CHALLENGES IN ORBITOLINID IDENTIFICATION AND BIOSTRATIGRAPHIC CONSEQUENCES: AN APTIAN EXAMPLE

Abstract

The much-cited importance of Orbitolinidae in biostratigraphy depends on the species and time-interval under consideration. In any case, correct species identification is of primary importance as the basis for drawing conclusions. This task is best achieved in an assemblage where centered sections (axial and transverse) showing all details of the complex megalospheric embryo are available. Difficulties in the correct interpretation of oblique sections is exemplified by an example from the Aptian of Turkey, respectively Praeorbitolina versus Mesorbitolina. Resulting differences in species determination not only has an impact on age interpretation, but also associated geologic-tectonic conclusions, as well as basic taxonomic data (e.g., stratigraphic ranges, statistics on stage diversities).