Carina Klein examines the quality of the existing modern ammonoid zonation based on three methods, being Unitary Associations (UA), Constrained Optimization (CONOP) as well as Ranking and Scaling (RASC). The author sets out which of these three methods is best suitable to refine these zones. The results obtained are compared to each other with regard to ammonoid succession and resolution as well as with empirical data from selected reference sections. The analysis reveals that the UA and RASC methods are the most suitable since the results best mirror the empirical data from the single outcrops.

Carina Klein completed her Master's degree at the Freie Universität Berlin in 2014. Afterwards, she started her PhD project at the Museum für Naturkunde Berlin studying major patterns of developmental trajectories in the evolutionary history of the Ammonoidea.

Geological and Stratigraphical Background.- Ammonoid Species across the Devonian-Carboniferous Boundary and Localities in the Rhenish Mountains (Germany).- Introduction and Comparison of the Methods UA, CONOP, RASC.- Comparison with the Existing Ammonoid Zonation and Suggestion of New Bio Zones.