Leptoconchus massini sp. nov.

(Figs. 3, 30–32)

Etymology. This species is named after Claude Massin, who has contributed substantially to our knowledge of these hidden snails.

Type material. Holotype female (RMNH 95888), found in the mushroom coral Fungia (Verrillofungia) concinna; Thailand, Phi Phi Islands, NE Koh Phi Phi Le, Pi Le Bay, near cave, 07°41′43″N 98°45′57″E.

Paratypes (Fc = found with Fungia concinna; Fr = with F. repanda; Fs = with F. scabra; Fh = with F. horrida). Thailand. Phi Phi Islands: type locality (RMNH 102652/e found with holotype, 102653 Fc/1sn: f+e 1sh: m in same coral as holotype, 95887 Fc/1sn: f+e 1sh: f, 95889 Fc/2sn: m&f+e, 95890 Fc/1sn: f, 95891 Fc/2sn: m&f); S Koh Phi Phi Le, Loh Samah, 07°40′28″N 98°46′10″E (RMNH 95979 Fr/2sn: f); S Koh Phi Phi Don, 07°43′07″N 98°46′16″E (RMNH 95874 Fc/2sn: m&f+e, 95873 Fc/2sn: m&f+e); E Koh Phi Phi Don, 07°44′59″N 98°47′09″E (RMNH 95935 Fc/1sn: f, 95936 Fc/2sn: m&f+e 1sh: f).

Egypt. Red Sea, 350 km S of Hurghada (RMNH 102654 * Fr/1sn: f+e) .

Palau. NE of Ngeremdiu, Lighthouse Reef, forereef, 07° 16′30″N 134°27′25″E (RMNH 102655 * Fc/1sn: m 1sh: f, 102657 Fr/2sn: m&f+e) ; S of Garreru, Uchelbeluu Reef, inside barrier reef, 07°16′04″N 134°32′26″E (RMNH 102657 Fr/2sn: m&f, 102658 Fr/2sn: m&f+e) .

Indonesia. NE Kalimantan, Berau Islands: E Derawan Island, 02°17′32″N 118°15′43″E (RMNH 102659 Fr/1sn: f 1sh: f) .

N Sulawesi: SW of Gorontalo, 00°21′31″N 124°03′14″ E (RMNH 102660 Fh/3sn: 2m&1f+e, 102661 Fr/3sn: 2 m &1f+e) .

Central Sulawesi, Tomini Bay, Togian Islands: Walea Lighthouse, 00°25′19″S 122°26′08″E (RMNH 102662 Fr/ 1sn: f 2sh: m&f, 102663 Fr/2sn: m&f+e); S Waleabahi Island, barrier reef, 00°26′16″S 122°15′57″E (RMNH 102664 Fr/2sn: m&f+e, 102665* Fc/2sn: m&f); S Talatakoh Island, barrier reef, 00°29′39″S 122°04′21″E (RMNH 102666 Fr/1sn: f 1sh: f, 102667 Fr/3sn: 2m &1f); S Togian Island, patch reef, 00°25′ 31″S 122°00′11″E (RMNH 102668 Fr/1sn: f 1sh: f); S Batudaka Island, patch reef, 00°35′25″S 121°41′38″E (RMNH 102669 * Fh/3sn: 1m &2f+e 2sh: f); W Batudaka Island, Copatana Cape, 00°35′50″S 121°37′13″E (RMNH 102670 Fr/3sn: 2m &1f+e) .

SW Sulawesi, Spermonde Archipelago: W Bona Baku Reef, 05°07′56″S 119°21′39″E (RMNH 90087 * Fs/2sn: m&f+e); W Bone Lola Reef, 05°03′07″S 119°21′09″E (RMNH 90022 * Fr/2sn: m&f+e); SW Kudingareng Keke Island, 05°06′21″S 119°17′03″E (RMNH 87868 Fr/1sh: f, 87871 Fr/2sn: m&f, 87872 Fc/2sn: m&f+e, 87873* Fc/2sn: m&f+e, 87874 Fc/1sn: f); NW Kapodasang Reef, 05°05′ 38″S 119°14′45″E (RMNH 90072 Fr/2sn: m&f+e); W Kapodasang Reef, 05°05′35″S 119°15′20″E (RMNH 90089 * Fr/2sn: m&f+e, 90090 Fr/1sn: m 1sh: f, 90096 Fr/ 2sn: m&f, 90097 Fr/1sn: f 2sh: f, 90098 Fc/1sn: f, 90099 Fr/2sn: m&f+e, 90100 Fc/2sn: m&f); NW Bone Tambung Island, 05°02′05″S 119°16′16″E (RMNH 90093 Fc/2sn: m&f); SW Bone Tambung, 05°02′12″S 119°16′19″E (RMNH 87862 Fc/1sn: m 1sh: f); W Badi Island, 04°58′ 05″S 119°16′54″E (RMNH 90039 Fc/3sn: 1m &2f+e) .

Bali: Padang Bai, Tanjung Sari, 08°31′11″S 115°30′37″E (RMNH 102671 Fr/1sn: f+e, 102672* Fr/2sn: f+e); Tulamben Beach, 08°16′36″S 115°35′37″E (RMNH 102673 Fr/2sn: 2f +e); Tulamben Beach, 08°16′43″S 115°35′49″E (RMNH 102674 Fr/1sn: f+e, 102675 Fr/2sn: m&f+e, 102677 Fr/2sn: m&f+e) .

Diagnosis. Among the Leptoconchus species with reduced and variable morphological characters and associated with fungiid corals, L. massini sp. nov. is differentiated by a unique combination of nucleotides in the Cytochrome Oxidase I barcoding sequence (GB: EU215809–EU215811, EU215827, EU215848–EU215851, EU215853, EU215867– EU215869, EU215891–EU215895), as indicated by underlined letters in Fig. 48.

Shell. Holotype female (Figs. 30, 31) H 13.5 mm, W 18.4 mm; columellar callus covering more than half of surface of last whorl; entire outer lip regularly curved. H and W of largest female 14.1 mm and 22.5 mm, respectively, versus H 11.8 mm and W 13.5 mm for largest male (found with holotype; Fig. 32). Apical part of female shell protrudes slightly above apertural edge (Fig. 30), apex of male shell protrudes distinctly (Fig. 32).

Habitat. The snails and their egg capsules were found at 5–16 m depth, in the mushroom coral species Fungia (Verrillofungia) concinna Verrill, 1864, F. (V.) repanda Dana, 1846, F. (V.) scabra Döderlein, 1846, and F. (Danafungia) horrida Dana, 1846 . The siphon pores are located on the upper side of the corals.

Distribution. The range of Leptoconchus massini extends from the Red Sea to Thailand, Palau and Indonesia.