Prokopius, a new name for “Hippocystis sculptus” Prokop, 1965, and the status of the genus Hippocystis Bather, 1919 (Echinodermata; Diploporita)

Abstract

Barrande (1887) described the new genus Aristocystites, type species A. bohemicus Barrande, 1887. Aristocystites is characterized by a large, oval to pyriform theca, usually with a distinct basal attachment scar. The mouth is elongated perpendicular to the oro-anal line and bears two weak ambulacral facets at either end. An elongate hydropore and circular gonopore lie between the mouth and the large, angular periproct. The hydropore is nearer the mouth. Plates are covered with irregular diplopores, but are smooth and plate sutures very difficult to distinguish. In table 2, Barrande (1887, p. 65) listed seven other specific names doubtfully attributed to Aristocystites. These included '?A. sculptus Barrande, 1887' and '?A. subcylindricus Barrande, 1887, var. de bohemicus'. Barrande (1887, p. 113, pl. 6, figs 28, 29) described and illustrated the unique example of ?A. sculptus and stated its only distinguishing character was the presence of tumid plates. He also described and illustrated (Barrande 1887, p. 114, pl. 6, figs 26, 27, pl. 13, figs 1-21) '?A. sub-cylindricus Barrande, 1887, var. de bohemicus'. The single example illustrated on plate 6 came from the same locality (Chrustenitz) as ?A. sculptus and clearly shows the oral area. The distinguishing characters of ?A. subcylindricus were a rounded base lacking an attachment scar and horseshoe-shaped diplopores. Bather (1919a, p. 72) erected the genus Hippocystis in one of a series of notes (Bather 1918a, b; 1919a-e) commenting on F.R.C. Reed's monograph describing Ordovician cystoids from Yunnan, China (Reed 1917). Bather (1919a) compared Sinocystis Reed, 1917, with other genera in the family Aristocystitidae and in doing so pointed out that some specimens of Aristocystites Barrande, were characterized by horseshoe-shaped diplopores. He considered these diplopores to differ sufficiently from those of Aristocystites proper to justify characterizing a new genus. Bather (1919a, p. 72) designated A. subcylindricus Barrande as the type species of Hippocystis and specified the original of Barrande's (1887, pl. 13, figs 1-4) as the 'holotype' (Bather 1919a, p. 73). We 337

New Middle and Late Ordovician cornute stylophorans (Echinodermata) from Morocco and other peri-Gondwanan areas

“…In the lowermost part of the formation, oolitic iron ores (Zdice-Nučice ore horizon) yielded distinct and more diverse assemblages . Echinoderms are much less common and diverse than in the underlying Letná Formation (Barrande 1872(Barrande , 1887Havlíček 1982Havlíček & Fatka 1992;Prokop & Petr 1999;Noailles et al 2014;Paul 2018). They can be assigned to two distinct communities.…”

The diploporite blastozoan Glyptosphaerites (Echinodermata: Blastozoa) and the origin of diplopores

“…This paper forms one of a series prepared in anticipation of the proposed revised edition of the Treatise on Invertebrate Paleontology, Part S, which will cover the Blastozoa. The papers aim to redescribe to modern standards key genera that are either new (Paul & Gutiérrez-Marco 2020), or have been misclassified (Paul 2018) or inaccurately described (Paul & Toom 2021). The aim is to establish the basic morphological facts before attempting a comprehensive cladistic analysis.…”

Pentaradiate diploporites (Echinodermata) from the Spanish Middle Ordovician and their taxonomic significance

“…Triamara, the only aristocystitid included within 'Holocystites' s.l., has three ambulacra, each with a pair of facets and would not be included in the Hippocystinae now Paul and Parsley (2019). have shown that the type species of Hippocystis is a species of Aristocystites s.s Paul (2018). proposed the new name Prokopius for Hippocystis sculptus(Barrande, 1887).…”