Mauroceras sandwichense ( de Folin, 1881 )

Vannozzi, Angelo, 2023, The Caecidae from BIOMAGLO Expedition in the Mayotte-Glorieuses area (Mollusca, Gastropoda), Zoosystema 45 (12), pp. 421-434 : 431

Mauroceras sandwichense ( de Folin, 1881)

( Fig. 3N )

Meioceras sandwichensis [sic] de Folin, 1881: 18, pl. 1, figs 10, 11.

Mauroceras sandwichense — Vannozzi 2019a: 60 and synonymy therein.

TYPE MATERIAL. — Holotype. Hawaii • dd; Hawaii; MNHN-IM-2000-24904 figured by Pizzini et al. 2013: fig. 15G .

TYPE LOCALITY. — Pacific Ocean, Hawaii.

MATERIAL EXAMINED. — Mayotte • 1 dd juv; Mozambique Channel , W Mayotte, BIOMAGLO Stn DW4854; 12°56’S, 44°58’E; 455-465 m depth; 4.II.2017; MNHN .

DISTRIBUTION. — Indo-West Pacific, recorded from Red Sea, Mayotte and Hawaii ( Kay 1979; Blatterer 2019; Vannozzi 2019a).

DIAGNOSIS. — Shell small for the genus. Shell tubular, arched, slightly but clearly twisted in ventral view. Dorsal and ventral sides of the tube evenly arched. Septum slightly protruding, with a sharp dorsal mucro, slightly rotated toward the right side. Aperture simple, oblique. Early teleoconch coiled, trochospiral, widely umbilicated, starting to uncoil after about 1 whorl. Sculpture of slightly wavy collabral ribs in the early teleoconch, fading with teleoconch growth and disappearing in the adult stage. Transition to the adult stage rapid. Protoconch planorbid of 1. 5 whorls. Adult shell length 2 mm.

REMARKS

A single, rather worn juvenile stage was found in the examined material. This species shows a characteristically tightlycoiled early teleoconch that readily distinguishes it from the congeners ( Blatterer 2019; Vannozzi 2019a).

Figures

FIG. 3. — Side and ventral views of Caecum Fleming, 1813 and Mauroceras Vannozzi, 2019 species from BIOMAGLO expedition.: A, C. hyalinum Vannozzi, 2022 from Stn DW4847; B, C. egenum Vannozzi, 2017 from Stn DW4854; C, C. cf. mauritianum de Folin, 1868 from Stn DW4820; D, E, C. mauritianum; D, holotype MNHN-IM-2000-24911; E, paratype MNHN-IM-2000-24912; F-L, C. cooki Pizzini & Raines, 2011; F, specimen from Stn DW4847; G, H, specimens from Stn DW4854 (H, juv.); I-L, specimens from Stn DW4820; M, M. kajiyamai (Habe, 1963) from Stn DW4847; N, M. sandwichense (de Folin, 1881) juv.from Stn DW4854. Scale bar: 1 mm. Images D, E, courtesy of Ph. Maestrati (MNHN).