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Wyszukujesz frazę "Karoo" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
New features of the snout and orbit of a therocephalian therapsid from South Africa
Autorzy:
Sigurdsen, T
Powiązania:
https://bibliotekanauki.pl/articles/21325.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Akidnognathidae
dentition
Karoo basin
Therocephalia
therocephalian therapsid
South Africa
tooth
Therapsida
Synapsida
paleontology
Opis:
I describe the anterior part of the externally poorly preserved skull of a therocephalian from the Karoo Basin in South Africa, using the method of serial grinding. The skull is incomplete, and its estimated length in life is 130 mm. The skull can be assigned to the Akidnognathidae with some confidence. The stratigraphic age of the specimen and its locality are not known, but the surrounding sediment suggests that it may be from the Upper Permian Dicynodon Assemblage Zone. It has five or six postcanine teeth, and a poorly developed crista choanalis. The sinuses and canals of the snout are recognized, and it is believed that the sinus positioned posteriorly in the snout (posterior maxillary sinus) is homologous with the maxillary sinus of anomodonts and cynodonts. It also shows similarities to the infraorbital canal of early mammals, such as Morganucodon. An anteriorly positioned sinus (anterior maxillary sinus), situated directly behind the canine root, is homologized with the maxillary sinus of gorgonopsians. In addition, I identify the previously undescribed canal (designated anterior maxillary canal), leading from the anterior maxillary sinus antero−dorsally. No evidence for maxilloturbinals was found in contrast to the condition known in the primitive therocephalian Glanosuchus
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nycteroleter affinities of a Permian parareptile from the South African Karoo Basin
Autorzy:
Cisneros, J C
Tsuji, L.A.
Powiązania:
https://bibliotekanauki.pl/articles/23121.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Karoo Basin
paleontology
Permian
parareptile
Tapinocephalus
South Africa
Middle Permian
Opis:
The Middle Permian Tapinocephalus Assemblage Zone in South Africa has produced a rich record of tetrapods dominated by dinocephalian therapsids and pareiasaurid parareptiles. In this study we reassess the affinities of a specimen from this horizon previously identified as a procolophonoid and provide evidence that it is instead referable to a nycteroleter parareptile, an identification that is more compatible with the age of this fossil. Accordingly, this specimen represents the first record of a nycteroleter in Gondwana.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 1; 165-169
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of distribution and geometry of lithological complexes of the Ecca Group (the Karoo Supergroup) in SW Botswana
Autorzy:
Wendorff, M.
Radwański, L.
Papiernik, B.
Powiązania:
https://bibliotekanauki.pl/articles/184306.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Karoo Supergroup
Ecca Group
deltaic sedimentation
modelling
SW Botswana
Opis:
The Ecca Group, a subdivision of the Karoo Supergroup (Upper Carboniferous - Lower Jurassic) in SW Botswana is a sequence deposited as marine deltaic bodies considered to have been supplied from a cratonic source elevated north of the basin. The Karoo strata in this region are covered unconformably by sands of the Kalahari Beds (Upper Cretaceous - Recent). Therefore the bedrock outcrops are extremely rare, limited in size and a low number of boreholes drilled in this vast area (ca. 340 x 540 km) provide the only insights into the succession of the Karoo Supergroup. Very long distances between individual boreholes make correlation, interpolation between localities and interpretations of geometry of lithological bodies that would provide clues supporting basin analysis by traditional means problematic. To achieve the first approximation of the space-time relations between lithologically complex Ecca Group lithofacies associations modelling of these sediments using Petrel software was performed. These relations in turn suggest evolutionary trends of the basin during deposition of the Ecca Group strata. The model suggests two main zones of supply indicated by two distinctly different patterns of deltaic lithofacies associations, and their evolution controlled by post-Dwyka palaeotopography and its subsequent modifications by local subsidence in the centre of the depository. Initially rapid southward progradation of relatively fine-grained delta body located in the west of the area was followed by subsidence-induced aggradation interrupted by stages of abandonment and marine transgression. Such variations, emphasised by the presence of sandy clinoforms of the delta lobes separated by basinal "fines", imply significant interplay between rates of supply and subsidence. On the other hand, the delta formed in the east contains relatively high proportion of coarse-grained sandstone facies overlying prodelta fines as laterally extensive tabular body formed most probably by lateral migration of distributary channels and delta-front mouthbars, and devoid of abandonment stages. Proximal litofacies of the "western delta" fill the subsiding depocentre and grade distally into synchronously deposited prodelta fines towards the south. By contrast, distal fine-grained prodelta facies fill basin depocentre in the eastern area and are overlain by proximal facies of the "eastern delta".
