IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The early biogeographic history of tetrapods in the Southern Hemisphere: the spatial and temporal distribution of Permian-Triassic basal tetrapods in Gondwana
Autor/es:
MARSICANO, CLAUDIA
Lugar:
Roca
Reunión:
Simposio; Simposio Istmos y rutas marítimas: las conexiones biogeográficas en el Hemisferio Sur a través del tiempo; 2011
Resumen:
Temnospondyls are one of the most species-rich and widespread of all groups of early tetrapods. Following their first appearance in the Mississippian of Europe, they rapidly diversified in the Northern Hemisphere during the Permian. In contrast, the history of the early diversification of the group in the Southern Hemisphere is fairly patchy. The earliest record of temnospondyls include Pennsylvanian footprints from northern Chile followed by a gap of more than 50 My that separates it from Lopingian (late Permian) records known from southern Africa (Karoo Basin), Brazil (Paraná and Parnaíba basins), and central India. They include representatives of Laurasian groups (e.g. Archegosauridae) but also endemic Gondwanan groups, as rhinesuchids. By the end of the Permian, temnospondyls are widespread in the Southern Hemisphere but not as diversified as in the northern continents. The only exception to this late Paleozoic records are the early Permian temnospondyl remains from western Namibia (Gai-as Formation). Recent work in the area evidenced they were abundant and apparently diversified, just above the Mesosaurus bearing-levels in the area dated as Artinskian. Thus, Namibian temnospondyls represent the earliest body-fossil remains of the group in Gondwana. After the Permian-Triassic boundary, temnospondyls stereospondyls have already a widespread distribution in Pangea that continued until the end of the Triassic, when they nearly disappeared. Recent phylogenetic analysis suggests that this apparent abrupt radiation was an extension of a Late Permian event, which probably took place in western Gondwana, although the fossil record has failed to document thus far.