Caecum cooki Pizzini & Raines, 2011

(Fig. 3 F-L)

Caecum cooki Pizzini & Raines, 2011: 29, fig. 4A, B. — Pizzini et al. 2013: 35, fig. 14H-J.

TYPE MATERIAL. — Holotype. French Polynesia • dd;, Tuamotu Islands, Makemo, Arikitamiro Passage; MNHN-IM-2000-23124. Paratypes. French Polynesia • 1 dd; same data as for holotype; MNHN-IM-2000-23125 • 1 dd; Society Islands, Tahiti, Tiarei; fringing reef, shell grit; MNHN-IM-2000-23126 • 4 dd; Society Islands, W Moorea; 17°30’S, 149°46’W; 2-3 m depth; LACM 3131. Norhtern Mariana Islands • 6 dd; Saipan, Laolao Bay; 6-9 m depth; BR .

Indonesia • 1 dd; NW side of Lombok, off Ajer & Meno Islets; 8°22’S, 116°04’E; 5-20 m depth; rubble of steep coral slope; LACM 3130 .

TYPE LOCALITY. — Pacific Ocean, French Polynesia, Tuamotu, Makemo, Arikitamiro Passage.

MATERIAL EXAMINED. — Îles Éparses • 1 dd; Mozambique Channel, Banc du Geyser, BIOMAGLO Stn DW 4789; 12°22’S, 46°25’E; 340-342 m depth; 22.I.2017; MNHN.

Mayotte • 2 dd; Mozambique Channel, S Mayotte, BIOMAGLO Stn DW 4820; 13°05’S, 45°06’E; 295-336 m depth; 27.I.2017; MNHN • 1 dd; Mozambique Channel, S Mayotte, BIOMAGLO Stn DW 4826; 13°05’S, 45°07’E; 489-496 m depth; 27.I.2017; MNHN • 1 dd; Mozambique Channel, W Mayotte, BIOMAGLO Stn DW 4847; 12°41’S, 44°57’E; 738-763 m depth; 30.I.2017; MNHN • 1 dd; Mozambique Channel, NW Mayotte, BIOMAGLO Stn DW 4848; 12°35’S, 44°55’E; 399-402 m depth; 30.I.2017; MNHN • 1 dd; Mozambique Channel, SW Mayotte, BIOMAGLO Stn DW 4853; 13°00’S, 44°56’E; 665-669 m depth; 3.II.2017; MNHN • 2 dd (1 juv); Mozambique Channel, W Mayotte, BIOMAGLO Stn DW 4854; 12°56’S, 44°58’E; 455-465 m depth; 4.II.2017; MNHN • 1 dd; Mozambique Channel, SE Mayotte, BIOMAGLO Stn DW 4869; 12°58’S, 45°16’E; 917-1070 m depth; 07.II.2017; MNHN • 1 dd (growth stage); Mozambique Channel, NE Mayotte, BIOMAGLO Stn DW 4871; 12°44’S, 45°19’E; 462-486 m depth; 8.II.2017; MNHN .

DISTRIBUTION. — Indo-West Pacific, from the eastern coast of Africa (Kenya and Mayotte) to Maldives, Papua New Guinea, Philippines, New Caledonia and French Polynesia (Pizzini & Raines 2011; Pizzini et al. 2013; Vannozzi 2017; 2019b; unpublished data).

DIAGNOSIS. — Shell of average size for the genus. Tube smooth, tapering toward the apex. Aperture simple, inclined, preceded by a slight but distinct swelling on the ventral side. Microsculpture of fine longitudinal striae interrupted by growth lines. Macula small, white, heart-shaped. Septum protruding, with a strong, ear-like mucro rotated toward the right side. Juveniles thin, conical and curved, Transition to the adult stage rapid. Length about 2 mm.

REMARKS

This species shows a very wide distribution in the tropical Indo-West Pacific but is never abundant. A small heart-shaped white macula observed in the ventral side of the tube in adult shells is characteristic of this species.