Bajocian stephanoceratid ammonites and their stratigraphy from Dorset, UK with reference to the work of András GALÁCZ

Abstract

The Inferior Oolite Formation of Dorset includes Lower Bajocian strata often rich in stephanoceratid ammonites comparable with assemblages from the rocks of the Transdanubian Central Range (W Hungary) that are the subject of research by András Galácz, specifically Lokuticeras. In Dorset the stratigraphical occurrence of the ‘Lokuticeras morphology’ can be traced over a range of strata from the Sauzei and Humphriesianum zones and the assemblage composition of the biohorizons in which they occur identified. Lokuticeras is most abundant in Dorset in the uppermost Humphriesianum and Blagdeni subzones of the Humphriesianum Zone. Specimens from three Dorset locations are figured facilitating comparison with the Hungarian specimens. Type species Lokuticeras rossbrunnense is common at the Humphriesianum–Blagdeni subzonal transition. A new biohorizon is erected Lokuticeras rossbrunnense nov. as the lowest biohorizon of the Blagdeni Subzone facilitating correlating some areas of Europe. A critical review is made of previously published specimens and their affinities