Pupa nitidula (Lamarck, 1822)

(Figs. 2D, 4C, 5C, 6C, 7C, 8C, 10)

Tornatella nitidula Lamarck, 1822: 221. Type locality: Île-de-France [= Mauritius].

Type material Tornatella nitidula — 5 syntypes, dry shells, 10.4–19.1 mm long (MHNG Moll-51412), two of them illustrated by Mermod (1963: fig. 220).

Material examined. Rat Island, Koumac, New Caledonia (20°35.1′S, 164°07.6′E), 14 m depth [Koumac 2.1 stn. KR640, soft bottom], 28 Sep 2018, 1 specimen 15 mm long (shell) (MNHN IM-2013-86157, isolate KF67).

Double Island, Koumac, New Caledonia (20°28′S, 164°07.6′E), 0 m depth [Koumac 2.1 stn. KM309, sand-mud flat with dead corals and seagrass], 17 Sep 2018, 1 specimen 14 mm long (shell) (MNHN IM-2013-86156, isolate KF66). Plateau Karembé, north end, Koumac, New Caledonia (20°37.6′S, 164°17.3′E), 0 m depth [Koumac 2.1 stn. KM301, coral blocks, sand, mud], 8 Sep 2018, preserved in RNAlater and destroyed (isolate KF24)

External morphology. Body short, protruding slightly beyond the shell, flattened anteriorly (Fig. 2D). Cephalic shield bilobed, with two elongate, tentacular-like lateral extensions, two posterior extensions covering anterior end of shell. Foot extending beyond cephalic shield and shell laterally. Body color translucent white, with numerous minute opaque white dots scattered all over dorsal surface of cephalic shield, foot. Shell solid, oval, widest mid-length, with convex sides, rounded anterior end (Fig. 10). Body whorl large, about 7/8–8/9 of total length. Spire short, conical, with 3–4 whorls. Suture channeled.Aperture elongate, wider anteriorly, narrowing gradually towards posterior end, ending at 1/4–1/8 of the posterior end of first whorl. Columellar margin thickened, oblique, with very conspicuous anterior fold, thickened centrally, starting at anterior end of aperture; minute, simple posterior fold located about aperture mid-length, separated from anterior fold by short gap. Apex of all specimens examined damaged, protoconch not observed. Sculpture composed of few irregular spiral grooves on the anterior end of body whorl. Grooves separated by gaps of variable width. Shell color pinkish-brown to dark brown, darker towards anterior and posterior ends of body whorl, lacking distinct patches. Posterior whorls either same color as body whorl or white. Operculum translucent, elongate, with faint transverse striations (Fig. 4C).

Internal morphology. Reproductive system with short, oval penis, composed of wide sheath, distinct conical tip (Fig. 5C). Digestive system with elongate buccal mass (Fig. 6C). Oral tube conical, connected to long, convoluted buccal bulb. Elongate salivary glands, esophagus, connected subapically on proximal end of buccal bulb. Radular formula 61 × 5.0. 5 in a 15 mm long specimen (MNHN IM- 2013-86157). Three innermost lateral teeth similar in shape, increasing in size gradually outward (Fig. 7C). Teeth triangular, with broad base; large, elongate, curved, sharp cusp; 2–6 denticles similar to cusp in shape, much smaller. Two outermost lateral teeth hook-shaped, with single large cusp, lacking denticles. Jaws with short, wide elements, bearing 10–16 finger-like projections apically, all on same plane (Fig. 8C).

Geographic range. Widespread in the tropical Indo-West Pacific region (Rudman, 2000; Gosliner et al., 2018).

Remarks. Lamarck (1822) described Tornatella nitidula with a brief text and a reference to an illustration in Bruguière (1798 –1816 [1816]: pl. 452, figs. 2a, b). Lamarck (1822) characterized this species as having two columellar folds, the lower [=anterior] one larger.The specimen illustrated has a short spire and very strong columellar folds, consistent with the current usage of the name Pupa nitidula. Subsequent illustrations of this species by Kiener (1834: pl. 1, fig. 5) and Reeve (1842b: pl. 206, fig. 5) clearly represent the same species and are consistent with the illustrations of two syntypes in Mermod (1963: fig. 220). The specimens here examined are also consistent with the original description and photographs of the syntypes and are confidently assigned to this species.