Ethalia montrouzieri (Souverbie, 1859)

Figs 8–12

Rotella montrouzieri Souverbie, 1859: 376 . Type locality: “ Insula Art ”, Belep, New Caledonia.

Rotella montrouzieri – Souverbie 1860: 123, pl. 2 fig. 11. — Fischer 1878: 207; 1879 in 1875–1880: 379. — Herbert 1996: 412, figs 3–5 (holotype).

Ethalia guamensis var. montrouzieri – Pilsbry 1889 –1890: 459, pl. 59 fig. 37.

Ethalia guamensis montrouzieri – Kaicher 1990: 5700.

Ethalia montrouzieri – Hickman & McLean 1990: 127, fig. 82c [?= E. catharinae]. — Héros et al. 2007: 209.

Material examined

Holotype (Fig. 8A–D) NEW CALEDONIA • Belep, Île Art; MHNBx 2004.TY.126 .

Other material

NEW CALEDONIA – Plateau Chesterfield-Bellona • 1 specimen, dead; Plateau des Chesterfield, Stn DW72; 19°15′ S, 158°21′ E; depth 32 m; 25 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 3 specimens, dead; Plateau des Chesterfield, Stn DW44; 19°22′ S, 158°23′ E; depth 40 m; 23 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 2 specimens, dead; Plateau des Chesterfield, Stn DW128; 19°28′ S, 158°30′ E; depth 38 m; 29 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 1 specimen, dead; Plateau des Chesterfield, Stn DW41; 19°22′ S, 158°32′ E; depth 52 m; 23 Jul. 1988; NO Coriolis - CORAIL 2 leg.; MNHN • 1 specimen, dead; Plateau des Chesterfield, Stn DW117; 19°25′ S, 158°32′ E; depth 52 m; 28 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 1 specimen, living; Plateau des Chesterfield, Stn DW38; 19°22′ S, 158°43′ E; depth 61 m; 23 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 7 specimens, dead; Plateau des Chesterfield, Stn DW110; 19°09′ S, 158°56′ E; depth 40 m; 28 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 2 specimens, dead; Plateau des Chesterfield, Stn DW60; 19°15′ S, 158°57′ E; depth 45 m; 24 Jul. 1988; NO Coriolis -CORAIL 2 leg.; MNHN • 8 specimens, living; Plateau Chesterfield-Bellona, Stn D54; 21°25.9′ S, 158°59.5′ E; depth 36–42 m; Jul. 1984; CHALCAL 1 leg.; MNHN • 1 specimen, living; Plateau Chesterfield-Bellona, Stn D60; 21°48.65′ S, 159°27.95′ E; depth 45 m; Jul. 1984; CHALCAL 1 leg.; MNHN • 8 specimens, living; Plateau Chesterfield-Bellona; no coordinates; no depth; 1984; CHALCAL 1 leg.; MNHN. – d’Entrecasteaux Reefs – Lagon Nord – Belep • 3 specimens, living; Atoll de Huon, Stn 438; 18°10′ S, 162°51′ E; depth 37 m; 25 Feb. 1985; B. Richer-ORSTOM leg.; MNHN • 6 specimens, living; Atoll de Surprise, Stn 445; 18°18′ S, 163°02′ E; depth 41 m; 28 Feb. 1985; B. Richer-ORSTOM leg.; MNHN • 3 specimens, dead; Atoll de Surprise, Stn 473; 18°24′ S, 163°03′ E; depth 50 m; 1 Mar. 1985; B. RicherORSTOM leg.; MNHN • 3 specimens, dead; Atoll de Surprise, Stn 465; 18°22′ S, 163°05′ E; depth 45 m; 1 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Atoll de Surprise, Stn 466; 18°24′ S, 163°07′ E; depth 42 m; 1 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 6 specimens, dead; Atoll de Surprise, Stn 471; 18°28′ S, 163°07′ E; depth 42 m; 1 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 5 specimens, dead; Stn 1158; 19°10′ S, 163°07′ E; depth 48 m; 30 Oct. 1989; B. RicherORSTOM leg.; MNHN • 5 specimens, living; Stn 1168; 19°16′ S, 163°09′ E; depth 50 m; 30 Oct. 1989; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 1157; 19°10′ S, 163°10′ E; depth 48 m; 30 Oct. 1989; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Lagon Nord, Stn 542; 19°06′ S, 163°10′ E; depth 50 m; 6 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn 1169; 19°19′ S, 163°11′ E; depth 47 m; 30 Oct. 1989; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Lagon Nord, Stn 541; 19°06′ S, 163°13′ E; depth 45 m; 6 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 1170; 19°18′ S, 163°14′ E; depth 65 m; 30 Oct. 1989; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 1197; 19°36′ S, 163°22′ E; depth 41 m; 1 Nov. 1989; B. Richer-ORSTOM leg.; MNHN • 4 specimens, dead; Lagon Nord, Stn 536; 19°09′ S, 163°23′ E; depth 61 m; 6 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Lagon Nord, Stn 535; 19°11′ S, 163°25′ E; depth 46 m; 6 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 1205; 19°42′ S, 163°26′ E; depth 38 m; 2 Nov. 1989; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Lagon Nord, Stn 478; 18°53′ S, 163°27′ E; depth 37 m; 2 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Lagon Nord, Stn 479; 18°55′ S, 163°28′ E; depth 37 m; 2 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Lagon Nord, Stn 482; 18°59′ S, 163°31′ E; depth 33 m; 2 Mar. 1985; B. RicherORSTOM leg.; MNHN • 2 specimens, living; Lagon Nord, Stn 481; 18°57′ S, 163°32′ E; depth 50 m; 2 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Lagon Nord, Stn 485; 18°58′ S, 163°33′ E; depth 32 m; 2 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Stn 1213; 19°50′ S, 163°33′ E; depth 32 m; 3 Nov. 1989; B. Richer-ORSTOM leg.; MNHN • 7 specimens, dead; Lagon Nord, Stn 519; 19°02′ S, 163°34′ E; depth 39 m; 5 Mar. 1985; B. Richer-ORSTOM leg.; MNHN • 5 specimens, living; Stn 1217; 19°52′ S, 163°36′ E; depth 30 m; 3 Nov. 1989; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn 1118; 19°35′ S, 163°52′ E; depth 30 m; 25 Oct. 1989; B. RicherORSTOM leg.; MNHN • 1 specimen, dead; Stn 1105; 19°40′ S, 163°57′ E; depth 25 m; 25 