Las ostras del límite Cretácico-Paleógeno de la cuenca Neuquina (Argentina). Su importancia bioestratigráfica y paleobiogeográfica

CASADIO, SILVIO

AMEGHINIANA

Asociación Paleontológica Argentina

Lugar: Buenos Aires; Año: 1998 vol. 35 p. 449 - 471

0002-7014

Ten species belonging to seven genera of the ostreoidea are recognized, as the result of a taxonomic revision of the oysters from the Cretaceous-Paleogene in the Neuquen Basin, west-central Argentina. All of them were collected from the Maastrichtian Jagüel Formation and the Roca Formation dated as Maastrichtian-Danian. Four taxa, Amphidonte mendozana (Ihering), Ambigostrea clarae (Ihering), Gyrostrea lingua (Camacho), and Pycnodonte (Phygraea) vesicularis (Lamarck) are Maastrichtian in age. Pycnodonte (Phygraea) burckhardti (Böhm) and Gryphaeostrea callophylla (Ihering) have been recorded from outcrops of the lower part of the Roca Formation (early Danian). Ostrea neuquena Ihering occurs in Danian limestones of the middle part of Roca Formation. Pycnodonte (Phygraea) sarmientoi n. sp. and Cubitostrea ameghinoi (Ihering) are present at the late Danian. Ostrea wilckensi Ihering is recorded from beds ranging from Maastrichtian to Danian in age. Comparison of the fauna with Cretaceous and Paleogene faunas in southern Patagonia and Antarctica indicates that the Neuquen fauna was influenced by dispersal from lower latitude, Tethyan sources in marked contrast to the high latitude, Pacific affinities of the faunas from southern Patagonia.