Inoceramids and biozonation across the Turonian – Coniacian boundary (Upper Cretaceous) at El Rosario, Coahuila, northeastern Mexico

摘要: The Rosario section in northern Coahuila, northeastern Mexico, contains a complete record of sediment across the Turonian–Coniacian boundary. Here we describe inoceramids and biozonation based on these bivalves. Inoceramus longealatus, Mytiloides herbichi, M. incertus, scupini, Didymotis costatus, Cremnoceramus waltersdorfensis waltersdorfensis, C. hannovrensis, deformis erectus, crassus inconstans, were identified at El Rosario. uppermost Turonian scupini w. zones lower Coniacian inconstans are well represented much more expanded than sections US Western Interior Europe. index for base Coniacian, is also present, although few data exist to date from critical Turon ian–Coniacian boundary level. Ammonites rare, mostly endemic provide resolution inoceramids. We suggest that various acmes observed driven by local or regional rather global causes. provides an inoceramid