Źródło:
Geology, Geophysics and Environment; 2013, 39, 1; 55-70
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dinosaur behaviour in an Early Jurassic palaeoecosystem – uppermost Elliot Formation, Ha Nohana, Lesotho
Autorzy:
Rampersadh, A.
Bordy, E. M.
Sciscio, L.
Abrahams, M.
Powiązania:
https://bibliotekanauki.pl/articles/191599.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
vertebrate ichnology
tridactyl
tetradactyl
climate change
southern Gondwana
Karoo
upper
Elliot Formation
Opis:
The Ha Nohana palaeosurface in southern Lesotho preserves tridactyl and tetradactyl tracks and trackways attributable to Early Jurassic bipedal, theropod-like dinosaurs. Complementary sedimentological and ichnological observations along the palaeosurface and in the strata below and above it allow detailed interpretations of climatically driven changes in this southern Gondwana palaeoecosystem. Sedimentological evidence suggests trackmaking under a semi-arid climate with heavy storms and episodic flash flooding that induced ephemeral, unconfined sheetwashes. The palaeosurface is overlain by rhythmically bedded, organic-matter rich mudstones that formed in a deep, stratified lake indicative of a longer and wetter period in the history of the site. The unique morphological details of the Ha Nohana tracks help refine the properties of the substrate during track making, the ichnotaxonomic affinities of the footprints and the interpretation of the foot movement relative to the substrate. Two footprint morphotypes, ~ 300 m apart, are defined on the palaeosurface. Tracks of morphotype I are tridactyl, shallow, contain digital pad impressions and were impressed on a firm, sand rippled substrate that underwent desiccation. Conversely, tracks of morphotype II are tetradactyl, deep, and have an elongated posterior region. These tracks are preserved on the surface of a massive sandstone and are associated with soft sediment collapse structures related to the animal’s foot sinking into the water-saturated, malleable sediment layer. Morphotype II tracks show that as the animal waded across the substrate, the liquefied sediment lost its cohesive strength and could only partially support the weight of the animal. In so doing, the animal’s foot sunk deep enough into the sediment such that the impression of the metatarsal and digit I (hallux) are now visible. Thus, the palaeosurface was walked on by small-to-medium sized theropods that traversed over ripple marks in firmer moist sand, as well as a larger theropod that tottered through water-logged sand.
Źródło:
Annales Societatis Geologorum Poloniae; 2018, 88, 2; 163-179
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Large tridactyl dinosaur tracks from the Early Jurassic of southern Gondwana : uppermost Elliot Formation, Upper Moyeni, Lesotho
Autorzy:
Abrahams, Miengah
Sciscio, Lara
Reid, Mhairi
Haupt, T’nielle
Bordy, Emese M.
Powiązania:
https://bibliotekanauki.pl/articles/1836362.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
vertebrate ichnology
tridactyl
large theropods
southern Gondwana
Karoo
upper Elliot Formation
Opis:
A new ichnosite in southwest Lesotho (Upper Moyeni; Quthing District) is located within the uppermost part of the highly fossiliferous Elliot Formation, ~35 m below the conformably overlying Clarens Formation and ~65 m above the world-renowned Lower Moyeni ichnosite. While the Lower Moyeni site preserves diverse Early Jurassic ichnofossils, the ichnites at the Upper Moyeni comprise one vertebrate burrow and ~50 tridactyl tracks with footprint lengths between 15 and 51 cm. Many of the tracks preserve digital pad impressions, claw marks and displacement rims, all related to substrate conditions. The morphometric parameters of the Upper Moyeni tracks are consistent with Grallator, Eubrontes and Kayentapus. Several larger tracks with footprint lengths > 40 cm are Kayentapus-like and Eubrontes-like, and are comparable to previously described very large theropods tracks with lengths > 50 cm from the uppermost Elliot and Clarens formations. On the basis of sedimentological and ichnological evidence, the Upper Moyeni ichnofossils were formed in a palaeolandscape with small rivers and shallow lakes by burrowing tetrapods and a variety of bipedal dinosaurs (theropods), some of which were up to 7–8 m in body length. The Upper Moyeni tracks, together with the other very large tracks from coeval locations in southern Africa, collectively highlight the tendency towards increasing diversity in size of tridactyl tracks and by extension theropod trackmaker body size body size, which runs in tandem with the increasing diversity of non-sauropod, sauropodomorph body fossils in the Sinemurian-Pliensbachian of southern Gondwana.
Źródło:
Annales Societatis Geologorum Poloniae; 2020, 90, 1; 1-26
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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