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

Leucosyrinx zucconi sp. nov. urn:lsid:zoobank.org:act: 6BB71F3B-B868-491C-A039-72810DAC1FB3 Figs 5D, 6 Etymology The species is named after Dario Zuccon, member of the ERC “HYPERDIVERSE” team and long-term member of the MNHN team, as a recognition of his many years of indispensable efforts in sequence production. Material examined Holotype (sequenced) SOLOMON ISLANDS • Santa Isabel I.; 8°47′ N, 159°40′ E; depth 645–840 m; SALOMON 2, stn CP2181; MNHN-IM-2009-16820. Other material (all sequenced) SOLOMON ISLANDS • 1 lv; 7°28′ N, 156°14′ E; depth 1000–1050 m; SALOMON 2, stn CP2251; MNHN-IM-2009-13595 • 2 lv; 7°28′ N, 156°17′ E; depth 1059–1109 m; SALOMON 2, stn CP2252; MNHN-IM-2009-13574, MNHN-IM-2009-13575 • 1 lv; Santa Isabel I.; 8°47′ N, 159°38′ E; depth 762–1060 m; SALOMON 2, stn CP2182; MNHN-IM-2009-16765. Description MEASUREMENTS (holotype). SL 71.9 mm, AL (with canal) 37.3 mm, AL (without canal) 23.0 mm, SW 25.4 mm. SHELL (holotype). Large, fusiform, with a high spire, uniformly greyish in color, strong, with very thin greyish, tightly adhering smooth periostracum. 9+ teleoconch whorls, uppermost whorls and protoconch missing. Teleoconch whorls distinctly angled at shoulder, with weakly concave subsutural ramp. Shallow but distinct, impressed, slightly wavy suture. Teleoconch whorls, except last one with strong, oblique, medium broad, and rounded axial folds, absent on subsutural ramp, slightly weaken towards lower suture, 23 folds on penultimate and antepenultimate whorls. Folds fade at border between penultimate and last whorl. Last whorl shoulder distinctly angulated. Spiral sculpture of low, very narrow, but distinct strongly wavy cords over entire shell. 18 cords on subsutural ramp of last whorl and 20 of penultimate whorl. Numerous thin growth lines, also prominent on subsutural ramp. Shell base weakly evenly convex, smooth transition to long, straight canal. Narrow, elongate-oval aperture, poorly differentiated from canal aperture. Inner lip slightly convex, nearly straight. Columellar and parietal sides with narrow, distinct callus. Moderately deep, subsutural, broadly arcuate anal sinus extends across subsutural ramp, confluent with large forward extension of outer lip. RADULA (Fig. 5D) (studied in holotype). Marginal teeth duplex, ~450 µm in length, relatively short (1.95% of AL without canal), medium broad. Major limb lanceolate in strict dorsal view, slightly curved. Accessory limb more than twice as narrow, ~0.8 of total tooth length, inserted into distinct and rather deep socket on dorsal side of major limb. DNA diagnosis (based on 2 cox 1 sequences) ‘C’ in site 14, ‘G’ in site 256, ‘T’ in site 499, ‘C’ in site 581, ‘C’ in site 586. Remarks The holotype is the largest specimen; the younger, nearly twice as small, has pagoda-like shape of the spire due to more distinct shoulder. The combination of the broad shell, pagodiform in younger specimens with more than 20 axial folds per whorl distinguish the species from other congeners. Distribution Solomon Is., 645–1059 m.