Brachiopod Antiquatonia Coloradoensis(Girty) from the Upper Morrowan and Atokan211 (Lower Middle Pennsylvanian) of the United States

摘要

Primary type specimens and topotypes of the large, semireticulate productid,211u001eProductus inflatus var. coloradoensis (Girty), collected near Leadville, Colo., 211u001eform the basis for the redescription of this species. The type locality, for the 211u001efirst time, is firmly established stratigraphically in upper Morrowan (lower 211u001eMiddle Pennsylvanian) rocks of the lower part of the Belden Shale. The 211u001eidentification and clarification of several previously poorly known physical 211u001efeatures affirm assignment of Girty's species to the genus Antiquatonia 211u001eMiloradovich, as currently restricted and understood. Detailed analysis of other 211u001ecollections of brachiopods assigned to A. coloradoensis and to related taxa 211u001econfirms that the probable ancestor of A. coloradoensis is the lower and middle 211u001eMorrowan A. morrowensis (Mather), which was described from the Ozarks region of 211u001enorthwestern Arkansas.