Acteocina voluta (Quoy & Gaimard, 1833)

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 706-709

Acteocina voluta (Quoy & Gaimard, 1833)

Figs 59A-D, 60A, B, 61

Bulla voluta Quoy & Gaimard, 1833 [in 1832-33]: 359-360, pl. 26, figs 33-35.

Synonym:

Tornatina sumatrana Thiele, 1925: 351 , pl. 32, fig. 3.

TYPE MATERIAL. — B. voluta : syntype MNHN 20838 . — T. sumatrana : not examined.

TYPE LOCALITY. — B. voluta : Guam. — T. sumatrana : Sumatra, Indonesia [ Valdivia ].

MATERIAL EXAMINED. — Indonesia. KARUBAR: stn DW 01 , 132°59’E, 206-210 m, 3 lv, 1 destroyed to dissect the radula and Kai Islands , 05°46’S, 132°10’E, 156-305 m, 3 dd (Figs 59C, D); gizzard plates (Figs 60A, B) .

stn DW 03, 05°48’S, 132°13’E, 278-301 m, 2 dd Fig. 59B); stn Loyalty Ridge. MUSORSTOM 6: stn DW 439, 20°46’S, 167°17’E, DW 15, 05°17’S, 132°41’E, 212-221 m, 2 dd; stn DW 18, 05°18’S, 288 m, 1 dd (Fig. 59A).

133°01’E, 205-212 m, 1 dd; stn DW 49, Tanimbar Islands, 08°00’S,

DISTRIBUTION. — Widespread Indo-Pacific species reported from Fiji, Guam, Torres Straits , Japan, Indonesia and the Gulf of Suez (see Marcus 1977). Specimens herein collected from the Kai Islands, Indonesia (Fig. 61), in 206- 288 m, live in 206-210 m.

FIG. 59. Shell morphology of species of Acteocina Gray, 1847 . A, Acteocina voluta (Quoy & Gaimard, 1833) , (12 mm), ventral view, New Caledonia, MUSORSTOM 6 stn DW 439; B, protoconch, KARUBAR stn DW 03, scale bar = 300 Μm; C, (14 mm), ventral view, Indonesia, KARUBAR stn DW 01; D, (4 mm), ventral view, Indonesia KARUBAR stn DW 03. E, Acteocina gracilis (A. Adams in Sowerby, 1850), (11 mm), ventral view, Tonga, BORDAU 2 stn DW 1612; F, same shell, protoconch, scale bar = 300 Μm. G, Acteocina lata n. sp., holotype MNHN 20350 (10 mm), ventral view, MUSORSTOM 8 stn DW 987.

FIG. 60. Anatomy and shell morphology of species of Acteocina Gray, 1847 and Truncacteocina Kuroda & Habe 1954 . A, Acteocina voluta (Quoy & Gaimard, 1833) , radula, Indonesia, KARUBAR stn DW 49, scale bar = 50 Μm; B, same specimen, gizzard plate, scale bar = 500 Μm. C, Acteocina gracilis (A. Adams in Sowerby, 1850), radula, New Caledonia, MUSORSTOM 4 stn CC 175, scale bar = 50 Μm; D, same specimen, gizzard plate, scale bar = 500 Μm. E, Acteocina sp. , 1.5 mm, ventral view, VAUBAN stn 40. F, Truncacteocina arata (Watson, 1883) , (5 mm), ventral view, MUSORSTOM 3 stn CP 101.

DESCRIPTION. — Shell morphology. Length 14 mm, width 5 mm (largest specimen examined). Shell solid, elongate, with almost parallel or slightly concave sides (Figs 59A, 59C). Juvenile shells oval, with more convex sides (Fig. 59D). Body whorl very large; spire variable in length, normally short, conical, with 2-4 whorls. Suture deeply canaliculate. Whorls with a conspicuous spiral keel near the base, absent in the body whorl. Protoconch flattened, about 1.5 whorls and 80 Μm in diameter (Fig. 59B); only attached to the teleoconch by the aperture. Umbilicus closed. Aperture very long, about 4/5 of the shell length, narrow, wider anteriorly, narrowing abruptly at about 1/5 of its length. Columellar margin thickened, oblique, with a long thick callus at its anterior end. Sculpture of fine spiral lines, crossed by faint axial lines, not visible in all specimens. Colour uniformly whitish to pale brownish.

Anatomy. The digestive system contains 3 smooth and irregular gizzard plates, all of them similar in shape and size (Fig. 60B). The radular formula is n x 1.0. 1 in a specimen from Indonesia (KARUBAR stn DW 49). The lateral teeth are hook-shaped with a number of small denticles on the single, curved cusp (Fig. 60A).

REMARKS. — Comparison of the material here examined with the syntype illustrated by Valdés & Héros (1998) confirmed that they belong to the same species. Both have elongate, smooth shells with the suture deeply channeled and the spire whorls with a conspicuous keel near the base.

Marcus (1977) redescribed this species, under the name Tornatina gaimardi (Finlay, 1927) , based on animals with three different shell morphologies collected in three different localities (Raoul Island in the Kermadec Islands, Sella Bay and Bile Bay in Guam). According to Marcus (1977) all these specimens had a similar anatomy so they were included in the same species. It is not clear whether these three specimens described by Marcus are A. voluta or why Marcus used the name Tornatina gaimardi . The specimens here examined show variation in shell morphology and sculpture, but in all cases the suture is channeled and the short spire whorls have a keel near the base.

Marcus (1977) also stated that the type material of Acteocina voluta was lost, and that Lemche designated a neotype for this species (no reference cited). I was unable to find any valid designation of a neotype for this species in the literature, and the original type material of A. voluta is deposited at MNHN (Valdés & Héros 1998).

Tornatina sumatrana , originally described from Sumatra, Indonesia, by Thiele (1925), also has a solid and elongate shell very similar to the remaining syntype of A. voluta and the material here examined.