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

Leucosyrinx floraecharlottae sp. nov. urn:lsid:zoobank.org:act: ADDB5B90-B92A-4419-826D-25A8EC49C954 Figs 4A–F, 5A Etymology The species is named after Flora and Charlotte, the daughters of Tanya Karagyozova, the project manager of the ERC project HYPERDIVERSE. Material examined Holotype (sequenced) SOLOMON SEA • Vitiaz Strait; 6°00′ S, 147°36′ E; depth 706–715 m; PAPUA NIUGINI, stn CP3995; MNHN-IM-2013-19852. Other material (all sequenced) PAPUA NEW GUINEA • 2 lv; 8°14′ S, 150°32′ E; depth 760–769 m; BIOPAPUA, stn CP3736; MNHN-IM-2009-17046, MNHN-IM-2009-17052 • 1 lv; 9°14′ S, 152°18′ E; depth 694–766 m; BIOPAPUA, stn CP3741; MNHN-IM-2009-17050 • 1 lv; New Britain, north of Rabaul; 4°4′ S, 151°50′ E; depth 702–724 m; BIOPAPUA, stn CP3672; MNHN-IM-2009-17133. Description MEASUREMENTS (holotype). SL 29.2 mm, AL (with canal) 13.3 mm, AL (without canal) 8.9 mm, SW 9.1 mm. SHELL (holotype). Medium-sized, fusiform, with high spire, fragile, of uniform light tan in color. 9.75 teleoconch whorls. Paucispiral protoconch of 1.5 rounded whorls, flattened on top. Protoconchteleoconch transition indistinct due to erosion, marked by appearance of axial ribs. Teleoconch whorls roundly angled at shoulder, with weakly concave subsutural ramp. Shallow, impressed, slightly wavy suture. 17 strong, oblique, short, broad, rounded axial folds on body whorl, 14 on penultimate whorl. Folds fade on subsutural ramp, weaken towards lower suture, disappear at body whorl periphery. Folds closer spaced on upper teleoconch whorls, on last whorl intervals narrower than folds. Weak spiral sculpture of low, rounded, indistinct narrow cords over entire shell. Numerous, thin growth lines, prominent on subsutural ramp. Shell base weakly convex, smooth transition to long, straight canal. Narrow, elongate-oval aperture, poorly differentiated from canal. Inner lip slightly convex. Columellar and parietal sides with narrow, distinct callus, lighter than remaining last whorl. Moderately deep, subsutural, broadly arcuate anal sinus extends across subsutural ramp, confluent with large forward extension of outer lip. RADULA (Fig. 5A; studied in holotype). Short, 32 rows of teeth, 11–12 nascent. Central formation reduced to inconspicuous folds of radular membrane. Marginal teeth duplex, ~410 µm in length (4.6% of AL without canal). Anterior part of tooth dorso-ventrally flattened, with sharp cutting edges in lateral view. Major limb narrowly lanceolate, slightly curved. Accessory limb nearly twice as narrow, ~0.75 of total tooth length, inserted into shallow but distinct socket on dorsal side of major limb. DNA diagnosis (based on 5 cox 1 sequences) ‘A’ in site 220, ‘C’ in site 448, ‘C’ in site 598. Remarks The largest specimen attains SL 32.7 mm. Leucosyrinx floraecharlottae sp. nov. is somewhat variable in shell slenderness, from nearly biconic in holotype to medium-broad fusiform. The holotype of the new species bears a resemblance to L. verrillii (Dall, 1881), the type species of the genus from the Atlantic, in terms of its shell shape and sculpture pattern. However, it differs in having a generally slenderer and smaller shell with much less pronounced spiral sculpture. Another similar species is L. breviplicata (E.A. Smith, 1899), which differs in much more pronounced and broadly-spaced spiral cords. The molecular phylogenetic analysis has demonstrated that these two species are not closely related to L. floraecharlottae sp. nov. Leucosyrinx floraecharlottae sp. nov. demonstrates close resemblance to L. lemarcisi sp. nov., and to a lesser extent to L. ringevali sp. nov., L. farhatorum sp. nov. and L. rattiae sp. nov., all of them not phylogenetically related to L. floraecharlottae. For the morphological differences see remarks of the corresponding species. Distribution Papua New Guinea, 694– 760 m.