MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
The southernmost record of tropical pollen grains in the Cretaceous of Patagonia, southern Argentina.
Autor/es:
BARREDA, V.; ARCHANGELSKY, S.
Revista:
CRETACEOUS RESEARCH (PRINT)
Editorial:
Elsevier
Referencias:
Año: 2006 vol. 27 p. 778 - 778
ISSN:
0195-6671
Resumen:
Pollen grains characteristic of tropical Northern Gondwana (Schrankipollis, Brenneripollis and Pennipollis peroreticulatus) have been recorded from the Cretaceous of Patagonia. They were recovered from the Late AlbianeCenomanian Kachaike Formation in Santa Cruz Province, southern Argentina. The palynological assemblages are dominated by gymnosperm pollen and bryophyte-pteridophyte spores, whereas angiospermsare poorly represented. The angiospermoid type Schrankipollis has not been reported previously from Argentina, and a new species S. kachaikensis is described. Two species of Brenneripollis (of uncertain affinity) and Pennipollis peroreticulatus (related to the Alismatales) are also reported. The first appearances of Pennipollis peroreticulatus are clearly diachronous from north to south, ranging from the Barremian in tropical regions to the ConiacianeSantonian in Antarctica. S. kachaikensis and P. peroreticulatus show restricted stratigraphic distributions through the Kachaike Formation and may be stratigraphically useful markers. A tetrad of Walkeripollis (related to modern Winteraceae) is also recognized. This is the oldest record of Winteraceae in the southern temperate region where the family lives today. Evidence for migration of Winteraceae from tropical Gondwana to Antarctica and Australia throughout South America, is provided by this new finding. The presence oftropical elements in the austral margin of South America gives support to previous studies on the expansion of warm temperatures towards high latitudes during the mid Cretaceous.