Oct. 1989; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 1104; 19°42′ S, 163°59′ E; depth 22 m; 25 Oct. 1989; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Balabio Island • 1 specimen, dead; Stn 1046; 20°05′ S, 164°07′ E; depth 6–7 m; 4 May 1988; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Poum • 2 specimens, dead; Stn 1016; 20°09′ S, 163°49′ E; depth 19–20 m; 3 May 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 1017; 20°08′ S, 163°51′ E; depth 21 m; 3 May 1988; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn 1015; 20°10′ S, 163°52′ E; depth 25 m; 3 May 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 1007; 20°12′ S, 163°52′ E; depth 23–24 m; 2 May 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 1008; 20°11′ S, 163°53′ E; depth 27 m; 2 May 1988; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn 984; 20°21′ S, 163°56′ E; depth 21–23 m; 30 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 989; 20°18′ S, 163°57′ E; depth 21 m; 30 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 9 specimens, living; Stn 982; 20°22′ S, 163°59′ E; depth 34–48 m; 29 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 971; 20°26′ S, 164°00′ E; depth 25–26 m; 29 Apr. 1988; B. RicherORSTOM leg.; MNHN • 1 specimen, living; Stn 961; 20°29′ S, 164°02′ E; depth 19–20 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Pouébo • 1 specimen, dead; Stn 901; 20°13′ S, 164°22′ E; depth 22–40 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 5 specimens, living; Stn 898; 20°14′ S, 164°27′ E; depth 22 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 3 specimens, dead; Stn 895; 20°16′ S, 164°27′ E; depth 16 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn 896; 20°15′ S, 164°29′ E; depth 20 m; 14 Jan. 1987; B. RicherORSTOM leg.; MNHN • 4 specimens, living; Stn 892; 20°18′ S, 164°32′ E; depth 26 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 6 specimens, living; Stn 891; 20°20′ S, 164°34′ E; depth 25 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 4 specimens, living; Stn 890; 20°20′ S, 164°36′ E; depth 23 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 6 specimens, living; Stn 888; 20°22′ S, 164°38′ E; depth 20 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn 885; 20°26′ S, 164°42′ E; depth 32 m; 14 Jan. 1987; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Koumac • 2 specimens, living; Stn 954; 20°31′ S, 164°03′ E; depth 15–17 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn KD537; 20°31′ S, 164°03.3′ E; depth 12 m; 6 Nov. 2019; KOUMAC 2.3 leg.; sable blanc, éponges; DNA voucher, photographed alive (image LC349); MNHN IM-2019-7682 • 1 specimen, living; Stn KD533; 20°32.2′ S, 164°05.5′ E; depth 11 m; 5 Nov. 2019; KOUMAC 2.3 leg.; sable blanc nu; MNHN • 1 specimen, living; Stn KD565; 20°32.9′ S, 164°05.7′ E; depth 3 m; 15 Nov. 2019; KOUMAC 2.3 leg.; sable blanc et algues vertes filamenteuses et cotoneuses; MNHN • 1 specimen; Stn 953; 20°32′ S, 164°06′ E; depth 18–19 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 10 specimens, living; Stn KD563; 20°33.4′ S, 164°06.3′ E; depth 5 m; 15 Nov. 2019; KOUMAC 2.3 leg.; sable blanc; MNHN • 5 specimens, living; Pointe de Babouillat, Stn 1292; 20°22.4′ S, 164°06.8′ E; depth 0 m; Oct. 1993; Expédition Montrouzier leg.; marée, fonds meubles; MNHN • 1 specimen; Stn 952; 20°31′ S, 164°07′ E; depth 16–17 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen; Stn 946; 20°35′ S, 164°08′ E; depth 16–17 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 948; 20°32′ S, 164°09′ E; depth 16 m; 28 Apr. 1988; B. RicherORSTOM leg.; MNHN • 2 specimens; Stn 945; 20°35′ S, 164°10′ E; depth 15–16 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Passe du Baron, Stn KR644; 20°33.8′ S, 164°10.3′ E; depth unknown; 29 Sep. 2018; KOUMAC 2.1 leg.; fonds blancs; MNHN • 7 specimens, living; Grand Récif de Koumac, Stn KR218; 20°36.1′ S, 164°10.5′ E; depth 11 m; 16 Sep. 2018; KOUMAC 2.1 leg.; patate sur fonds blancs; DNA vouchers: MNHN-IM-2013-84747, -84748, -84749 • 23 specimens, living; Chenal de l’Infernet, Stn 1305; 20°36.2′ S, 164°11.0′ E; depth 12–15 m; Oct. 1993; Expédition Montrouzier leg.; sable gris; largest specimen 21.6 ×15.0 mm; MNHN • 5 specimens, living; Stn 943; 20°37′ S, 164°11′ E; depth 15 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 3 specimens; Stn 944; 20°35′ S, 164°12′ E; depth 14–15 m; 28 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Îlot Magone, Stn 1283; 20°33.5′ S, 164°12.2′ E; depth 0 m; Oct. 1993; Expédition Montrouzier leg.; marée, platier sableux; MNHN • 5 specimens, living; between Grand Récif de Koumac and l’Infernet, Stn KR607; 20°38.3′ S, 164°12.4′ E; depth 7–15 m; 5 Sep. 2018; KOUMAC 2.1 leg.; fonds blancs; DNA vouchers: MNHN-IM-2013-81081, -81082 • 30+ specimens, living; Chenal de l’Infernet, Stn 1306; 20°39.1′ S, 164°12.4′ E; depth 11–13 m; Oct. 1993; Expédition Montrouzier leg.; fonds blancs; MNHN • 1 specimen, living; Récif l’Infernet, Stn 1302; 20°35.8′ S, 164°12.7′ E; depth 9–10 m; Oct. 1993; Expédition Montrouzier leg.; pente interne; MNHN • 5 specimens, living; Stn KD542; 20°38.6′ S, 164°12.7′ E; depth 11 m; 7 Nov. 2019; KOUMAC 2.3 leg.; sable gris; MNHN • 1 specimen, dead; NW of Récif de