Browsing Volume 22 1979 by Title
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ItemAn articulated skeleton of a small individual of Diademodon (Therapsida; Cynodontia)(Bernard Price Institute for Palaeontological Research, 1979) Gow, C. E.; Grine, F. E.;This paper records a nearly complete, articulated skeleton of Diademodan in undoubted association with a skull of that animal. Previously, only portions of postcranial skeleton have been found in association with cranial remains of this genus. The skeleton is that of a relatively small (ontogenetically young) individual. Skeletal proportions are tabulated, rib and vertebral differentiation is described and discussed. Diademodon is shown to have had a long tail. ItemEvidence for salt glands in the Triassic reptile Diademodon (Therapsida; Cynodontia)(Bernard Price Institute for Palaeontological Research, 1979) Grine, F. E.; Mitchell, D.; Gow, C. E.; Kitching, J. W.; Turner, B. R.;Fossilised skulls of Diademodon exhibit rostral depressions which may have housed salt glands. The possible functions of salt glands in this advanced cynodont are examined. Diademodon appears to have been more reptilian than mammalian in its general physiological organisation. ItemA new species of the Rhytidosteidae from the Lystrosaurus zone and a review of the Rhytidosteoidea(Bernard Price Institute for Palaeontological Research, 1979) Cosgriff, John W.; Zawiskie, John M.;Pneumatostega potamia, a new rhytidosteid temnospondyl from the Lystrosaurus Zone, is described and compared with the other species of the family. Its evolutionary relationships and adaptive morphology are considered. The closest affinity is with the species of Deltasaurus from the Lower Triassic of Australia, the next closest with the species of Peltostega from the Lower Triassic of Spitsbergen and the most distant with Rhytidosteus capensis, a Karoo species which is probably also from the Lystrosaurus Zone. As with other species of Rhytidosteidae, for which both taphonomic and adaptive morphologic evidence is available, P. potamia was, apparently, a fluviatile, subsurface, piscivorous temnospondyl regarding its primary and preferred habitat. Proceeding from information contributed by the new species, the taxonomic structure of the Rhytidosteoidea is reorganised and expanded and new diagnoses are provided for both this superfamily and its contained families. The family Rhytidosteidae now includes Deltasaurus kimberleyensis, D. pustulatus, Peltostega erici, P. wimani, Pneumatostega potamia and Rhytidosteus capensis. A new family, Indobrachyopidae, is created to include Derwentia warreni (removed from the Rhytidosteidae), Indobrachyops panchetensis, Mahavisaurus dentatus, Mahavisaurus (Lyrosaurus) australis and Rewana quadricuneata. Laidleria gracilis is removed from the Rhytidosteoidea. Latiscopus disjunctus and Almasaurus habbazi possess some features in common with members of the superfamily but are too distinct in most features to be considered rhytidosteoids. Taxonomic distances among the rhytidosteids and indobrachyopids are established by a computer program. A phylogeny of the superfamily is constructed and this is consonant with the stratigraphic and geographic occurrences of the species. A southern origin for the superfamily with a generally northward dispersal is proposed. ItemPreliminary report on a clutch of six dinosaurian eggs from the upper Triassic Elliot Formation, Northern Orange Free State(Bernard Price Institute for Palaeontological Research, 1979) Kitching, J. W.;A clutch of six dinosaurian eggs, containing foetal skeletons of as yet uncertain taxonomic affinity, from the Elliot Formation (Red Bed Stage), northern Orange Free State, seems to be the first record of fossil eggs of Upper Triassic age. As preserved the eggs have a long axis of 65 mm, with a short axis of approximately 55 mm. The egg “shell” is exceptionally thin; fragments removed from one of the specimens have an estimated thickness of 0,5 mm. Additional preparation work is at present being undertaken on a reasonably well-preserved skull in one of the eggs and a more detailed description of the specimen and possible parentage will appear at a later date.