Taxonomy and biostratigraphy of Cretaceous megaspores from Patagonia, Argentina

VILLAR DE SEOANE, L; ARCHANGELSKY, S.

CRETACEOUS RESEARCH (PRINT)

Elsevier Science Ltd

Lugar: Amsterdam; Año: 2008 p. 354 - 372

0195-6671

Megaspores from the Kachaike and Piedra Clavada formations of Albian and ?Cenomanian age in Santa Cruz Province, Argentina, are describedand illustrated by scanning electron micrographs. These include six new species: Arcellites humilis, A. pentagonalis, A. sp. A, Erlansonisporitesverrucatus, Minerisporites aequatus and Striatriletes areolatus. Striatriletes reticulatus (Zerndt) Sweet and Trileites cf. T. murrayiHarris) Marcinkiewicz are recorded for the first time from Argentina. Another eight species that were previously recorded in Patagonia arealso described based on specimens found in new localities. Comparison with similar megaspore taxa from other palaeofloristic regions suggeststhat the megaspores in these formations are of Albian age (perhaps extending into the Cenomanian), confirming previous data obtained fromother studies of marine and terrestrial fossils from these formations. The botanical affinities of the megaspores with heterosporous lycopsidsIsoetaceae and Selaginellaceae) and water ferns (Marsileaceae and Salviniaceae) suggest that a warm, humid climate and abundant water bodiesprevailed during the Albian in Patagonia. The stratigraphic distribution of all known Early Cretaceous Patagonian megaspores allows recognitionof three separate assemblages, M1eM3, each characterized by several exclusive taxa. M1 spans the BerriasianeBarremian, M2 is Aptian, andM3 is Albiane?Cenomanian. 2007 Published by Elsevier Ltd.