l’Infernet, Stn KR619; 20°35.5′ S, 164°12.9′ E; depth 10 m; 19 Sep. 2018; KOUMAC 2.1 leg.; fond sablo-vaseux, tâches d’algues; MNHN • 1 specimen, living; Stn 941; 20°39′ S, 164°13′ E; depth 15–16 m; 27 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; between Grand Récif de Koumac and l’Infernet, Stn KR616; 20°38.5′ S, 164°13.1′ E; depth 15 m; 15 Sep. 2018; KOUMAC 2.1 leg.; fonds blancs; DNA vouchers: MNHN-IM-2013-84628, -84629 • 9 specimens, living; Chenal de l’Infernet, Stn 1304; 20°38.6′ S, 164°13.2′ E; depth 12–15 m; Oct. 1993; Expédition Montrouzier leg.; sable gris, dalle; MNHN • 2 specimens, living; Stn KD541; 20°39′ S, 164°13.3′ E; depth 11 m; 7 Nov. 2019; KOUMAC 2.3 leg.; sable gris; MNHN • 2 specimens, dead; around l’Îlot Kendec, Stn 1309; 20°40.5′ S, 164°13.4′ E; depth 18 m; Oct. 1993; Expédition Montrouzier leg.; sable gris; MNHN • 1 specimen, dead; close to Passe de Koumac, Stn KR627; 20°38.6′ S, 164°13.5′ E; depth 12 m; 24 Sep. 2018; KOUMAC 2.1 leg.; MNHN • 13 specimens, living; Stn KD516; 20°39.2′ S, 164°13.5′ E; depth 10 m; 1 Nov. 2019; KOUMAC 2.3 leg.; sable gris; DNA vouchers: MNHN-IM-2019-3429 (image LC158) and IM-2019-3430 • 4 specimens, living; Stn KS522; 20°39.3′ S, 164°13.6′ E; depth 15 m; 23 Nov. 2019; KOUMAC 2.3 leg.; sable blanc à Halophila; MNHN • 2 specimens, living; Récif de l’Infernet, Stn 1287; 20°37.0′ S, 164°14.0′ E; depth 0 m; Oct. 1993; Expédition Montrouzier leg.; marée, fonds divers; MNHN • 2 specimens, dead; Stn KD568; 20°40.1′ S, 164°14.3′ E; depth 2 m; 16 Nov. 2019; KOUMAC 2.3 leg.; sable blanc et quelques débris coralliens; MNHN • 1 specimen, living; Stn KD561; 20°45.4′ S, 164°14.4′ E; depth 1 m; 14 Nov. 2019; KOUMAC 2.3 leg.; sable grossier; MNHN • 6 specimens, living; Récif de l’Infernet, Stn 1301; 20°37.1′ S, 164°14.7′ E; depth 1–5 m; Oct. 1993; Expédition Montrouzier leg.; fonds divers; MNHN • 1 specimen, dead; Récif de l’Infernet, Stn KR632; 20°37.5′ S, 164°14.7′ E; depth 8 m; 25 Sep. 2018; KOUMAC 2.1 leg.; bord du platier; MNHN • 1 specimen, dead; Passe Deverd, Stn 1319; 20°44.7′ S, 164°15.5′ E; depth 15–20 m; Oct. 1993; Expédition Montrouzier leg.; dalle; MNHN • 5 specimens, living; Plateau Karembé, Stn 1286; 20°38′ S, 164°16′ E; depth 0 m; Oct. 1993; Expédition Montrouzier leg.; marée, fonds meubles avec blocs; MNHN • 1 specimen, living; Stn 940; 20°38′ S, 164°16′ E; depth 10 m; 27 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 4 specimens, living; Stn 936; 20°41′ S, 164°16′ E; depth 14–15 m; 27 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn KD572; 20°45.8′ S, 164°16.1′ E; depth 22–23 m; 18 Nov. 2019; KOUMAC 2.3 leg.; sable grossier, coquilles; MNHN • 4 specimens, living; Stn KD577; 20°45.8′ S, 164°16.2′ E; depth 21 m; 19 Nov. 2019; KOUMAC 2.3 leg.; fond dur, quelques algues brunes; MNHN • 2 specimens, living; Pointe Pandop, Stn KR625; 20°35.1′ S, 164°16.3′ E; depth 8 m; 23 Sep. 2018; KOUMAC 2.1 leg.; vase et petits rochers, débris coquilliers; MNHN • 2 specimens, living; Stn KD578; 20°43.8′ S, 164°16.4′ E; depth 11–12 m; 19 Nov. 2019; KOUMAC 2.3 leg.; sable fin gris à Halophila; MNHN • 1 specimen, dead; Stn KR1067; 20°38.4′ S, 164°16.5′ E; depth 18 m; 22 Nov. 2019; KOUMAC 2.3 leg.; plateforme sableuse et tombant de massif corallien intermédiaire; MNHN • 7 specimens, living; Stn KD574; 20°43.5′ S, 164°16.9′ E; depth 12 m; 19 Nov. 2019; KOUMAC 2.3 leg.; sable gris à Halophila; MNHN • 1 specimen; Stn 932; 20°46′ S, 164°17′ E; depth 23 m; 27 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn KD546; 20°41′ S, 164°17.1′ E; depth 6 m; 8 Nov. 2019; KOUMAC 2.3 leg.; sable grossier et algues; DNA voucher; MNHN-IM-2019-8224 • 3 specimens, living; Stn KD553; 20°47.9′ S, 164°17.2′ E; depth 5–10 m; 13 Nov. 2019; KOUMAC 2.3 leg.; sable blanc; DNA voucher; MNHN-IM-2019-8775 • 1 specimen, dead; Pointe N Plateau Karembé, Stn KM321; 20°37.6′ S, 164°17.3′ E; depth 0 m; 26 Sep. 2018; KOUMAC 2.1 leg.; platier intérieur, coraux et herbiers; MNHN • 2 specimens, living; Stn KD583; 20°43.5′ S, 164°17.3′ E; depth 12 m; 21 Nov. 2019; KOUMAC 2.3 leg.; sable fin; MNHN • 1 specimen, dead; Stn KR636; 20°39.6′ S, 164°17.5′ E; depth 2–5 m; 27 Sep. 2018; KOUMAC 2.1 leg.; fonds sableux; MNHN • 1 specimen, living; east of Kendec channel, Stn KR216; 20°43.3′ S, 164°17.6′ E; depth unknown; 15 Sep. 2018; KOUMAC 2.1 leg.; DNA voucher; MNHN-IM-2013-84485 • 1 specimen, living; Stn KD547; 20°42.2′ S, 164°18.2′ E; depth 2–6 m; 8 Nov. 2019; KOUMAC 2.3 leg.; sable grossier et herbier; DNA voucher, photographed alive (image LC398); MNHN-IM-2019-8234 • 1 specimen, living; between Grand Récif Mathieu and Îlot Deverd, Stn KR635; 20°47.9′ S, 164°18.2′ E; depth 15 m; 26 Sep. 2018; KOUMAC 2.1 leg.; fonds blancs; DNA voucher; MNHN-IM-2013-85258 • 7 specimens, living; Stn KD552; 20°49.4′ S, 164°18.5′ E; depth 10–11 m; 13 Nov. 2019; KOUMAC 2.3 leg.; sable blanc; DNA voucher; MNHN-IM-2019-8777 • 1 specimen, dead; caye de sable devant Kaala-Gomen, Stn 1288; 20°40.0′ S, 164°19.0′ E; depth 11–13 m; Oct. 1993; Expédition Montrouzier leg.; marée, fonds meubles; MNHN • 1 specimen, dead; Stn KR1068; 20°42.1′ S, 164°19.3′ E; depth 2 m; 23 Nov. 2019; KOUMAC 2.3 leg.; patch corallien et débris d’arrière récif intermédiaire; MNHN • 4 