Leptoconchus incycloseris sp. nov.

(Figs. 3, 21–23)

Etymology. The specific epithet reflects that the species has been found exclusively in corals of Fungia (Cycloseris), viz. F. (C.) costulata and F. (C.) tenuis . For the purposes of nomenclature, it is herewith declared (under ICZN 1999 Article 26) as not to be treated as a Greek, Latin or latinized word; thus, the spelling presented here is to remain unchanged.

Type material. Holotype female (RMNH 102613), found in the mushroom coral Fungia (Cycloseris) costulata; Palau, NE of Ngeremdiu, Lighthouse Reef, forereef, 07°16′30″N 134°27′25″E.

Paratypes (Fc = found with Fungia costulata; Ft = with F. tenuis). Palau: type locality (RMNH 102614/e found with holotype, 102615*/1sh: m in same coral as holotype); SW of Ubelsechel, N of Toachel Ra Ngel, 07°17′50″N 134° 29′08″E (RMNH 102616* Ft/1sn: f+e).

Indonesia. NE Kalimantan: Berau Islands, SW Baliktaba Reef, N Panjang Island, 02°34′43″N 118°00′48″E (RMNH 102617 Fc/2sn: m&f) .

SW Sulawesi: Spermonde Archipelago: W Kudingareng Keke Island, 05°06′09″S 119°17′09″E (RMNH 87830 Fc/ 1sn: f+e, 87833 Fc/1sn: f, 90051/1sn: f); SW Kudingareng Keke Island, 05°06′21″S 119°17′03″E (RMNH 90105 * Fc/ 1sn: f+e); W Badi Island, 04°58′05″S 119°16′54″E (RMNH 90037 Fc/1sh: f); SW Bone Tambung, 05°02′12″S 119°16′ 19″E (RMNH 87860 * Fc/1sn: f 1sh: f) .

Bali: Tulamben Beach, 08°16′36″S 115°35′37″E (RMNH 102618 * Fc/2sn: m&f+e); do., SE end, drop-off, 08°16′40″S 115°35′45″E (RMNH 102619 Fc/1sn: f) .

Diagnosis. Among the Leptoconchus species with reduced and variable morphological characters and associated with fungiid corals, L. incycloseris sp. nov. is differentiated by a unique combination of nucleotides in the Cytochrome Oxidase I barcoding sequence (GB: EU215812–EU215816, EU215861, EU215866, EU215870–EU215872), as indicated by underlined letters in Fig. 48.

Shell. Holotype female (Figs. 21, 22) H 10.7 mm, W 10.7 mm; columellar callus covering more than half surface of last whorl; outer lip with obtuse angle at shell base. H and W of largest female shell 18.9 mm and 19.1 mm, respectively, versus 9.4 mm and 6.1 mm for largest male. Male shell (Fig. 23) found with holotype H 6.9 mm, W 5.5 mm. Apex of shell protrudes distinctly above apertural edge in both sexes (Figs. 21, 23).

Habitat. The snails and their egg capsules were found at 5–24 m depth, with the mushroom coral species Fungia (Cycloseris) costulata Ortmann, 1889, and F. (C.) tenuis Dana, 1846 . The siphon pores are located on the upper side of the corals. Massin (2002) reported a Leptoconchus specimen associated with another coral species of the subgenus Cycloseris, viz. F. (C.) vaughani Boschma, 1923, from Papua New Guinea. This specimen may belong to

Leptoconchus incycloseris as well.

Distribution. The range of Leptoconchus incycloseris extends from Indonesia to Palau.