Inoceramids from the Upper Campanian and Lower Maastrichtian of the Tercis section (SW France), the Global Stratotype Section and Point for the Campanian – Maastrichtian boundary; taxonomy, biostratigraphy and correlation potential

Abstract

Thirty-three inoceramid species from the upper Upper Campanian and Lower Maastrichtian of the Tercis section (SW France), the Global Boundary Stratotype Section and Point for the Campanian – Maastrichtian boundary, are described, of which 8 are left in open nomenclature. Two species are described as new: Endocostea jolkicevi and “Inoceramus” cobbani. The described species represent four inoceramid genera Cataceramus HEINZ, 1932, Sphaeroceramus, HEINZ, 1932, Enodcostea WHITFIELD, 1877, Trochoceramus HEINZ, 1932, and thirteen species are referred to the genus “Inoceramus” sensu lato. The inoceramids allow the subdivision of the upper Upper Campanian and of the Lower Maastrichtian into seven zones and their correlation with the ammonite scheme, as well as with the chronostratigraphic standard. The Campanian – Maastrichtian boundary falls in the topmost part of the Inoceramus” redbirdensis Zone, and the base of the successive, Endocostea typica Zone is a good proxy for this stage boundary. Besides the Trochoceramus costaecus Zone all other zones are also distinguishable in the US Western Interior.