specimens, living; Pointe Devers, Stn KR1025; 20°46.2′ S, 164°22.6′ E; depth 4 m; 6 Nov. 2019; KOUMAC 2.3 leg.; fond vaseux à caulerpe, tombant de platier de récif frangeant; MNHN • 4 specimens, living; Stn 916; 20°56′ S, 164°28′ E; depth 13 m; 26 Apr. 1988; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Stn 913; 20°58′ S, 164°32′ E; depth 10–13 m; 26 Apr. 1988; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Touho • 1 specimen, living; parages de la Thiem, Stn 1268; 20°45.2′ S, 165°08.0′ E; depth 9–11 m; Sep. 1993; Expédition Montrouzier leg.; sable fin; MNHN • 1 specimen, dead; Grand Récif Mengalia, Stn 855; 20°38′ S, 165°09′ E; depth 22 m; 12 Jan. 1987; B. RicherORSTOM leg.; MNHN • 2 specimens, dead; vicinity of Baie de Touho, Stn 1251; 20°46.0′ S, 165°13.0′ E; depth 6–15 m; Sep. 1993; Expédition Montrouzier leg.; vase, sable, herbiers; MNHN • 6 specimens, living; Baie de Touho, Stn 1237; 20°46.9′S, 165°13.8′ E; depth 0–1 m; Sep. 1993; Expédition Montrouzier leg.; sable fin et herbiers abrités; MNHN • 5 specimens, dead; platform off the wharf of Touho, Stn 1242; 20°46.2′ S, 165°14.5′ E; depth 0 m; Sep. 1993; Expédition Montrouzier leg.; marée, blocs, sable, herbiers; MNHN • 1 specimen, living; Lagon du Grand Récif Mengalia, Stn 1264; 20°44.5′ S, 165°15.9′ E; depth 8 m; Sep. 1993; Expédition Montrouzier leg.; vase sableuse, dôme détritique; MNHN • 1 specimen, living; Grand Récif Mengalia, Stn 870; 20°38′ S, 165°16.0′ E; depth 37 m; 13 Jan. 1987; B. RicherORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Mengalia, Stn 1245; 20°45.2′ S, 165°16.3′ E; depth 0 m; Sep. 1993; Expédition Montrouzier leg.; marée, platier, sable, herbiers; MNHN. – Grande Terre, Bourail • 2 specimens, living; chenal du lagon de Poé, Stn 1326; 21°37.2′ S, 165°22.7′ E; depth 1–3 m; 1 Sep. 1993; Expédition Montrouzier leg.; MNHN. – Grande Terre, Poindimié • 1 specimen, dead; Stn 816; 20°53′ S, 165°25′ E; depth 31 m; 10 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 788; 21°02′ S, 165°35′ E; depth 33 m; 9 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 772; 21°08′ S, 165°41′ E; depth 30 m; 8 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn 763; 21°11′ S, 165°44′ E; depth 42 m; 8 Jan. 1987; B. RicherORSTOM leg.; MNHN. – Grande Terre, Canala • 1 specimen, dead; Stn 754; 21°13′ S, 165°49′ E; depth 36 m; 7 Jan. 1987; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 702; 21°27′ S, 166°08′ E; depth 37 m; 10 Aug. 1986; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 697; 21°28′ S, 166°10′ E; depth 35–36 m; 10 Aug. 1986; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Thio • 1 specimen, dead; Stn 682; 21°34′ S, 166°19′ E; depth 36–37 m; 9 Aug. 1986; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 676; 21°35′ S, 166°23′ E; depth 41 m; 9 Aug. 1986; B. RicherORSTOM leg.; MNHN. – Grande Terre, Baie de St Vincent • 4 specimens, living; Stn 214; 21°55′ S, 165°48′ E; depth 12 m; 20 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 9 specimens, living; Stn 186; 22°04′ S, 166°00′ E; depth 11 m; 19 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn 187; 22°03′ S, 166°02′ E; depth 13 m; 19 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 7 specimens, living; Stn 188; 22°03′ S, 166°02′ E; depth 15 m; 21 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, dead; Stn 170; 22°09′ S, 166°07′ E; depth 22 m; 18 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 173; 22°08′ S, 166°07′ E; depth 20–50 m; 18 Sep. 1984; B. RicherORSTOM leg.; MNHN • 6 specimens, living; Stn 163; 22°12′ S, 166°08′ E; depth 15 m; 18 Sep. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Stn 162; 22°13′ S, 166°09′ E; depth 10 m; 18 Sep. 1984; B. Richer-ORSTOM leg.; MNHN. – Grande Terre, Nouméa • 16 specimens, living; Stn DE56; 22°08.4′ S, 166°07.7′ E; depth 19–20 m; no date; B. Richer-ORSTOM leg.; MNHN • 7 specimens, living; Stn DE54; 22°11.9′ S, 166°08.3′ E; depth 13 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 3 specimens, living; Stn DE53; 22°13.4′ S, 166°10.1′ E; depth 10 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 2 specimens, living; Stn 51; 22°15′ S, 166°11′ E; depth 10 m; 25 May 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn DE52; 22°15.1′ S, 166°11.3′ E; depth 9–10 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 17 specimens, living; Stn 50; 22°17′ S, 166°12′ E; depth 12 m; 25 May 1984; B. Richer-ORSTOM leg.; MNHN • 4 specimens, living; Stn DE51; 22°16.8′ S, 166°12.5′ E; depth 10–11 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, dead; Stn 49; 22°19′ S, 166°14′ E; depth 10 m; 25 May 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn DE60; 22°13.6′ S, 166°14.1′ E; depth 21 m; 30 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 3 specimens, living; Stn DE50; 22°18.0′ S, 166°14.1′ E; depth 15–16 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, living; Stn DE49; 22°19.8′ S, 166°14.5′ E; depth 19–20 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 2 specimens, dead; Stn 40; 22°21′ S, 166°15′ E; depth 21 m; 24 May 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 277; 22°17′ S, 166°16′ E; depth 30 m; 8 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Grand Récif Aboré, Stn 1346; 22°21.9′ S, 