Abstract

GUERRERO-SANCHEZ, Miguel  and  QUIROZ-BARROSO, Sara A.. Guadalupian bivalva (middle Permian) of the Olinalá Formation, Guerrero, Mexico. Bol. Soc. Geol. Mex [online]. 2013, vol.65, n.3, pp.533-551. ISSN 1405-3322.

The study material comes from rocks that outcrop northeast of the town Olinalá, in Guerrero state. The marine facies of Olinalá Formation are included in light to dark gray shale with fossils of brachiopods, gastropods, bivalves, cephalopods, crinoids stems, wood and other plant remains, locally included in concretions. The diversity of bivalves is represented by the infaunal species Nuculavus levatiformis, Palaeoneilo mcchesneyana, Edmondia phosphatica, and ?Cardiomorpha sp.; the epifaunal species, adhered to different substrates Posidoniella sp., Septimyalina burmai, and Leptodesma (Leptodesma) sp.; and the semi-infaunal species Bakevellia sp. The lifestyle and preservation characteristics of bivalves indicate that they were shortly transported before its final deposition, which occurred on a platform, in shallow water. The studied bivalve species are consistent with the permian age of this formation, considered previously by other authors based on the study of ammonites and foraminifera, and support the idea of their relationship with contemporary faunas of North America.

Keywords : Olinalá Formation; bivalves; middle Permian; Mexico.