The athyridoids of the transitional beds between Bellerophon and Werfen Formations (uppermost Permian, Southern Alps, Italy)

The transitional beds between Bellerophon and Werfen formations, few centim etres thick and latest Permian in age, contain a brachiopod fauna with a re latively rich athyridoid assemblage, among which Janiceps is the most commo n and characteristic genus. The internal morphology of the type species (J. peracuta) is here described for the first time, and a taxonomical revision of the South Alpine species is proposed. The new subfamily Janicepsinae is proposed, which contains Janiceps and the new genus Comelicothyris. Among the latter genus, Comelicothyris laterosulcata n. sp. is suggested. Lectoty pes are selected and illustrated for Spirigera janiceps Stache, S. confinal is Stache, S. bipartita Stache, S. ? arcbimedis Stache, Spirifer ? sextensi s Stache, Athyris irregularis Merla,A, semilunaris Merla, and A. janiceps v ar. globulus Merla. The athyridoids of the transitional beds are characterized by a broad morph ological variability which induced past authors to create many species and "varieties", generally on the basis of a single or few individuals. As conc erns Janiceps, only four species -versus the 14 species and 7 "varieties" c ited in the literature of the Southern Alps- are here considered valid [J. peracuta (Stache), J. cadorica (Stache), J. papilio (Stache), and J. bipart ita (Stache)]. Besides, other four species are identified here; these are: Comelicothyris recticardinis (Merla), Septospirigerella ? sp., Spirigerelli nae gen. et sp. indet., and Comelicania merlai Posenato.