Reticulinella kaeveri CHERCHI, RADOIÄ IÄ & SCHROEDER: A marker for the middle-upper Turonian in the shallow-water carbonate facies of the peri-Adriatic area

Reticulinella kaeveri CHERCHI, RADOIÄ IÄ & SCHROEDER is recorded for the first time in the Upper Cretaceous shallow-water carbonates of the southern Apennines. The narrow stratigraphical range and the wide geographical distribution of this species makes it a very valuable biostratigraphic marker in the Turonian of the peri-Adriatic carbonate platforms. Strontium isotope stratigraphy of well preserved rudist shells from levels containing Reticulinella kaeveri, or immediately above its last occurrence, allows the chronostratigraphic age of this species to be defined more precisely. However, owing to the presence of a distinct late Turonian minimum in the marine reference curve, the strontium isotope ratios of the studied samples are compatible both with a late middle Turonian (upper part of the Romaniceras deverianum ammonite zone) and with a late Turonian age (Subprionocyclus neptuni ammonite zone).