Japonacteon, Taki, 1956

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 601

Genus JAPONACTEON Taki, 1956

Japonacteon Taki, 1956: 47 . Type species: Acteon nipponensis Yamakawa, 1911 [Pleistocene, Japan], by original designation.

DIAGNOSIS. — Shell morphology. Shell external, solid, oval, transversely sulcate; spire short. Aperture short and wide, anteriorly rounded. Inner lip slightly thickened. Columella with a small fold. Umbilicus closed. Operculum present.

Anatomy. Headshield with 2 posteriorly projecting lobes. Radula with a few lateral teeth. Radular teeth with a large, triangular base, a long cusp and normally several denticles.

REMARKS. — Taki (1956) characterized the genus Japonacteon as having a small radula, with only six lateral teeth, the teeth having a broad base and a denticulate cusp, and a headshield with only 2 posterior lobes. Subsequently Rudman (1971c) regarded Japonacteon as a valid genus, but argued that the morphology of the stomach and reproductive system are either very different from other Acteonidae or incorrectly described. The diagnosis above is based on Taki (1956).