Laevisipho kessleri Mclean & Clark 2023, n. sp.

Laevisipho kessleri n. sp.

Figure 18 E–G urn:lsid:zoobank.org:act: A213A933-2C42-4A28-9E75-B6DE269A66FB

Type locality: S of Seguam Island, Aleutian Is., Alaska (51°52.62 N, 172°33.61 W); 147 m (NMFS 23-199701 - 95).

Type material: Holotype LACM 3586, 64.6 mm. (leg. RNC 7 July, 1997, trawled, R/V Dominator); Paratypes: Pt 1, LACM 3632, 74.4 mm. S of Seguam Island, (51°57.9 N, 172°17.8 W), 104 m (NMFS 95-199401 - 93); Pt 2, SBMNH 169010, 59.6 mm, N of Atka Island, Andreanof Ids. (52°08.55 N, 175°16.99 W), 212 m (NMFS 94- 199401 - 156); Pt 3, SBMNH 174793, 66.7 mm, Seguam Pass (5158.35 N, 17236.86 W), 167 m. (NMFS 94-200202 - 192); Pt 4, USNM 1606666, 57.4 mm. S of Amlia Island, Andreanof Ids. (51°57.96 N, 172°37.93 W), 220 m (NMFS 23-199701 - 79); Pt 5, RNC 4519, 81 mm. N of Atka Island, Andreanof Ids. (52°10.96 N, 174°33.53 W), 116 m (NMFS 23-199701 - 103).

Referred material: RNC 4940, 96.3 mm. N of Amlia Island, Andreanof Ids. (52°14.89 N, 173°00.11 W), 250 m (NMFS 176-201601 - 55); RNC 4911, 58.6 mm. S of Yunaska Island, Islands of Four Mountains (52°46.9 N, 170°41.4 W).

Description: Shell of medium size (to 96 mm, RNC 4940), fusiform; light brown, solid; periostracum lacking. Whorls rounded; suture impressed. Protoconch extended, 2.5 whorls, 5.1–5.3 mm in diameter, 4–4.5 teleconch whorls surface usually smooth, axial sculpture lacking, spiral sculpture usually lacking, or rarely with a few, very faint, fine, irregular, spiral cords. Aperture oval, much less than half of shell height; olumella only slightly concave, mature lip thickened, but not flared; canal of moderate length, narrow, nearly straight. Operculum large, but not filling aperture, nucleus terminal.

Radula: Typical for subfamily, rachidian tooth broad, excavated anteriorly, bearing four small cusps, the inner two slightly larger than the outer two. Lateral teeth large, tri-cuspid, cusps well-spaced, outer cusp strongly curved, inner cusp about half as long as outer, only slightly curved; central cusp slightly smaller than inner one, slightly curved.

Remarks: Differs from Laevisipho galaxaios in 1) brownish color, 2) smaller size, 3) less inflated whorls, and 4) occasional few, very faint spiral cords.

Etymology: The name honors the late Mr. Doyne W. Kessler, Fisheries biologist, NOAA/NMFS, Alaska Fisheries Science Center (retired). Mr. Kessler was the first to write a field guide to the fish and invertebrates of the Bering Sea and Gulf of Alaska, and was a friend and inspiration to the junior author in the study of Alaskan marine invertebrates.

Distribution: Central Aleutian Islands, from Atka Island, Andreanof Ids. (175°16 W) to near Seguam Island (172°17 W), at depths of 99– 220 m.

Habitat: Black sand and gravel bottoms, with bottom temperatures of 4.1–4.6°C.