Subestea Cotton, 1944

Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2023, Shallow-water Rissoidae of the genera Alvania Risso 1826 Haurakia Iredale 1915 Parashiela Laseron 1956 Simulamerelina Ponder 1985 and Subestea Cotton 1944 Gastropoda Caenogastropoda Rissooidea from French Polynesia with the description of a new deep-water genus, Zoosystema 45 (25), pp. 803-892 : 872

Genus Subestea Cotton, 1944

Subestea Cotton, 1944: 292 .

TYPE SPECIES. — Alvania seminodosa May, 1915: 94-95 ; plate VI, fig. 30 (synonym of Subestea australiae ( Frauenfeld, 1867)) by original designation.

DIAGNOSIS. — Shell of small size for the family (height c. 2 mm); elongate-conical to elongate-oval, rather robust, non-umbilicate, with spiral and axial sculpture varying in strength, spiral sculpture usually stronger than axial sculpture, sometimes subequal, sometimes almost obsolete. Microsculpture from dense spiral stretches. Aperture simple, subcircular. Protoconch paucispiral, dome-shaped, of about 1 ½ whorls, sculptured with smooth spiral lirae, interspaces with granules or micro pits (from Ponder, 1985 with personal modifications).

Head-foot: cephalic tentacles moderately long, ciliated ventrally, with parallel sides or slightly expanded distally; small anterior pallial tentacle and very short, broad, posterior metapodial tentacle; indistinct, triangular anterior pedal gland and no posterior pedal gland. Operculum: oval, thin, nucleus eccentric, last whorl large (after Ponder 1985: 59).

REMARKS

Subestea Cotton, 1844 was sometimes ranked as a subgenus of Onoba H. Adams & A. Adams, 1852 ( Ponder 1985: 59), and is currently regarded as a valid genus ( Criscione et al. 2016: 13). It comprises a small group of six species ( MolluscaBase 2023e) living from the lower intertidal to the continental shelf, where they are often associated with algal facies, in the tropical western and southern Atlantic, the tropical Indo-West Pacific, and South Africa. A single, undescribed species has been found in the Tuamotu and Gambier.