas containing Exaeretodon are older Carnian, though the Santa Maria Formation of Brazil may be Late Ladinian. ItemA new protosuchian crocodile from the Upper Triassic Elliot Formation of South Africa(Bernard Price Institute for Palaeontological Research, 1984) Busbey, Arthur B. III; Gow, ChrisA new protosuchian crocodilian, Baroqueosuchus haughtoni from the Upper Triassic or Lower Jurassic Elliot Formation of the Orange Free State is the most primitive protosuchian crocodilian known. There are no contacts between the quadrate and opisthotic or below the crania-quadrate canal, the internal carotid arteries were not enclosed in separate foramina and the basicranium was flat, with the basisphenoid being broadly exposed on the base of the skull. The basic diagnosis of the Order Crocodilia is discussed and a new diagnosis is offered based upon cranial anatomy. ItemPalaeogeographic implications of braid bar deposition in the Triassic Molteno formation of the eastern Karoo Basin, South Africa(Bernard Price Institute for Palaeontological Research, 1984) Turner, Brian R.The Triassic Molteno Formation in the main Karoo Basin, South Africa, forms a northerly thinning intracratonic clastic wedge deposited by sandy braided rivers of South Saskatchewan type. Deposition of the sandy facies was dominated by channel floor mega-ripples producing trough cross-bedded cosets; transverse bars, represented by solitary, large-scale planar sets are not significant. Departures from this regional pattern of sandstone deposition occur along the northern distal margin of the Molteno basin around Bethlehem in the Orange Free State. Here thickness trends and clast size delineate a deep channel system interpreted as the main braided exit channel from the basin. Because of its depth and constriction by local height differentials the competency and capacity of the flow were able to reproduce features more typical of proximal rather than distal depositional settings. The sandy facies is dominated by fine gravel with lesser amounts of coarse sand. Gravel occurs as longitudinal bars some of which contain low angle foreset stratification whose orientation is consistent with lateral growth and marginal riffle migration. The scale of the bars and simple deposi- tional form imply that they may have been larger than modern equivalents and the flows deeper. The coarse sand occurs mainly as falling water stage features associated with the gravel bars. Shallow channel-fills, bar edge sand wedges, bar top sheet sands and thicker channel sands have been recognised and compared with similar features in modern and ancient braided stream sediments. When traced to the southeast the deep channel sediments contain few longitudinal gravel bars and more transverse bars; the vertical sequence from longitudinal to transverse bars at this locality points to the increasing distality of the depositional site through time. ItemPostcranial remains of Fabrosauridae (Reptilia: Ornithischia) from the Stormberg of southern Africa(Bernard Price Institute for Palaeontological Research, 1984) Santa Luca, A. P.The postcranial skeletons of three fabrosaurids from the upper Elliot Formation "Red Beds" of the Stormberg Group in southern Africa are described. The material demonstrates details of fabrosaurid anatomy previously unknown, particularly a short, deep prepubic process which is undoubtedly primitive for the Ornithischia. Besides the short prepubis, fabrosaurids are characterized by 1) a reduced manus; 2) an ilium having a lateral extension of the supra-acetabular margin and a deep nearly vertical brevis shelf; and 3) an elongated hindlimb. Postcranial morphology excludes the fabrosaurids from the ancestry of the contemporaneous heterodontosaurids. Neither can the fabrosaurids be considered ancestral to the 'juvenile scelidosaurid' (BMNH R6704) as has been suggested. On the contrary, the 'scelidosaurid' is more primitive in structure than fabrosaurids. The assignment of Nanosaurus agilis Marsh to the Fabrosauridae is not substantiated after morphological comparisons between the postcranial material of both. The taxonomic status of Scutellosaurus lawleri is regarded as uncertain. The fabrosaurids are more similar to the Morrison Formation camptosaurids, than to Hypsilophodon. Finally, it is argued that ornithopods were not a basal stock for the phylogenesis of non-ornithopods but represent an independent radiation comparable to the other ornithischian suborders. The fabrosaurids were an early development of the ornithopod radiation itself. ItemA reassessment of Vulcanodon karibaensis Raath (Dinosauria:Saurischia) and the origin of the Sauropoda(Bernard Price Institute for Palaeontological Research, 1984) Cooper, Michael R.Vulcanadon karibaensis Raath is redescribed and figured in detail. It forms the basis of the new sauropod family Vulcanodontidae, to which the Indian Barapasaurus is also provisionally referred. The retention of numerous symplesiomorphies with the Prosauropoda leaves little doubt as to its ancestry. It is considered a primitive sauropod on account of its large size, columnar limbs, pelvic structure, reduced cnemial crest to the tibia, lack of distal tarsals, the length of its forelimbs and its quadrupedal gait. The post-cranial anatomy of Vulcanodon is sufficiently generalized for the Vulcanodontidae to have formed the ancestral stock of both the Camarasauridae and Diplodocidae. ItemA review of the reptile and amphibian assemblages from the Stormberg of southern Africa, with special emphasis on the footprints and the age of the Stormberg(Bernard Price Institute for Palaeontological Research, 1984) Olsen, Paul E.; Galton, Peter M.The Molteno, Elliot, and Clarens formations comprise the continental Stormberg Group of the Karoo Basin of South Africa and Lesotho. The Molteno Formation contains a well preserved macro- and microfloral assemblage but apparently no vertebrates; the Elliot and Clarens formations contain abundant vertebrates but virtually no floral remains. The vertebrate taxa represented by skeletal remains are listed and divided into two assemblages - the lower Stormberg (lower Elliot) and upper Stormberg (upper Elliot and Clarens) assemblages. The abundant, diagnosable footprint taxa are revised and their names reduced to eight genera. These ichnotaxa also fall into two biostratigraphic zones that parallel the skeletal assemblages. Comparison of the faunal assemblages with those of the European type section strongly suggests that the lower Stormberg assemblage is Late Triassic (Carnian- Norian) in age while the upper Stormberg assemblage is Early Jurassic (Hettangian-Pliens- bachian) in age. Comparisons with other continental assemblages from other areas suggest that the upper Stormberg (upper Elliot and Clarens formations) assemblage broadly correlates with the upper Newark Supergroup of eastern North America, the Glen Canyon of the southwestern United States, and the lower Lufeng Series of China- all thought to be of Early Jurassic age on the basis of floral and/or radiometric evidence. Based on these correlations, previously published paleobiogeographic maps are revised; these show a shift from Late Triassic floral and faunal provinciality to Early Jurassic homogeneity. This shift was synchronous with a widening of the equatorial arid zone. ItemA review of the Stormberg Group and Drakensberg volcanics in southern Africa(Bernard Price Institute for Palaeontological Research, 1984) Visser, J. N. J.The Molteno Sandstone, Red Beds and Cave Sandstone comprising the Stormberg Group (siliciclastics) in South Africa and their correlatives, based on lithology, depositio- nal environments and tectonic cycles, in Zimbabwe, Botswana and Namibia are described. The Drakensberg Volcanics with radiometric ages of 114 My to 194 My cap the sedimen- tary sequence. A major unconformity separates the Stormberg sedimentary rocks from the lower Karoo strata. Four Late Triassic depositional basins which were tectonically controlled are recognised. The Molteno Sandstone and Red Beds filling these basins represent braided and meandering stream deposits respectively. The Cave Sandstone covering the fluvial deposits formed as desert sand sheets reworked by westerly winds. Deposition was ended by the outpouring of the Drakensberg Volcanics.