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

Leucosyrinx quinetae sp. nov. urn:lsid:zoobank.org:act: 155AB07E-50EC-4DD0-A646-6CF0A642B2D1 Figs 20G, 24A–G Leucosyrinx luzonica – Kantor et al. 2018: 75, 77, figs 20d, 21b–f (non Powell, 1969). Etymology The species is named after Béatrice Quinet, a volunteer of many years in the molluscan team of MNHN. Material examined Holotype (sequenced) SOUTH CHINA SEA • S of Taiping I.; 10°26′ N, 114°14′ E; depth 1707–1799 m; NanHai 2014, stn CP4108; MNHN-IM-2013-44303. Other material (all sequenced) SOUTH CHINA SEA • 3 lv; S of Taiwan Bank; 21°35′ N, 118°15′ E; depth 1634–1683 m; ZhongSha 2015, stn CP4163; MNHN-IM-2013-59549 to MNHN-IM-2013-59551. Description MEASUREMENTS (holotype). SL 54.1 mm, AL (with canal) 27.3 mm, AL (without canal) 18.0 mm, SW 21.1 mm. SHELL (holotype). Shell large, broad fusiform, thin but strong, with medium high spire, covered by thin yellowish periostracum, greyish-olive in color, with slightly lighter canal. Protoconch and upper teleoconch whorls missing, remaining slightly over 7 whorls. Teleoconch whorls distinctly angled at shoulder, with concave subsutural ramp on all whorls. Distinct, shallow, impressed suture. 19 strong, oblique, narrow axial folds on last whorl, 14 on penultimate one. Folds fade on subsutural, reach lower suture on all whorls. On last whorl folds extend to periphery and shell base. Intervals between folds nearly twice exceed folds’ width on last and penultimate whorls. Distinct sculpture of similar in size, low, slightly wavy cords over entire shell, including subsutural ramp. On subsuturtal ramp cords less pronounced and broader spaced, than on shoulder and shell base. The broadest intervals between cords equal or exceed cords’s width. Numerous, thin, indistinct growth lines. Shell base rounded, strongly convex, rapidly constricting and passing into long rather narrow, straight canal. Medium broad, elongate-oval aperture, poorly differentiated from canal, inner lip weakly concave. Columellar and parietal sides covered by narrow, distinct white callus. Deep, subsutural, broadly arcuate anal sinus extends across subsutural ramp, confluent with large forward extension of outer lip. RADULAE (Fig. 20G; studied in holotype and MNHN-IM-2013-59549, very similar in both specimens). Rather long, comprising about 35 rows of teeth, 7–8 nascent. Marginal teeth duplex, ~410–620 µm in length (3.1–3.4% AL without canal). Major limb narrow lanceolate in dorsal view, strongly 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 4 cox 1 sequences) ‘C’ in site 22, ‘T’ in site 49, ‘C’ in site 421. Remarks The species can reach a shell length of 60 mm. There is considerable interspecific variability, with the canal ranging from narrow to broad, resulting in noticeably different shell outlines. The axial folds are most pronounced in the holotype, where they can be limited to knobs on a shoulder but may become faint and difficult to discern on the last whorl. In specimens of similar size, the number of folds on the last whorl varies between 16 and 21. The holotype closely resembles that of L. luzonica (illustrated in Fig. 24H for comparison, shown at the same scale) and was initially identified as such by Kantor et al. (2018). However, other sequenced specimens exhibit significant differences, such as a wider and visually shorter canal or a slenderer shell (e.g., MNHN-IM-2013-59550, Fig. 24E–F). The spiral sculpture also shows some variation. In some specimens, only the broadest intervals between cords are wider than the cords themselves, while in the specimen MNHN-IM-2013-59549, the intervals are nearly twice as wide as the cords. The new species differs from L. luzonica in having a much larger (60 mm vs 42 mm) and thicker shell, as well as in details in its spiral sculpture (see the Remarks section of L. luzonica for further comparison). Distribution South China Sea, 1634–1707 m.