New annulate Carboniferous orthoconic and cyrtoconic cephalopods of the family Brachycycloceratidae Furnish, Glenister & Hartman, 1962

The Carboniferous orthoconic or slightly cyrtoconic cephalopod family Brachycycloceratidae Furnish, Glenister &; Hansman, 1962 is well described based on material from North America, whereas the Early Carboniferous European occurrences of this family are much less well-known. Almost all records from the Rhenish Mountains have been assigned to the single species Brachycycloceras scalare (d’Archiac &; de Verneuil, 1842). This species is revised here and used as the type species of the genus Rhenocycloceras gen. nov. The new Early Carboniferous species Rhenocycloceras conicum sp. nov. and R. denckmanni sp. nov. from the Rhenish Mountains of Germany, R. macdiarmadai sp. nov. from Co. Leitrim in Ireland and R. africanum sp. nov. from the Anti-Atlas of Morocco are described. Additionally, two new Early Carboniferous species of Caneycycloceras Niko &; Mapes, 2011 are described from the Rhenish Mountains;; these are C. rotersorum sp. nov. and C. fuerstenbergorum sp. nov. The early Late Carboniferous species B. koninckianum (d’Orbigny, 1849) is discussed on the basis of material from the type locality in Belgium.