TY - JOUR A1 - Paul,C.R.C. T1 - Prokopius, a new name for “Hippocystis sculptus” Prokop, 1965, and the status of the genus Hippocystis Bather, 1919 (Echinodermata; Diploporita) JF - Bulletin of Geosciences JA - Bull. Geosci. Y1 - 2018 VL - 93 IS - 3 SP - 337 EP - 346 CY - Prague PB - Czech Geological Survey SN - 1803-1943 (online), 1802-6222 (print) AV - Free KW - Diploporita KW - Hippocystis KW - Aristocystitidae KW - Prokopius gen. nov. KW - Ordovician KW - Sandbian AB - Bather proposed the genus Hippocystis for some Czech diploporites with horseshoe-shaped diplopores first described by Barrande. Bather cited Aristocystites subcylindricus Barrande as the type species and identified a lectotype, but no specimen accepted by Bather as A. subcylindricus preserved the oral area. Bather believed Aristocystites had irregular haplopores and Hippocystis horseshoe-shaped diplopores without intermediates. In 1965 Prokop redescribed one of Barrande’s original specimens of ?A. subcylindricus as Hippocystis sculptus (Barrande). Its oral area has four ambulacral facets, whereas Aristocystites is unique among the Aristocystitidae in having only two. A complete specimen of A. subcylindricus with the oral area preserved shows only two ambulacral facets. Thus, the type species of Hippocystis belongs to Aristocystites, of which Hippocystis becomes a junior synonym. This leaves ’Hippocystis’ sculptus without a valid generic name. The new name Prokopius is proposed for it. Parsley has shown that horseshoeshaped diplopores also occur in A. bohemicus, type species of Aristocystites. Functional analysis of horseshoe-shaped diplopores suggests they are likely to have evolved repeatedly and so make a poor generic criterion. Characteristic oral areas are much more reliable. Prokopius is distinguished by having an oval mouth, surrounded by eight plates, as in all other aristocystitids, with four vertical ambulacral facets, a zigzag hydropore aligned parallel to the oro-anal line and all these features on a raised oral prominence. ER -