Volutopsius nanus, Mclean & Clark, 2023

Mclean, James H. & Clark, Roger N., 2023, Seven new genera and thirty-four new species of buccinoid gastropods (Neogastropoda: Buccinidae) from the Aleutian Islands, Alaska, Zootaxa 5351 (2), pp. 151-201 : 188

Volutopsius nanus n. sp.

Figures 19 A–C urn:lsid:zoobank.org:act:B6C52DEE-CFE6-4858-9013-AE5100D4E120

Type locality: SW of Buldir Island, Aleutian Is. , Alaska (52°18.5 N, 175°49.0 E), 325 m ( NMFS 23-199701 - 243 ) .

Type: Holotype, LACM 3588 , 35.6 mm (leg. RNC 9 Aug. 1997) ; Paratypes: Pt 1–3, LACM 3669 , 20.8–29.5 mm. SW of Agattu Island, Near Ids. (52°13.5 N, 173°27.8 E), 169 m ( NMFS 23-199701 - 229 ); Pt 4, SBMNH 169015 , 33.4 mm. SE of Buldir Island (51°24.6 N, 175°20.0 E), 187 m ( NMFS 94-200201 - 158 ); Pt 6, USNM 1606664 , 35.1 mm. SE of Buldir Island (51°24.6 N, 175°20.0 E), 187 m ( NMFS 94-200201 - 158 ); Pt 7, RNC 4711 , 40.0 mm. (Type locality).

Referred material: RNC 4888 , 1 sp., 36.8 mm. SW of Agattu Island , Near Ids. (52°13.5 N, 173°27.8 E), 169 m ( NMFS 23-199701 - 229 ) ; RNC 4901 , 15.34 mm. ESE of Buldir Island (52°20.61 N, 176°22.79 E), 227 m (23- 2000-01-173) .

Description: Small for genus, height to 40.0 mm; suture moderately impressed, whorls rounded. Protoconch, one whorl, 3.7–4.1 mm in diameter, with four spiral cords; teleconch with three whorls; spiral sculpture of very fine lirae, with slightly wider interspaces, about 30 on penultimate whorl, and continuing on below the suture. Aperture a little more than half of shell height, outer lip flared; canal short, broad. Operculum small, less than half of aperture height.

Radula: Typical for subfamily, rachidian tooth with four subequal cusps; lateral teeth with two large, heavy cusps, outer cusp strongly curved, inner cusp straight.

Remarks: This is the smallest known species of Volutopsius , and probably cannot be confused with any congeners. Volutopsius middendorffi (Dall, 1891) is similar but much larger, reaching over 11 cm, and has a pinkish protoconch.

Etymology: Named for its small size, from the Latin nanus, dwarf. Volutopsius nanus is considerably smaller than all other known Volutopsinae.

Distribution: This small species is restricted to the western-most Aleutians, from the vicinity of Buldir Id. (176°22 E) to Attu Id. (173° E), at depths of 169– 325 m.

Habitat: Lives on black sand and gravel, at temperatures of 3.6°–4.1° C.

Figures

FIGURE 19. A–C. Volutopsius nanus n. sp.; A. Holotype, 3588, SW of Buldir Island, 325 m, 35.6 mm; B. Holotype, close-up of sculpture; C. Radula, Paratype, RNC 4711, bar = 200 µm; D, E. Volutopsius gracilis n. sp. D. Holotype, LACM 3589, N of Unimak Island, 80 m, 142.1 mm; E. Radula, Paratype, RNC 5031, bar = 200 µm; F, G. Volutopsius castaneum (Mörch, 1857); F. RNC 4801, Adak Island, 13 m, 76.2 mm; G. Radula, RNC 4801, bar = 200 µm; H, I. Volutopsius stefanssoni Dall, 1919; H. RNC 5038, Chukchi Sea, 42 m, 79.0 mm; I. Radula, RNC 4272, bar = 200 µm; J. Volutopsius stefanssoni var. simplex, RNC 4005, N of Shemya Island, 115 m, 99.6 mm; K–M. Crebrivolutopsius labidentatus n. sp. K. Holotype, CASIZ 137734, Petrel Bank, 213 m, 107.6 mm; L. RNC 4658, close-up of labial teeth, S of Amchitka Island, 388 m, 72.3 mm; M. Radula, RNC 4658, bar = 200 µm.