Neptunea dominator Mclean & Clark 2023, n. sp.

Neptunea dominator n. sp.

Figures 15 G–J

urn:lsid:zoobank.org:act: B167B455-40EA-4FEE-9865-DFBE9DDEC353

Type locality: Petrel Bank, NE of Semisopochnoi Island, Rat Ids., Aleutian Is., Alaska (54°02.8 N, 179°47.4 W); 256 m (NMFS 23-199701 - 169).

Type material: Holotype: LACM 3582, 111.6 mm. (leg. RNC, 11 July, 1997, trawled, R/V Dominator). Paratypes: Pt 1, LACM 3630, 120.7 mm. N of Amlia Island, Andreanof Ids. (52º33.74 N, 173º17.97 W), 219 m (94- 199401-70); Pt 2, RNC 4621, 51.3 mm. SW of Buldir Island (52°18.5 N, 175°59.0 E), 325 m (NMFS 23-199701 - 243).

Referred material: 1, RNC 3904, 135.1 mm. N of Amlia Island, Andreanof Ids. (52°31.24 N, 173°28.65 W), 224 m (NMFS 143-201001 - 47); 1, RNC 4673, 89.0 mm. SW of Tanaga Island, Andreanof Ids. (51°29.3 N, 178°31.5 W), 210 m (176-201601-242).

Description: Shell moderately large (to 135 mm, RNC 3904), fusiform, white, marked with brown on base and ribs; periostracum lacking; Whorls rounded, suture moderately impressed. Protoconch large, 6.4 mm in diameter, bulbous, projecting, with two whorls; five teleconch whorls, first teleconch whorl rounded, smooth, second teleconch whorl vertically compressed, with five or six even spiral cords. Spiral sculpture of five to seven, rounded, even cords interspaces broader than cords, bearing three to five fine lirae;12–14 cords of lesser strength and more crowded on base. Axial sculpture lacking. Mature lip slightly thickened, scarcely flaring, canal of moderate length, pillar with well-developed siphonal fasciole.

Radula: Somewhat atypical for genus. Rachidian tooth broadly quadrate, strongly indented anteriorly, anteriolateral edges rounded, bearing three short, stout, equal-sized cusps. Lateral teeth long, thick, bearing four cusps rather than the normal three; cusps well-spaced, outer cusp much longer than others, strongly curved, inner cusp about 2/3 as large as outer one, moderately curved; two central cusps much smaller, about half the size of inner cusp, inner one slightly larger than outer one.

Remarks: Differs from Neptunea baxteri n. sp., by 1) a taller, more slender profile and 2) fewer primary spiral cords, with broader interspaces bearing several fine lirae, and 3) in the details of the radular teeth.

Etymology: Named for the NMFS chartered fishing vessel Dominator that collected the holotype.

Distribution: Central and western Aleutians from SW of Buldir Island (175°49 E) to near Amlia Island, Andreanof Ids. (173°28 W), at depths of 210– 325 m.

Habitat: Found on black sand and cobble bottoms at temperatures of 3.2°C–5.2°C.