166°16.1′ E; depth 5–6 m; 5 Oct. 1992; P. Bouchet leg.; fonds blanc; MNHN • 2 specimens, living; Stn DE48; 22°20.8′ S, 166°16.2′ E; depth 20– 24 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen; Stn DE62; 22°16.8′ S, 166°16.6′ E; depth 32–34 m; 30 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, dead; Stn 8; 22°23′ S, 166°18′ E; depth 15 m; 21 May 1984; B. Richer-ORSTOM leg.; MNHN • 8 specimens, living; Stn DE46; 22°23.4′ S, 166°18.8′ E; depth 10–11 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 6 specimens, living; Stn 257; 22°22′ S, 166°20′ E; depth 9 m; 7 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 6 specimens, living; Stn 7; 22°24′ S, 166°20′ E; depth 14 m; 21 May 1984; B. RicherORSTOM leg.; MNHN • 2 specimens, dead; Stn 255; 22°25′ S, 166°20′ E; depth 11 m; 25 May 1984; B. Richer-ORSTOM leg.; MNHN • 4 specimens, dead; Grand Récif Aboré, Stn 1347; 22°23.6′ S, 166°20.1′ E; depth 10 m; 8 Oct. 1992; P. Bouchet leg.; vase sableuse sur dalle; MNHN • 7 specimens, living; Stn DE45; 22°24.7′ S, 166°20.7′ E; depth 10 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 9 specimens, living; Île aux Goélands, Stn 1368; 22°24.3′ S, 166°20.7′ E; depth 10 m; 16 Apr. 1993; P. Bouchet leg.; fonds blancs; MNHN • 5 specimens, living; Stn 4; 22°23′ S, 166°21′ E; depth 9 m; 21 May 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Crouy; 22°21.5′ S, 166°21.7′ E; depth 1–6 m; 1990–2003; Berthault leg.; MNHN • 2 specimens, living; Île aux Goélands, Stn 1503; 22°22.4′ S, 166°22.5′ E; depth 5–7 m; 21 Oct. 2000; Cosel and Trondlé leg.; MNHN • 2 specimens, living; Stn 253; 22°22′ S, 166°23′ E; depth 16 m; 7 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 21; 22°23′ S, 166°23′ E; depth 10 m; 23 May 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 2; 22°19′ S, 166°24′ E; depth 14 m; 21 May 1984; B. Richer-ORSTOM leg.; MNHN • 20 specimens, living; Stn 281; 22°24′ S, 166°24′ E; depth 10 m; 9 Nov. 1984; B. RicherORSTOM leg.; MNHN • 1 specimen, living; Stn 283; 22°27′ S, 166°24′ E; depth 13 m; 9 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Îlot Maître, Stn 1361; 22°20.2′ S, 166°24.3′ E; depth 6 m; 24 Mar. 1993; P. Bouchet leg.; sable grossier dans herbier mixte; MNHN • 2 specimens, living; Stn DE43; 22°26.5′ S, 166°24.3′ E; depth 11–12 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 3 specimens, living; Ile Ouen-Baie du Prony, Stn 64; 22°28′ S, 166°25′ E; depth 15 m; 20 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Stn 284; 22°26′ S, 166°25′ E; depth 6 m; 9 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 20 specimens, living; Stn DE42; 22°27.5′ S, 166°25.3′ E; depth 15 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 7 specimens, living; Baie des Citrons; 22°17.5′ S, 166°26.2′ E; depth 1–5 m; 1987–2007; Berthault leg.; MNHN • 1 specimen, dead; Ile Ouen-Baie du Prony, Stn 63; 22°26′ S, 166°26′ E; depth 20 m; 20 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 7 specimens, living; Ile Ouen-Baie du Prony, Stn 66; 22°28′ S, 166°27′ E; depth 15 m; 20 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 9 specimens, living; Passe de Boulari; 22°31.4′ S, 166°27.5′ E; depth 15 m; 21Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, living; Stn DE41; 22°28.2′ S, 166°27.7′ E; depth 19–21 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, living; Stn DE39; 22°31.9′ S, 166°28.1′ E; depth 33–34 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, dead; Baie de Sainte Marie–Îlot Uéré; 22°18.5′ S, 166°28.3′ E; depth 0–3 m; 1995-2003; Claude Berthault leg.; MNHN • 8 specimens, living; Stn DE38; 22°33.6′ S, 166°28.6′ E; depth 22–24 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 2 specimens, dead; Ile Ouen-Baie du Prony, Stn 82; 22°33′ S, 166°29′ E; depth 10 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn DE37; 22°34.5′ S, 166°30.0′ E; depth 20–21 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 4 specimens, living; Ile Ouen-Baie du Prony, Stn 83; 22°32′ S, 166°30′ E; depth 22 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn DE70; 22°25.6′ S, 166°31.0′ E; depth 20–21 m; 30 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, living; Ile Ouen-Baie du Prony, Stn 84; 22°30′ S, 166°31′ E; depth 17 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn 29077; 22°16′ S, 166°32′ E; depth 11 m; 9 Nov. 1984; B. RicherORSTOM leg.; MNHN • 5 specimens, living; Stn DE36; 22°35.5′ S, 166°32.0′ E; depth 17–19 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 8 specimens, living; Ile Ouen-Baie du Prony, Stn 98; 22°36′ S, 166°32′ E; depth 15 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 4 specimens, dead; Ile Ouen-Baie du Prony, Stn 95; 22°31′ S, 166°33′ E; depth 14 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Stn DE35; 22°36.5′ S, 166°33.8′ E; depth 16 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 2 specimens, living; Ile Ouen-Baie du Prony, Stn 100; 22°33′ S, 166°35′ E; depth 15 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Ile Ouen-Baie du Prony, Stn 99; 22°33′ S, 166°35′ E; depth 14 m; 21 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn DE34; 22°37.7′ S, 166°35.8′ E; depth 19–21 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 5 specimens, living; Stn DE33; 22°38.4′ S, 166°38.0′ E; depth 31–33 m; 29 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 13 specimens, living; Ile Ouen-Baie du Prony, Stn 226; 22°38′ S, 166°39′ E; depth 28 m; 22 Oct. