Caecum musorstomi 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 : 333-334

Caecum musorstomi Pizzini, Raines & Vannozzi, 2013

( Fig. 3F )

Caecum musorstomi Pizzini, Raines & Vannozzi, 2013: 27 , figs 12G-I, 19F. — Vannozzi 2019b: 86, fig. 4J-N and synonymy therein.

TYPE MATERIAL. — Holotype. New Caledonia • lv; Nouméa Sector SW, Larégnère reef, inner slope; 22°19.9’S, 166°17.6’/ 166°16.1’E; 12-16 m depth; 3.V.1993; MNHN-IM-2000-24921 .

Paratypes. New Caledonia • 1 lv, 5 sh, 1 juv., 1 sh broken; same data as for holotype; MNHN-IM-2000-24922 • 1 lv; Nouméa Sector SW, Platier îlot Maître , MONTROUZIER Stn 1351; 22°20’23”N, 166°25’41”E; 0-1 m depth; 25.XI.1992; MNHN-IM-2000-24923 • 1 lv; Nouméa Sector , Pointe Magnin, MONTROUZIER Stn 1355; 22°18’54”N, 166°26’35”E; 7-10 m depth; 3.XII.1992; MNHN-IM-2000-24924 • 1 lv, 17 sh; Cap Woodin , LAGON Stn DW1233; 22°23’34”N, 166°47’39”E; 45- 50 m depth; 9.III.1993; MNHN-IM-2000-24925 • 9 sh; Touho sector, Channel NE of Banc de Touho , MONTROUZIER Stn 1260; 20°43’59”N, 165°13’59”E; 49-50 m depth; 1-30.IX.1993; MNHN-IM-2000-24926 • 2 sh; Touho sector, Touho Channel, MONTROUZIER Stn 1261; 20°46’59”N, 165°16’30”E; 45-56 m depth; 1-30.IX.1993; MNHN-IM-2000-24927 • 2 sh; Touho sec - tor, Grand Reef Mangalia Lagoon, MONTROUZIER Stn 1264; 20°44’30”N, 165°15’53”E; 8 m depth; 1-30.IX.1993; MNHN-IM-2000-24928 • 1 sh; Touho sector, Grand Reef Mangalia Lagoon, MONTROUZIER Stn 1266; 20°39’36”N, 165°14’42”E; 10-15 m depth; 1-30.IX.1993; MNHN-IM-2000-24929 • Koumac sector, Koumac bay, MONTROUZIER Stn 1277; 20°34’0”N, 164°16’0”E; 0-2 m depth; 1-31.X.1993; MNHN-IM-2000-24520 • 1 sh; Koumac sector, Rat Island, MONTROUZIER Stn 1284; 20°33’42”N, 164°10’59”E; 0-1 m depth; 1-31.X.1993; MNHN-IM-2000-24521 • 1 sh; Koumac sector, Paagoumène, MONTROUZIER Stn 1289; 20°29’12”N, 164°10’11”E; 0-1 m depth; 1-31.X.1993; MNHN-IM-2000-25159 • 1 lv; Koumac sector, Paagoumène, MONTROUZIER Stn 1289; 20°29’12”N, 164°10’11”E; 0-1 m depth; 1-31.X.1993; M. Pizzini collection • 1 lv, 1 sh; Koumac sector, Babouillat Point, MONTROUZIER Stn 1292; 20°22’23”N, 164°6’47”E; 0-1 m depth; 1-31.X.1993; MNHN-IM-2000-24522 • 2 lv, 2 sh; Koumac sector, Lagoon between earth and the Infernet, MONTROUZIER Stn 1299; 20°34’23”N, 164°13’0”E °S; 12-14 m depth; 1.X.1993 / 31.X.1993; MNHN-IM-2000-24523 • 2 lv; Koumac sector, areas of the Karembé Plateau, MONTROUZIER Stn 1303; 20°38’48”N, 164°17’5”E; 0-8 m depth; 1-31.X.1993; MNHN-IM-2000-24524 • 1 sh; Koumac sector, Great Koumac Reef, KOUMAC Stn 1331; 20°40’36”N, 164°12’6”E; 55-57 m depth; 31.X.1993; MNHN-IM-2000-24525 .

