Morphology, systematics, and evolution of Middle Devonian Ambocoeliidae (Brachiopoda), western New York

The internal morphology of ambocoeliid brachiopods from the middle Devonian Hamilton Group of western New York indicates a need for several taxonomic revisions. "Ambocoelia, praeumbona is transferred to Emanuella. "Ambocoelia' spinosa and "A.' nana represent Crurispina n. gen. Specimens of species belonging to Crurispina have moderately well developed crural plates, and, accordingly, they are assigned to the subfamily Rhynchospiriferinae. The diagnosis of the subfamily Ambocoeliinae is emended to include species with tiny crural plates. Ambocoeliid specimens from the Levanna Shale Member of the Skaneateles Formation, formerly referred to Echinocoelia, reveal several elaborate features in the pedicle valve, including an apical plate and a hollow tube supported by a median septum. These specimens represent a new genus and species, Mucroclipeus eliei. The homeomorphy found in the shape and size of these ambocoeliids may be the result of paedomorphosis. Additionally, their pattern of occurrence and minute size suggest that they attained their paedomorphic state through progenesis. -from Authors