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Stn DE30; 22°35.8′ S, 166°39.6′ E; depth 12–13 m; 28 Apr. 1987; B. Richer de Forges-IRD leg.; MNHN • 1 specimen, dead; Ile Ouen-Baie du Prony, Stn 105; 22°25′ S, 166°41′ E; depth 33 m; 22 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 15 specimens, living; Grand Récif Sud, Stn 293; 22°42′ S, 166°41′ E; depth 20 m; 26 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Grand Récif Sud, Stn 294; 22°44′ S, 166°42′ E; depth 21 m; 26 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Grand Récif Sud, Stn 296; 22°41′ S, 166°44′ E; depth 26 m; 26 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Grand Récif Sud, Stn 291; 22°38′ S, 166°44′ E; depth 31 m; 26 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Grand Récif Sud, Stn 306; 22°43′ S, 166°45′ E; depth 38 m; 27 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 4 specimens, dead; Ile Ouen-Baie du Prony, Stn 233; 22°35′ S, 166°46′ E; depth 30 m; 22 Oct. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Grand Récif Sud, Stn 305; 22°42′ S, 166°46′ E; depth 26 m; 27 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, dead; Grand Récif Sud, Stn 341; 22°49′ S, 166°46′ E; depth 19 m; 28 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 304; 22°40′ S, 166°48′ E; depth 27 m; 27 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 3 specimens, dead; Grand Récif Sud, Stn 339; 22°46′ S, 166°48′ E; depth 26 m; 28 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, living; Grand Récif Sud, Stn 312; 22°42′ S, 166°49′ E; depth 26 m; 27 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Grand Récif Sud, Stn 345; 22°46′ S, 166°50′ E; depth 39 m; 29 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Ile Ouen-Baie du Prony, Stn 149; 22°29′ S, 166°51′ E; depth 48 m; 24 Aug. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 336; 22°42′ S, 166°51′ E; depth 26 m; 28 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 555; 22°50′ S, 166°51′ E; depth 32 m; 16 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Grand Récif Sud, Stn 547; 22°55′ S, 166°53′ E; depth 29 m; 15 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 559; 22°44′ S, 166°55′ E; depth 52 m; 28 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 564; 22°47′ S, 166°56′ E; depth 35 m; 16 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Grand Récif Sud, Stn 331; 22°33′ S, 166°59′ E; depth 79 m; 28 Nov. 1984; B. Richer-ORSTOM leg.; MNHN • 2 specimens, dead; Grand Récif Sud, Stn 410; 22°42′ S, 167°22′ E; depth 35 m; 24 Jan. 1985; B. RicherORSTOM leg.; MNHN. – Grande Terre, Yaté • 1 specimen, dead; Stn 641; 21°53′ S, 166°43′ E; depth 50–52 m; 7 Aug. 1986; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 633; 21°56′ S, 166°48′ E; depth 50 m; 6 Aug. 1986; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 632; 21°57′ S, 166°50′ E; depth 44–45 m; 6 Aug. 1986; B. Richer-ORSTOM leg.; MNHN • 1 specimen, dead; Stn 624; 21°60′ S, 166°52′ E; depth 46– 44 m; 6 Aug. 1986; B. Richer-ORSTOM leg.; MNHN. – Île des Pins • 1 specimen, living; Stn 592; 22°34′ S, 167°22′ E; depth 22 m; 18 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 8 specimens, living; Stn 590; 22°30′ S, 167°24′ E; depth 20 m; 18 Jul. 1985; B. RicherORSTOM leg.; MNHN • 4 specimens, dead; Stn 589; 22°32′ S, 167°24′ E; depth 31 m; 18 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 11 specimens, living; Stn 591; 22°36′ S, 167°24′ E; depth 14 m; 18 Jul. 1985; B. Richer-ORSTOM leg.; MNHN • 1 specimen, living; Stn 581; 22°42′ S, 167°26′ E; depth 23 m; 18 Jul. 1985; B. Richer-ORSTOM leg.; MNHN. – Loyalty Islands, Ouvéa • 1 specimen, living; Lagon d’Ouvéa, Stn 1231; 20°31′ S, 166°23′ E; depth 23 m; 9 Sep. 1992; NO Alis -PLOUVEAL leg.; MNHN • 1 specimen, living; Lagon d’Ouvéa, Stn 1229; 20°37′ S, 166°23′ E; depth 16 m; 15 Sep. 1992; NO Alis - PLOUVEAL leg.; MNHN • 1 specimen, dead; Lagon d’Ouvéa, Stn 1232; 20°32′ S, 166°24′ E; depth 31 m; 9 Sep. 1992; NO Alis -PLOUVEAL leg.; MNHN • 1 specimen, living; Lagon d’Ouvéa, Stn 1233; 20°29.1′ S, 166°29.0′ E; depth 15 m; 12 Sep. 1992; NO Alis -PLOUVEAL leg.; MNHN. – Loyalty Islands, Lifou • 6 specimens, living; Baie du Santal, north of Cap Aimé Martin [= Acadro], Stn 1450; 20°45.8′ S, 167°01.6′ E; depth 27–31 m; 17 Nov. 2000; Atelier LIFOU 2000 leg.; brossages; MNHN • 1 specimen, dead; Baie du Santal, in front of Ngoni beach, Stn 1458; 20°46.7′ S, 167°03.1′ E; depth 17–24 m; 4 Nov. 2000; Atelier LIFOU 2000; dredged; MNHN • 2 specimens, living; Baie du Santal, Baie de Gaatcha, Stn 1463; 20°55′ S, 167°03.3′ E; depth 20–30 m; 10 Nov. 2000; Atelier LIFOU 2000; dragages sable et débris coralliens; MNHN • 1 specimen, dead; Baie du Santal, Baie de Gaatcha, Stn 1419; 20°55.6′ S, 167°04.5′ E; depth 5 m; 10 Nov. 2000; Atelier LIFOU 2000; limon sur dalle, algues photophiles; MNHN • 12 specimens, living; Baie du Santal, in front of landing beaches at Drueulu, Stn 1413; 20°55.3′ S, 167°05.0′ E; depth 3–10 m; 26 Nov. 2000; Atelier LIFOU 2000 leg.; fonds meubles; MNHN .