Vanuatu • 1 sh; E Aoré Island , Mambeto Point , SANTO 2006 Stn DB08; 15°34’37”N, 167°13’46”E; 12 m depth; 12.IX.2006; MNHN-IM-2000-24526 • 8 lv, 13 sh; S Aoré Island , SW Port Lautour, SANTO 2006 Stn DB12; 15°36’38”N, 167°10’3”E; 10- 18 m depth; 13.IX.2006; MNHN-IM-2000-24527 • 1 lv, 2 sh; E Louganville, Between Wharf E Unity Park & Customs , SANTO 2006 Stn DB14; 15°30’53”N, 167°11’0”E; 10-14 m depth; 13.IX.2006; MNHN-IM-2000-24528 • 1 sh; NW Urélapa Island , SANTO 2006 Stn DB20; 15°36’30”N, 167°1’21”E; 22-25 m depth; 15.IX.2006; MNHN-IM-2000-24529 • 2 sh; Palikulo Bay , Old Japanese Fisheries , SANTO 2006 Stn DB40; 15°28’48”N, 167°15’9”E; 5 m depth; 19.IX.2006; MNHN-IM-2000-24530 • 3 sh; NW Aésé Island , Palikulo Bay, SANTO 2006 Stn DB69; 15°24’23”N, 167°13’2”E; 38 m depth; 27.IX.2006; MNHN-IM-2000-24532 • 3 sh; Palikulo Bay , E Cape Undine, SANTO 2006 Stn DS43; 15°27’54”N, 167°14’16”E; 22 m depth; 20.IX.2006; MNHN-IM-2000-24533 • 2 sh; E Palikulo Bay , W Old Japanese Fisheries-Wharf , SANTO 2006 Stn DS54; 15°28’48”N, 167°15’9”E; 5 m depth; 22.IX.2006; MNHN-IM-2000-24534 • 1 sh; S Oyester Island, Outer reef, SANTO 2006 Stn FB40; 15°22’55”N, 167°11’42”E; 9 m depth; 29.IX.2006; MNHN-IM-2000-24535 • 5 lv, 2 sh; SE Malo Island , W Malokilikili Island, SANTO 2006 Stn FB52; 15°42’42”N, 167°15’15”E; 7 m depth; 5.X.2006; MNHN-IM-2000-24536 • 1 lv; E Aoré Island, S Port Benier Bay , SANTO 2006 Stn FB61; 15°34’23”N, 167°12’36”E; 2-3 m depth; 9.X.2006; MNHN-IM-2000-24537 • 1 sh; Tutuba Island , Vanatovoa Bay, SANTO 2006 Stn FB92; 15°33’35”N, 167°16’33”E; 2-4 m depth; 14.X.2006; MNHN-IM-2000-24538 • 1 sh; Matewulu Beach , N Matafou River Mouth , SANTO 2006 Stn LD09; 15°22’10”N, 167°11’17”E; 2-3 m depth; 14.X.2006; MNHN-IM-2000-24539 • 2 sh; Strait N Tangoa Island, SANTO 2006 Stn LD29; 15°35’17”N, 167°59’24”E; 10-12 m depth; 13.X.2006; MNHN-IM-2000-24540 • 2 sh; Segond Channel , Sakara River Mouth , SANTO 2006 Stn LS17; 15°31’4”N, 167°10’30”E; 7 m depth; 14.X.2006; MNHN-IM-2000-24541 • 1 sh; Segond Channel, Off Maritime College, SANTO 2006 Stn NS36; 15°31’39”N, 167°9’31”E; 2-3; 02.X.2006; MNHN-IM-2000-24542 • 1 sh; Segond Channel , Beach Front Maritime College , SANTO 2006 Stn NS37; 15°31’21”N, 167°9’46”E; 2-3 m depth; 02.X.2006; MNHN-IM-2000-24543 • 1 lv; Segond Channel , NW Aoré Island , SANTO 2006 Stn NB12; 15°33’31”N, 167°9’37”E; 20 m depth; 19.IX.2006; MNHN-IM-2000-24544 • 2 sh; E Aoré Island , Ambuei Bay, SANTO 2006 Stn ZB16; 15°32’23”N, 167°12’8”E; 5 m depth; 17.X.2006; MNHN-IM-2000-24545 .

TYPE LOCALITY. — Pacific Ocean, New Caledonia, Nouméa Sector SW, Larégnère reef, 22°19.9’S, 166°17.6’E / 166°16.1’E, inner slope, 12-16 m depth.

MATERIAL EXAMINED. — Papua New Guinea • 1 sh (gs); New Ireland; 2°33’S, 150°40’E; 500-600 m depth; 27.VIII.2014; KAVIENG 2014 Stn DW4412; MNHN .

DISTRIBUTION. — Thailand, Philippines, northeastern PNG, New Caledonia, Vanuatu ( Pizzini et al. 2013; Vannozzi 2017, 2019b, unpublished data).

DIAGNOSIS. — Shell of average size for the genus, colourless, semitransparent. Protoconch unknown. Teleoconch tubular, slightly arched, with fine collabral rings. Early teleoconch slender, subcylindrical. Adult shell slender, cylindrical, evenly arched. Sculpture of fine rings, best visible toward the aperture. Aperture preceded by a well-developed swelling crossed by small rings. Longitudinal microsculpture present. Septum slightly protruding with a rounded mucro rotated toward the right side. Periostracum light brownish. Operculum thin, flat. Soft parts unknown. Adult shell length c. 2 mm.

REMARKS

Caecum musorstomi is a widespread species and occurs frequently. It shows rather constant characters and is usually easily identified. Only a single specimen was found in the examined material. This specimen is a short form, showing a length which is half the usual adult shell length. Short specimens are known from several species and are regarded as transitional growth stages ( Pizzini et al. 1995; Lee unpublished).

Figures

FIG. 3. — Caecum Fleming,1813 species from deep-water stations from northeastern PNG:A-D, Caecum microannulatum n. sp., holotype MNHN-IM-2000-38948; E, C. microannulatum n. sp., juvenile from type locality; F, C. musorstomi Pizzini, Raines & Vannozzi, 2013 from Stn DW4412, transitional growth stage. Scale bar: 1 mm, details not to scale.