Neptunea baxteri, 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 : 177-179

Neptunea baxteri n. sp.

Figures 15 D–F

urn:lsid:zoobank.org:act:653CFCAF-AD61-4943-8DF1-BF05775C52DF

“ Neptunea insularis convexa , ” Matsukuma, et. al., 1991, pl. 76, fig. 4 non convexa Goryachev, 1978.

“ Neptunea sp. ” of Higuchi, 2006, pl. 77, lower left.

Type locality: N of Umnak Island, Fox Ids., Aleutian Is. , Alaska (53°24.7 N, 168°41.4 W); 270–296 m ( NMFS 95-199401 - 26 ) .

Type material: Holotype: LACM 3581 , (leg. 10 June, 1994, trawled, R/ V Pacific Knight) ; Paratypes: Pt 1, LACM 3637, 113.1 mm. NE side Unalaska Island, Fox Ids. (54°01 N, 166°18 W), 84 m; Pt 2, LACM 3638, 103.1 mm. S of Adak Island, Andreanof Ids. (51°45 N, 176°45 W), depth unknown; Pt 3, LACM 3639 , 88.8 mm. SW of Chernabura Island, Shumagin Islands (54°27 N, 159°45 W), 128 m; Pt 4 & 5, SBMNH 464997 , 47 mm, 80.7mm, & 83.1 mm, S of Akutan Island, Fox Ids., (5331.75 N, 16547.92 W), 125 m (100-199601-19); Pt 6 & 7, USNM 1606665 , 89.6 & 72.44 mm, S of Amutka Island, Islands of Four Mountains (52°29.46 N, 171°06.93 W), 332 m ( NMFS 176-201401 - 40 ); Pt 8, CASIZ 236194 , 70.8 mm, S of Seguam Island, Andreanof Ids. (51°58.56 N, 172°36.86 W), 167 m ( NMFS 94-200201 - 192 ); Pt 9, CASIZ 236195 , 66.3 mm. S of Seguam Island, Andreanof Ids. (51°58.67 N, 172°35.4 W), 173 m ( NMFS 23-199701 - 78 ); Pt 10, RNC 4766 , 89.5 mm. Seguam Pass , NE of Amlia Island, Andreanof Ids. (52°10.08 N, 173°06.08 W), 92 m ( NMFS 23-199701 - 66 ); Pt 11, RNC 4614, 133.8 mm. S of Herbert Island, Islands of Four Mountains (52°38.8 N, 170°12.5 W), 233 m ( NMFS 57-200201 - 48 ) .

Referred material: 1, RNC 4670 , 54.7 mm. E of Semidi Islands (56°05.55 N, 156°17.03 W), 215 m ( NMFS 143-200301 - 177 ) .

Description: Shell of moderate size (to 133 mm), pyriform, whorls rounded except for slight subsutral concavity, suture moderately impressed; white to brown, with very thin or absent periostracum. Protoconch large, 3.9–5.4 mm in diameter, bulbus, projecting, with 2 whorls; teleconch with four whorls, early whorls with 9–11 fine spiral cords, adult whorls with 11–20 rounded, even spiral cords above suture, interspaces narrower; cords weaker and more crowded on base; columella somewhat concave. Mature lip slightly thickened, hardly flaring; canal moderately short, twisted; pillar with poorly developed siphonal facsiole; mature lip slightly thickened and flaring.

Radula: Rachidian tooth broad, quadrate, strongly indented anteriorly, bearing two or three sub-equal cusps (central cusp when present, slightly longer than outer ones). Lateral teeth large, tri-cuspid, outer cusp relatively thick, strongly curved, much larger than others; central cusp very short, slightly bent; inner cusp about twice as large as central one, rather thick, curved.

Remarks: Neptunea baxteri is similar to Neptunea dominator n. sp. but differs by 1) it’s shorter, broader profile, and 2) more numerous primary spiral cords. Neptunea baxteri lays stacked egg capsules, similar to those of Neptunea lyrata (Gmelin, 1791) and Neptunea ventricosa (Gmelin, 1791) . Egg capsules triangular in shape, 20 x 18 mm, stacked in alternating three capsule layers giving a hexagonal cross-section to egg towers immerging hatchlings 5–6 mm in length.

Etymology: The name honors the late Rae Baxter of Seldovia Alaska, a former Alaska Department of Fish and game biologist who spent many years studying the mollusks of Alaska, and who collected some of the first specimens.

Distribution: Semidi Islands, western Gulf of Alaska (156°17 W) (RNC 4616) to Adak Island, central Aleutians (176°45 W) (LACM 3638), at depths of 84– 296 m.

Habitat: Found on black sand, gravel and pebble bottoms (sometimes mixed with cobbles) with bottom temperatures of 3.6–5.5°C, but most commonly at temperatures of 4.1–4.5°C.

Figures

FIGURE 15. A–C. Neptunea aleutica n. sp.; A. Holotype, LACM 3580, S of Oglodak, 273 m, 108.5 mm; B. Paratype, RNC 4715, E of Kiska Island, 252 m, 107.3 mm; C. Radula, Paratype, RNC 4715, bar = 200 µm; D–F. Neptunea baxteri n. sp.; D.–Holotype, LACM 3581, N of Umnak Island, 270–296 m, 114 mm; E. Paratype, RNC 4766, NE of Amlia Island, 92 m, 89.5 mm; F. Radula, Paratype, CASIZ 236196, bar = 200 µm. G–J. Neptunea dominator n. sp. G. Holotype, LACM 3582, Petrel Bank, 256 m, 111.6 mm; H. RNC 4673, SW of Tanaga Island, 210 m, 89.0 mm; I. Paratype, RNC 4621, SW of Buldir Island, 325 m, 51.3 mm; J. Radula, holotype, bar = 200 µm.