Leucosyrinx claviforma ( Kosuge, 1992 )

Kantor, