Acteon, Montfort, 1810

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 638

“ Acteon ” sp. 8

Figs 22H, 23

MATERIAL EXAMINED. — New Caledonia proper. BATHUS 4 : stn DW 885 , Passe de St Vincent , 22°05’S, 165°58’E, 250-300 m, 1 dd .

DISTRIBUTION. — Single shell collected from New Caledonia (Fig. 23), in 250-300 m.

DESCRIPTION. — Shell morphology. Length 9 mm, width 5 mm (single specimen examined). Shell solid, wide, with convex sides (Fig. 22H). Body whorl large, about 2/3 of the shell length. Spire elongate, conical, with 4 whorls. Suture channeled. Umbilicus narrow and partially covered by an extension of the columellar margin. Aperture short and wide, wider anteriorly and narrowing abruptly at about 1/2 its length. The aperture is about 3/4 of the body whorl length. Columellar margin thickened, slightly oblique, with a simple fold. Sculpture of a number of punctuated spiral grooves. The punctuations are large, oval, almost square, fused to the next one within each groove. The grooves are separated by gaps that are as wide or slightly narrower than the grooves. Colour uniform pale grey.

Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — “ Acteon ” sp. 8 has a very similar sculpture and spire to Maxacteon kawamurai but differs from it in having a wider and shorter body whorl and aperture. It may be a teratological form of M. kawamurai but since no anatomical information is available a definitive conclusion is not possible. Therefore “ Acteon ” sp. 8 is here maintained as a distinct species until more material becomes available.

A definitive generic placement for this species is not possible until complete specimens become available for study.