Bathyacteon, Valdés, 2008

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 609

Genus BATHYACTEON n. gen.

Type species: Acteon aequatorialis Thiele, 1925 [Recent, southwest Indian Ocean].

DIAGNOSIS. — Shell morphology. Shell external, fragile, oval; spire short. Aperture longitudinal, anteriorly rounded. Inner lip thickened. Columella with a single fold. Operculum present.

Anatomy. Radular composed of a denticulate rachidian tooth and several lateral teeth with a broad base and numerous denticles.

REMARKS. — Bathyacteon is clearly different from other genera of Acteonidae based on its radular morphology. No other genera of Acteonidae have a denticulate rachidian tooth, with the exception of one species of Crenilabium Cossmann, 1889 (Marcus 1972; Bouchet 1975). Differences between Crenilabium and Bathyacteon include the very elongate shell and the more elongate lateral radular teeth of the former ( Bouchet 1975). Also, the rachidian tooth of Crenilabium exilis (Jeffreys, 1870) is a simple plate with no denticles, whereas in Bathyacteon it has several sharp denticles. Crenilabium pacificum described above lacks rachidian teeth. Other distinctive features of Bathyacteon include the wide and denticulate innermost lateral teeth and reduced shell sculpture. Other species described in this paper may belong to Bathyacteon but this cannot be confirmed because of the lack of anatomical information.