Euspiralta okinawaensis, Monsecour & Raines, 2024

Monsecour, Kevin & Raines, Bret K., 2024, New species and genus of Columbellidae (Gastropoda: Buccinoidea) from the Western Pacific, Zootaxa 5514 (4), pp. 353-367 : 356

Euspiralta okinawaensis sp. nov.

Figures 1 M–R

Type Material. Holotype LACM 3807 , 1 Paratype LACM 3808 , 2 Paratypes MNHN-IM-2018-1777 , 2 Paratypes CKM, 2 Paratypes MSF fa176 .

Type Locality. Japan, Okinawa, Onna, Horseshoe , 26.5054 o N, 127.8459 o E, 35 m deep.

Distribution. Currently only known from the type locality.

Description. Shell of moderate size for genus, up to 3.3 mm; biconical, elongate. Protoconch paucispiral, rather elongated, of 1.7–1.8 smooth whorls. Transition to teleoconch weakly visible. Teleoconch of 3.1–3.3 whorls, slightly convex; suture slightly impressed. Surface smooth apart from occasional very weak axial ribs, and basal cords on last whorl, clearly present on last whorl, extending just below adapical edge of columella.Aperture narrow, elongate, 46–52% of shell height. Outer lip clearly thickened, bearing continuations of basal cords on abapical end. Inside denticulate, with 4–6 denticles, adapically much stronger, abapically nearly obsolete. Adapical end of outer lip with weak sinus. Columellar and parietal callus, not denticulate. Siphonal canal short, half-open, slightly recurved. Teleoconch whorls translucent, background color yellow-orange, with faint white spiral band, at mid-height of last whorl. Protoconch yellow-orange. Aperture and columella off-white to yellow-orange. Radula not studied. Height of holotype: 2.7 mm.

Remarks. Some paratypes show no further pattern (figs 1 Q–R), while others show a weak whitish spiral band at mid-height of last whorl (figs 1 O–P). The genus Euspiralta had been known by only one other member: Euspiralta santoensis (figs 1 K–L) originating from Santo Island, Vanuatu (see Monsecour & Pelorce 2013), with the same yellow-orange color as the new species. However, Euspiralta okinawaensis differs in its slightly smaller size, wider shell, different protoconch shape, lower number of teleoconch whorls and wider aperture.

Etymology. Latin adjective formed from the type locality, Okinawa.

Figures

FIGURE 1. A–F, Ascalista saipanensis sp. nov.; A–B, Holotype. LACM 2709, 3.3 mm; C–D, Paratype 1. CKM, 3.1 mm; E–F, Paratype 2. MSF fa175, 3.0 mm; G–H, Ascalista letourneuxi Monsecour & Monsecour, 2015, French Polynesia, Austral Islands, Rapa Island, Paratype CKM, 4.0 mm; I–J, Ascalista polita (G. & H. Nevill, 1875), Philippines, Mactan Island, Punta Engano, CKM, 3.6 mm; K–L, Euspiralta santoensis Monsecour & Pelorce, 2013, Vanuatu, Segond Channel, CKM, 3.2 mm; M–R, Euspiralta okinawaensis sp. nov.; M–N, Holotype. LACM 3807, 2.7 mm; O–P, Paratype 1. LACM 3808, 2.8 mm; Q–R, Paratype 2. MNHN-IM-2018-1777, 2.9 mm.