Mauroceras rhinoceros ( Pizzini, Raines & Vannozzi, 2013 )

Walter, Angelo Vannozzi & Renda, Walter, 2024, Sampling the depth: New data on the Caecidae (Mollusca, Gastropoda) from northeastern Papua New Guinea, Zoosystema 46 (14), pp. 327-347 : 344

Mauroceras rhinoceros ( Pizzini, Raines & Vannozzi, 2013)

( Fig. 8D, E )

Meioceras rhinoceros Pizzini et al. 2013: 42 , fig. 16A-C.

Mauroceras rhinoceros – Vannozzi 2019b: 91, and synonymy therein.

TYPE MATERIAL. — Holotype. Loyalty • sh; Lifou , Baie de Santal , NE of the Bay, level of Cila, 25-30 m depth; MNHN-IM-2000-24880 . Paratypes. Loyalty • 1 sh; same data as for holotype; MNHN-IM-2000-24881 .

Papua New Guinea • 2 sh; New Britain, Rabaul , 4°12’S, 152°11’E; AMS C044117-n. 003958B .

Indonesia • 1 sh; N Sulawesi, off Menado , S side of Bunaken and Siladen ; 1°36.2’N, 124°46’E; 5-20 m depth; LACM 88-55 • 1 sh; Gulf of Tomini , Kep.Togian, Batudaka Is. , 12-17 m depth; coll. IK .

TYPE LOCALITY. — Pacific Ocean, Loyalty, Lifou, Baie de Santal, NE of the Bay, level of Cila, 25-30 m depth.

MATERIAL EXAMINED. — Papua New Guinea • 1 sh; New Ireland; 2°45’S, 150°37’E; 163-358 m depth; 3.IX.2014; KAVIENG 2014 Stn DW4470; MNHN .

DISTRIBUTION. — Indonesia, North Sulawesi, Philippines, northeastern PNG ( Pizzini et al. 2013; Vannozzi 2017, 2019a, b, unpublished data).

DIAGNOSIS. — Shell very large for the genus, whitish, glossy. Protoconch planorbid, smooth, of 1.75 whorls, ending with thickened sinusigera lip.Teleoconch almost straight, tubular. Early teleoconch conical, rapidly growing, with hardly visible annular sculpture. Adult shell subcylindrical, tapering toward both the apex and the aperture. Maximum width located adapically at about ¼ of the length. Septum recessed below the cutting plane, with a strong hook-like mucro projecting well beyond the cutting plane. Aperture oblique, simple with reflected lip. Operculum and soft parts unknown. Adult shell length c. 6 mm, protoconch size 280 µm.

REMARKS

This huge species can be considered as the giant of the family. Due to its peculiar characters and the large size, it is easily identified.

Figures

FIG. 8. — Mauroceras Vannozzi, 2019 species from deep-water stations from northeastern PNG: A, B, M. kajiyamai (Habe, 1963) from Stn CP3680 (B, juvenile); C, M. kajiyamai from Stn DW4465; D, E, M. rhinoceros (Pizzini, Raines & Vannozzi,2013) from Stn DW4470; F, G, M. serratum (Vannozzi, 2017) from Stn DW4465 (G, growth stage). Scale bar: 1 mm.