An unusual occurrence of vascoceratid ammonites in the Bohemian Cretaceous Basin (Czech Republic) marks the lower Turonian boundary between the Boreal and Tethyan realms in central Europe
Abstrakt
An unusual early Turonian ammonite fauna, comprising Fagesia peroni (Pervinquiere, 1907), Fagesia catinus (Mantell, 1822) and Paramammites polymorphus (Pervinquiere,1907), is recorded for the first time from the southern margin of the Bohemian Cretaceous Basin (BCB) in central Europe. The occurrence of these exotic ammonites also constitutes the northernmost record in the Mid-European seaway that links the Boreal and Tethyan realms, because these taxa are missing from the western, eastern and northern parts of the basin as well as from the Saxonian, Bavarian and northern European basins (except Fagesia catinus from western most European parts).
The stratigraphical distribution within the Fagesia catinus Zone, newly documented here for the BCB, is also supported by records of the earliest Turonian inoceramid Mytiloides puebloensis Walaszczyk and Cobban, 2000. The palaeobiogeographical distribution of these ammonites marks a clear boundary in the BCB area and simultaneously documents a significant Tethyan influence in the central European basin during the early Turonian.
This migration pattern is linked to the onset of the Turonian temperature rise and sea level highstand.