Taxonomy, facies relationships and plaeobiology of bakevelliid bivalves from the Lower Cretaceous of the Neuquén Basin

LAZO, D.G.

CRETACEOUS RESEARCH (PRINT)

Elsevier

Lugar: Cornwall; Año: 2003 vol. 24 p. 765 - 788

0195-6671

Cretaceous bakevelliids in Argentina are restricted to the Lower Cretaceous. They are recorded in shallow marine deposits in two Mesozoic basins located in the Andes foothills in Patagonia. In the Austral Basin (44(–55(S) there is only one genus, Gervillella, represented by a single specimen from the Barremian. In the Neuque´n Basin (30(–40(S) two genera, Gervillaria and Gervillella, occur, ranging from the Berriasian to the Lower Barremian. In the Pilmatue´ Member of the Agrio Formation two species are identified: Gervillaria alatior (Imlay) and Gervillella aviculoides (J. Sowerby). The former is also recorded in Mexico while the latter is more widespread, occurring in Europe, Asia, and Africa. In the Bajada del Agrio section they come from eight tabular shell beds located near and on top of shallowing-upwards cycles. They were abundant only in four of these levels. These shell beds are interpreted as having been deposited in the mid-ramp (middle of cycles), and upper mid-ramp (top of cycles). A functional analysisof shells revealed two life habits: epibyssate and endobyssate.