Shell medium in size (between 93.9 and 131.4 mm), thin but solid. Shape rather elongate with slender spire and oval body whorl. Spiral sculpture dominant. Colour white to pink with darker base, red brown spiral cords and a red brown subsutural spiral band. Protoconch decollate in all studied specimens.
Teleoconch with 5 or 6 angulate whorls. Upper whorls sculptured with 2 sharp primary spiral cords, interspaces broad, smooth. Subsutural slope broad, slightly convex, smooth or with some broad, flattened secondary spiral cords of which 1 is occasionally stronger. Body whorl with 8 or 9 primary spiral cords, two adapical ones strong, weaker on base. Interspaces smooth or with 1, 5 or 7 broad, flattened secondary spiral cords, central one slightly stronger. Interspaces gradually becoming narrower towards base. Axial sculpture consisting of a few fine incremental lines. Aperture ovate, white. Outer lip thin, slightly angulate when following shape of spiral cords. Columella smooth, gently twisted, callus thin. Siphonal canal short, broad, wide open. Operculum corneous, thick, dark brown, nucleus terminal.

Neptunea alexeyevi n. sp. has a characteristic sculpture of sharp primary spiral cords with broad interspaces and a broad, slightly convex subsutural slope. The species is rather variable in shape (slender with elongate spire or broad), presence or absence of secondary spiral cords in the interspaces and on subsutural slope. It is usually the slender form which has smooth interspaces and it is usually the broad form which has some fine secondary spiral cords (and a secondary spiral cord on the subsutural slope).
But this is not a rule and sufficient intermediate combinations are found to prove that both forms fit well within the infrasubspecific variability of the species. Both forms are not found together and we may conclude that they are ecophenotypes. Neptunea lyrata differs in having a larger number of primary spiral cords which arc broader, interspaces which are equal in size, a narrower subsutural slope and usually a glossier shell.
Etymology: Neptunea alexeyevi n. sp. is named to honour our dear friend Dmitry Alexeyev (Federal Research Institute of Fisheries and Oceanography, VNIRO, Moscow) for his contributions to the knowledge of the northern Pacific malacofauna.

Neptunea alexeyevi n. sp. is a high-boreal to Arctic species, living in the northwestern Bering Sea and known from off Cape Navarin and from Natalia Bay. Bathymetric range between 80 and 270 m. Living on sand. Neptunea specimens from Newfoundland in the Dautzenberg collection (KBIN,
Belgium) are similar but we have not seen additional material (see Text Fig. 29). Fossil evidence from the northern coast of Canada has not been collected yet. If and when these Atlantic shells are confirmed as belonging to this species, the range of the species has to be extended to the east. Type material:
Holotype: 115.7 mm, Bering Sea, southeast off Cape Navarin