Description (Fig. 8)

SHELL. A moderate to large, globose-lenticular species (diameter up to 22 mm, but usually <18 mm) with a glossy, typically Ethalia -like shell; last adult whorl deep, periphery below mid-whorl, suture shallowly sunken (Fig. 9A); whorl profile variable, some specimens with indistinct rounded shoulder (Fig. 8N). Although glossy, shell not without sculpture; early teleoconch whorls with fine spiral lirae (Fig. 9B) that become broader and more flat-topped with growth; sculpture appearing to comprise incised striae rather than raised lirae on mid-spire whorls; evanescing to a variable extent on last whorl which is sculptured primarily by fine close-set growth-lines. Much of base almost completely smooth, but peri-umbilical area somewhat thickened and bearing microscopic spiral threads and curved axial threads; umbilicus of adult specimens almost completely plugged by callus extending from paries, a small umbilical chink usually remaining; callus lustreless and indistinctly wrinkled; umbilicus patent in juveniles, becoming progressively more obstructed by callus with growth (Fig. 8R–T). Columella lip thick, with a nacreous mid-region between parietal callus and thickened termination of umbilical rim, the latter with indistinct oblique ridges.

COLOUR. Pattern variable, but ground colour usually pale fawn-grey to pale fawn-brown, mottled with darker lines and blotches in shades of olive-green, grey-green, grey-brown and reddish-brown; subsutural region often with a band of radiating brown or red-brown lines (Fig. 8F, L), between this and periphery are several capillary lines of alternating white and darker chevron-like marks; periphery and outer region of base uniformly white or with bold red-brown or maroon-brown trigonal blotches that extend on to outer base (Fig. 8M); remainder of base uniformly dirty-white to yellowish-white, but thickened peri-umbilical region frequently heavily marked with grey-brown or maroon-brown; umbilical callus and columella white, but columella base and area around umbilical chink sometimes yellow or yellowish-orange (Fig. 8H). Coloration of specimens from the Chesterfield-Bellona Plateau often of a more pinkish hue (Fig. 8Q).

