TRUE STROPHOMENA AND A REVISION OF THE CLASSIFICATION AND EVOLUTION OF STROPHOMENOID AND STROPHODONTOID BRACHIOPODS

The brachiopod superfamily Strophomenoidea is reviewed and reclassifie d, with chief emphasis on the form and evolution of the cardinalia, th e denticulation, the ventral muscle fields, and the dorsal side septa. There are six families without denticulation along the hinge line: th e Christianiidae, Foliomenidae, Glyptomenidae, Leptaenoideidae, Rafine squinidae, and Strophomenidae; and seven families with denticles along the hinge line: the Amphistrophiidae, Douvillinidae, Eopholidostrophi idae, Leptostrophiidae, Shaleriidae, Strophodontidae and Strophonellid ae. A separate superfamily 'Strophodontacea' is not recognized since d enticulation arose polyphyletically, mainly from different stocks with in the Rafinesquinidae. Experimentation in the development of denticle s and crenulations in the Strophomenidae, Leptaeninae and other groups also occurred but was unsuccessful. The form of the cardinalia is the most important character for differentiating families apart from the later denticulate genera, in which parallel evolution of the cardinali a occurred, and the form of the ventral valve muscle field and other s tructures are used. A lectotype is selected for Strophomena planumbona , the type species of Strophomena, and the new genus Palaeoleptostroph ia is erected, with type species Stropheodonta jamesoni, from the lowe r Llandovery (Rhuddanian) of Girvan, Scotland. Brachyprion, Eostropheo donta, Leptaena, Rhenostrophia, and associated genera are revised, and the new family Eopholidostrophiidae is erected.