Donetzoceras, a Mid-Carboniferous (Westphalian) Index Ammonoid

The generic concept of Donetzoceras Librovitch (1946) has been clarified by comparison of large numbers of specimens representing all growth stages from Westphalian strata in northern Algeria with type and reference material from Great Britain and the Soviet Union. The genus includes several species referred previously to Anthracoceras Frech (1899), including A. aegiranum Schmidt (1925) (=A. hindi Bisat, 1930) and possibly A. cambriense Bisat (1930). The Algerian specimens are described as D. pareyni n. sp. Donetzoceras is a distinctive index taxon in the Westphalian Series of the Upper Carboniferous.