Leucosyrinx bourgeoisae Kantor & Fedosov & Puillandre 2025, sp. nov.

Leucosyrinx bourgeoisae sp. nov. urn:lsid:zoobank.org:act: A0CCDF20-A2A0-4331-B845-A5A531C4B385 Figs 15H, 19G–L Etymology The species is named after Mauricette Bourgeois, a volunteer of many years in the malacology division of MNHN. Material examined Holotype (sequenced) BISMARCK SEA • N Long I.; 5°9′ S, 147°2′ E; depth 805–865 m; PAPUA NIUGINI, stn DW3985; MNHN-IM-2013-19785. Other material (all sequenced) NEW CALEDONIA • 1 lv; SE Fairway; 21°32′ S, 162°32′ E; depth 775–792 m; EBISCO; stn CP2649; MNHN-IM-2009-13417. PAPUA NEW GUINEA • 1 lv; New Britain, north of Rabaul; 4°3′ S, 151°50′ E; depth 788–805 m; BIOPAPUA, stn CP3674; MNHN-IM-2009-17002. SOLOMON ISLANDS • 1 lv; 7°31′ S, 156°18′ E; depth 782–884 m; SALOMON 2, stn CP2249; MNHN-IM-2009-13590. Description MEASUREMENTS (holotype). SL 32.1 mm, AL (with canal) 15.0 mm, AL (without canal) 9.9 mm, SW 11.3 mm. SHELL (holotype). Shell medium-sized, thin, fragile, broad fusiform, with medium high spire, very light-yellowish in color, nearly white. Paucispiral, small, bulbous protoconch of about 1.75 rounded light brown and microshagreened whorls, protoconch–teleoconch transition marked by distinct growth line and appearance of shoulder keel. 9.75 distinctly roundly angled at shoulder teleoconch whorls, with weekly concave subsutural ramp, nearly flat on last and penultimate whorls. Distinct, shallow, impressed suture. 15 medium strong, oblique, short axial folds, forming rounded closely spaced knobs on shoulder of last whorl and 16 on penultimate whorl. Folds fade on subsutural ramp, reach the lower suture on upper 4–5 whorls. On last whorl folds disappear shortly below shoulder. On last and penultimate whorls, intervals between folds slightly exceed folds’ width. Distinct spiral sculpture below shoulder of slightly varying in width, low, slightly wavy cords over entire shell below shoulder, including canal. Intervals between cords 1–2 cords’ width. On subsuturtal ramp sculpture indistinct, of very weak spiral striation. Numerous thin but distinct growth lines. Shell base rounded, strongly convex, rapidly constricting and passing into long rather narrow, and straight canal. Medium broad, elongate-oval aperture poorly differentiated from canal, inner lip weakly convex. Columellar and parietal sides with narrow, distinct white callus. Deep, subsutural, broadly arcuate anal sinus extends across subsutural ramp, confluent with large forward extension of outer lip (judging from growth lines, since outer lip partially broken). RADULA (Fig. 15H; studied in holotype). Medium long, comprising about 35 rows of teeth, 11–12 nascent. Marginal teeth duplex, ~350 µm in length (3.5% AL without canal). Major limb narrow lanceolate in dorsal view, curved. Accessory limb about half of tooth width, ~0.75 of total tooth length, inserted into distinct socket on dorsal side of major limb. DNA diagnosis (based on 3 cox 1 sequences) ‘C’ in site 50, ‘C’ in site 401, ‘G’ in site 403, ‘C’ in site 586. Remarks The species is moderately variable in shell shape and sculpture. Shell is from narrow to broad fusiform with a rapidly to gradually narrowing towards the canal base. In the single specimen from New Caledonia (Fig. 19L) the axial folds extend well to the shell base and reach the lower suture on the teleoconch whorls. The species resembles Leucosyrinx sp. 18 and L. margaritae. From the former it differs in a generally broader shell and less pronounced shoulder knobs. From the latter, although being its sister species in the phyloegentic tree, it differs in having a somewhat shorter siphonal canal, although a clear morphological distinction can not be drawn. The studied specimen from New Caledonia is extremely similar to Leucosyrinx sp. 2 (Fig. 19N). Distribution From New Caledonia to Papua New Guinea and Bismarck Sea, 775– 805 m.