Caecum neocaledonicum de Folin, 1868

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 : 338

Caecum neocaledonicum de Folin, 1868

( Fig. 6G, H )

Caecum neo-caledonicum de Folin, 1868a: 57 , pl. 6, figs 1, 2.

Caecum neocaledonicum – Vannozzi 2019b: 76, fig 7B and synonymy therein.

TYPE MATERIAL. — Lectotype. New Caledonia • sh; Nouméa ; MNHN-IM-2000-24909 .

Paralectotypes. New Caledonia • 22 sh; same data as for lectotype; MNHN-IM-2000-24910 .

TYPE LOCALITY. — Pacific Ocean, New Caledonia, Nouméa.

MATERIAL EXAMINED. — Papua New Guinea • 1 sh (juv); New Ireland; 2°44’S, 150°35’E; 240-305 m depth; 3.IX.2014; KAVIENG 2014 Stn DW4463; MNHN • 2 sh (juv); New Ireland; 2°43’S, 150°36’E; 140-214 m depth; 3.IX2014; KAVIENG 2014 Stn DW4464; MNHN • 1 sh; New Ireland; 2°45’S, 150°37’E; 163- 358 m depth; 3.IX.2014; KAVIENG 2014 Stn DW4470; MNHN .

DISTRIBUTION. — The whole IWP, from the Red Sea and east coast of Africa to Japan and French Polynesia ( Hasegawa 2000; Pizzini & Raines 2011; Pizzini et al. 2013; Vannozzi 2017, 2019b, 2022b; Blatterer 2019).

DIAGNOSIS. — Shell small to large for the genus, white, solid but not very thick, wide. Protoconch planorbid, multispiral of 1.75 whorls. Teleoconch tubular, arched. Early teleoconch conical, then subcylindrical, smooth. Adult shell subcylindrical, with few strong rings close to the aperture. Septum protruding, dome-shaped with a clear marginal mucro rotated toward the right side. Microsculpture of conspicuous wavy longitudinal furrows. Periostracum light brownish. Operculum thick, flat. Animal described by Vannozzi (2019b). Adult shell length in the range 1.5-4 mm, protoconch diameter 310 µm.

REMARKS

Caecum neocaledonicum is easily distinguished notwithstanding the variability shown during shell ontogeny by the relatively wide tube and the presence of the longitudinal microsculpture (Pizzini 1998). The few specimens examined from northeastern PNG are remarkable due to their small size. However, no other differences with respect to specimens from other IWP localities could be observed.

Figures

FIG. 6. — Caecum Fleming, 1813 species from deep-water stations from northeastern PNG: A-D, C. dakuwaqa Pizzini, Raines & Vannozzi, 2013 from Stn DW4470 (C, D: juvenile); E, C. dakuwaqa from Stn DW4463; F, C. cf. succineum from Stn DW4495; G, C. neocaledonicum de Folin, 1868 from Stn DW4470; H, C. neocaledonicum from Stn DW4464; I, C. frugi Vannozzi, 2019 from Stn DW4412; J, C. frugi juv. from Stn CP4418; K, C. neoguineanum Vannozzi, 2019 from Stn DW4495; L, C. sp. from Stn DW4465 MNHN-IM-2022-2399. Scale bars: A-H, K, L, 1 mm; I, J, 0.5 mm.