Ammonite biostratigraphy of the uppermost Hauterivian in the Betic Cordillera (SE Spain)

A detailed analysis of the stratigraphic distribution of ammonites from fourteen sections in the External Zones of the Belie Cordillera has enabled us to identify accurately the sequence of bioevents that take place throughout the uppermost Hauterivian and to propose a more precise biostratigraphic scheme for this interval. Thus, we have divided the two currently admitted zones (the Crioceratites balearis Zone and the Pseudothurmannia angulicostata auct. Zone) into several subzones. Four subzones can be recognised within the Cr. balearis Zone. The base of each subzone is defined by the first occurrence of one of four successive species belonging to the same Crioceratites lineage. These species are: Cr. balearis, Cr. binelli, Cr krenkeli and Cr. angulicostatus. The Ps. ohmi Zone (which replaces the classical Ps. angulicostata Zone) can be divided into three subzones characterised by three successive species of the genus Pseudothurmannia: Ps. ohmi, Ps mortilleti (here considered as a senior synonym of Ps. catulloi) and Ps. picteti. According to the current definition, the first occurrence of Taveraidiscus hugii (OOSTER) marks the lower boundary of the Barremian stage. This event fits into a major faunal-renewal episode that begins in the upper part of the Ps. picteti Subzone. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.