On some Mississippian (Carboniferous) brachiopods from neptunian dykes of the Harz Mountains (central Germany)

Abstract

Different generations of Mississippian neptunian dykes developed in the drowned Iberg–Winterberg Devonian seamount (Harz Mountains, Germany) yielded poorly diverse and generally small-sized brachiopod faunas dominated by spire-bearers (athyridides, spiriferides) and including several homeomorphic spiriferides. Four limestone levels are distinguished: Erdbach-II Limestone (Scaliognathus anchoralis Zone and basal Pseudognathodus homopunctatus Zone, late Ivorian and basal early Visean), Actinotheca Limestone (Pseudognathodus homopunctatus Zone, Arundian–Holkerian–early Asbian), Goniatite Limestone (Gnathodus bilineatus and Lochriea nodosa zones, late Asbian–early Brigantian), Ibergirhynchia Limestone (Lochriea nodosa Zone, early Brigantian). The faunas (dominant cephalopod facies) of the traditional ‘Erdbach Limestone’ in all older literature related to the Iberg–Winterberg Massif are a mixture of the two older horizons (light crinoidal limestones; late Ivorian to early Asbian), of which the age of their fossil content (especially the well-studied trilobites) needs to be revised by conodonts. New spiriferide genera are described, namely Roemerithyris gen. nov. and Felsithyris gen. nov. with Spirifer macrogaster Roemer 1852 and Felsithyris hercynica gen. et sp. nov. as type species, respectively. The latter species is the most common element of an almost monospecific assemblage of early–middle Visean age. Regeneration traces after fish attacks, developed on a spiriferide shell, are illustrated.