Artículo
First Lower Jurassic vertebrate burrow from southern Africa (upper Elliot Formation, Karoo Basin, South Africa)
Fecha de publicación:
02/2017
Editorial:
Elsevier Science
Revista:
Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN:
0031-0182
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Vertebrate burrows are common ichnofossils in the Permo-Triassic of the main Karoo Basin in South Africa. They are generally attributable to one of several lineages of therapsid, including the derived clade known as cynodonts. Despite the presence of cynodont species in the Upper Triassic and Lower Jurassic of the Karoo Supergroup, vertebrate burrows have never been reported from this part of the succession. Recent fieldwork recovered a semi-elliptical burrow cast in the Lower Jurassic upper Elliot Formation (Stormberg Group) on the farm Edelweiss 698 (Free State). The horizontal and vertical diameters of the burrow cast are ~ 18 and ~ 7 cm, respectively. This semi-horizontal, straight to slightly sinuous tunnel is ~ 50 cm long with a ramp angle of < 5°. The tunnel lacks branching, terminal chambers, and associated fossil bones. The burrow cast consists of medium, massive sandstone and very rare, faint, horizontal to slightly inclined lamination. The burrow cast is hosted in fine-grained, palaeo-pedogenically altered, crevasse splay sandstone that is 10–20 cm thick and is under- and overlain by a massive, red, bioturbated floodplain mudstone unit with large-scale (> 20 cm deep) desiccation cracks, invertebrate trace fossils, calcareous rhizoconcretions, and spherical-to-elongated carbonate nodules. These and other associated sedimentary features provide evidence for a semi-arid, fluvio-lacustrine palaeoenvironment during the burrowing activity. Based on comparisons to fossil and modern burrows, this burrow cast is interpreted as a vertebrate burrow, and is the first record of vertebrate fossorial activity within the Lower Jurassic of southern Africa. The ancient burrow architect has yet to be positively identified. However, given the size and morphology of the burrow and the occurrence of similar sized fossil cynodont therapsids that inhabited the main Karoo Basin in the earliest Jurassic, the potential burrow-maker may be tentatively linked to the Cynodontia (e.g., Pachygenelus - an advanced tritheledontid).
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - NOA SUR)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - NOA SUR
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - NOA SUR
Citación
Bordy, E.M.; Sciscio, L.; Abdala, Nestor Fernando; McPhee, B.W.; Choiniere, J.N.; First Lower Jurassic vertebrate burrow from southern Africa (upper Elliot Formation, Karoo Basin, South Africa); Elsevier Science; Palaeogeography, Palaeoclimatology, Palaeoecology; 468; 2-2017; 362-372
Compartir
Altmétricas