Caecum vertebrale Hedley, 1899

(Fig. 2 E-H)

Caecum vertebrale Hedley, 1899: 425, fig. 15. — Vannozzi 2019b: 74 and synonymy therein.

TYPE MATERIAL. — Holotype. Tuvalu • sh; Funafuti Atoll; AMS n. C5917.

TYPE LOCALITY. — Pacific Ocean, Tuvalu, Funafuti Atoll.

MATERIAL EXAMINED. — Papua New Guinea • 1 sh; Off Bougainville; 5°02’S, 154°29’E; 615-632 m depth; 13.X.2010; BIOPAPUA Stn DW3754; MNHN • 1 sh; New Ireland; 2°24’S, 149°55’E; 272-274 m depth; 6.IX.2014; KAVIENG 2014 Stn DW4495; MNHN • 1 sh; Bagabag Island; 4°44’S, 146°12’E; 480-490 m depth; 5.XII.2012; PAPUA NIUGINI Stn DW3977; MNHN .

DISTRIBUTION. — Philippines, northeastern PNG, Japan, New Caledonia, Loyalty, Vanuatu, Society, Tuvalu (Hedley 1899; Pizzini et al. 2013; Hasegawa 2000; Vannozzi 2017, 2019b).

DIAGNOSIS. — Shell of average size for the genus, colourless, semitransparent. Protoconch unknown.Teleoconch tubular, arched, with strong collabral rings. Early teleoconch conical, smooth with rings gradually appearing and increasing in strength during the growth. Adult shell cylindrical, evenly arched. Sculpture of c. 25 strong, rounded rings. Aperture simple, edged by two paired rings. Septum dome-shaped without mucro, sometimes encrusted. Animal described by Vannozzi (2019b). Adult shell length c. 2.5 mm.

REMARKS

A few rather worn specimens were examined, all of them showing unusual septa. One of them shows a unique hemispherical mucro positioned in the middle of the septum. However, the other examined specimens show irregular shapes. Occasionally, the septum in C. vertebrale shows irregular shapes (Pizzini et al. 2013: fig. 8K, M), therefore we attribute no specific value to the peculiar shape shown in Figure 2 E-H.