PROTOCONCH (Fig. 9C). Typically umboniine, diameter ± 200 µm; apical beak present and confluent with terminal lip; apical bulb mostly worn but with traces of an irregular network of fine threads; terminal lip weakly convex.

OPERCULUM (Fig. 9D). Corneous, moderately thick, dark yellow-brown; multispiral, but not tightly so and with relatively long growing margin; peripheral fringe narrow, whorl overlap limited; surface lacking spiral microsculpture.

RADULA (Fig. 10). Formula ∞+(1)+5 +1+5 +(1) +∞, with ±50 transverse rows of teeth; teeth in central field with distinct base-plates, but shafts and cusps lacking; rachidian broader than long; laterals 1–4 subtriangular, pinched in anteriorly (shaft vestige); laterals 2–4, with outer margin slightly raised and somewhat thickened; fifth lateral subquadrate, elongate. Innermost marginal transitional, with stout base-plate and reduced shaft and cusp; other marginal teeth well developed with narrow shaft and strongly recurved cusp; cusps of inner marginal teeth with large bluntly lanceolate central denticle bearing 1–2 small pointed denticles at its outer base and an even smaller, more slender one at inner base (usually not visible due to tooth overlap); marginals 3–10 with largest cusps; cusps progressively smaller and with more numerous, finer denticles thereafter, outermost ones with finely pectinate margins.

EXTERNAL ANATOMY (from photographs and rehydrated specimens) (Fig. 11). Head with distinct forehead between cephalic tentacles; snout moderately long, cylindrical, a single transverse row of digit-like papillae halfway down anterior face, additional, similar papillae present in distal quarter; cephalic lappets small and smooth-edged; cephalic tentacles long and slender, micropapillate, left and right of similar size; eyestalks long, their tips conspicuously expanded and containing large black eyes with eye aperture directed upwards; left neck-lobe a row of 10–15 close-set, non-papillate digit-like projections, larger anteriorly and alternating in size, progressively smaller posteriorly; right neck-lobe well developed, rolled to form an exhalant siphon; four micropapillate epipodial tentacles on each side, each with a well-developed stalked epipodial sense organ near its base; an epipodial sense organ also present beneath each neck-lobe; propodium slightly indented in mid-line with a small lateral propodial lobe on each side; foot flattened with broad sole, tapering posteriorly. Head-foot mostly pale translucent greyish-white; eyestalks, left neck-lobe digits, epipodial fringe and sense organs with opaque white pigmentation; forehead and anterior of snout often tinged yellowish-brown; columellar region above operculum darker yellowish-brown; cephalic and epipodial tentacles with faint transverse dark bands; sides of foot white, its sole often with grey-brown mottling. Ctenidium for the most part bipectinate, anterior portion unattached.

Habitat

Very common in lagoonal habitats; living specimens mostly at depths of 0–30 m, exceptionally to 61 m; largely associated with white and grey sandy substrata in the channels between reefs.

Distribution (Fig. 12)

To date known only from the New Caledonian marine ecoregion, with records from the Chesterfield-Bellona Plateau, d’Entrecasteaux Reefs, Belep, Grande Terre, Île des Pins and the Loyalty Islands.

Remarks

In 1996, I concluded that Rotella montrouzieri belonged to the Ethalia guamensis complex (sensu Pilsbry 1889 –1890 and Pilsbry 1905), noting that it required further study due to unresolved taxonomic issues associated with this complex (Herbert 1996). To a large extent these issues have been resolved in the intervening years. The Japanese Ethalia guamensis sanguinea Pilsbry, 1905 is now considered to be a separate species (Higo et al. 1999; Sasaki 2000) whereas Ethalia guamensis selenomphala Pilsbry, 1905 is not considered distinct from E. guamensis (Higo et al. 1999) .

It is now evident that E. montrouzieri, treated as another subspecies of E. guamensis by Pilsbry (1905), but considered a synonym of E. guamensis by Higo et al. (1999), is also a distinct species. In E. guamensis a callus pillar appears to rise out of the umbilicus and fuses with the parietal region, leaving a narrow and deep semi-circular umbilical cavity. Whereas in E. montrouzieri, the callus arises as a tongue-like deposit in the parietal region that enlarges with growth until it almost completely occludes the umbilicus, leaving only a small chink-like opening between it and the thickened peri-umbilical rim. In this respect, it closely resembles Ethalia catharinae Poppe, Tagaro & Dekker, 2006 from the Philippines, which is undoubtedly a closely related species. The description of E. catharinae matches the features of E. montrouzieri to a considerable degree, except that the spiral sculpture of the early whorls is said to disappear during the third whorl, and later whorls are smooth and glossy. In addition, its umbilical callus is of a uniform yellowish-green colour. In E. montrouzieri the spiral sculpture on the early whorls likewise consists of fine cords, but with growth these transform into incised spiral striae that persist throughout, albeit with considerable individual variation in the strength and density of the striation on the last adult whorl. Furthermore, the umbilical callus in E. montrouzieri is normally uniformly white (occasional specimens have the columella lip tinged with orange-yellow, Fig. 8E–H) and there is frequently a broad brownish peri-umbilical band. It is difficult to evaluate the significance of these differences, considering the geographical distance between the populations, and further insight must await molecular studies.

The holotype of Rotella montrouzieri from Île Art, Belep (Fig. 8A–D) has relatively dense spiral striation and appears less glossy than material from Grande Terre. Whilst the later may simply be related to the age of the specimen, recently collected material from Lifou (Fig. 8J) also shows more dense spiral striation on the last whorl, suggesting regional variation in this feature.