Pterygia, RODING, 1798

GENUS PTERYGIA RÖDING, 1798 View in CoL

( FIGS 31, 32A–C)

Type species: Voluta dactylus Linnaeus, 1767 ; SD, Dall (1915: 52).

Synonym: Cylindromitra P. Fischer, 1884 . Type species: Cylindra coronata Schumacher, 1817 (objective synonym of Voluta crenulata Gmelin, 1791 ); by typification of replaced name ( Cylindra Schumacher, 1817 , non-Illiger, 1802; itself by M) Acuticylindra Iredale, 1929 . Type species: Voluta nucea Gmelin, 1791 ; OD.

Diagnosis: Shell small to medium sized (20–70 mm), ovate or ovate-elongate, with very low spire and tall aperture. Protoconch cyrtoconoid, with about three smooth evenly convex whorls. Spire height attaining only about 10–15% of total shell height, with only three to four whorls exposed, and a proportionally very high last adult whorl. Suture adpressed. Last adult whorl convex or strongly convex, smooth or with dominating spiral or cancellate or crenulate sculpture. Spiral elements represented by fine grooves or cords that can be fine or wide, undulating, rounded or resembling scales tiling in posterior direction. Siphonal notch distinct. Aperture elongate, usually narrow. Outer aperture lip convex, smooth or denticulate, inner lip calloused, bearing six to eight subequal columellar folds. Shell off-white, whitish or brownish or with a pattern of red or orange bands. Radula very narrow, consisting of rachidian only, bow-shaped, bearing multiple cusps, or with a single blunt medial cusp and lateral serration ( Fig. 32A–C).

Distribution: Indo-Pacific, subtidal, mostly on coral rubble, one species occurs on mud.

Species included: Pterygia arctata (G. B. Sowerby II, 1874) 3, P. conus (Gmelin, 1791) 3, P. crenulata (Gmelin, 1791) 2, P. dactylus (Linnaeus, 1767) 1, P. fenestrata (Lamarck, 1811) 1, P. gorii ( Turner, 2007) 3, P. japonica Okutani & Matsukuma , 19823, P. jeanjacquesi Bozzetti , 20103, P. morrisoni Marrow , 20163, P. nucea (Gmelin, 1791) 2, P. purtymuni Salisbury , 19983, P. scabricula (Linnaeus, 1767) 3, P. sinensis (Reeve, 1844) 1, P. undulosa (Reeve, 1844) 3.

Remarks: The genus Pterygia is morphologically distinctive thanks to its ovate shell with multiple columellar folds, and monoserial radula. In the present study, we leave the contents of the genus unchanged; however, some species currently classified in other genera (e.g. Scabricola potensis ) may actually belong to Pterygia . Conical shells resembling those of Pterygia are found in Imbricaria and Imbricariopsis gen. nov., which are, however, phylogenetically very distant from Pterygia and are characterized by a triserial radulae.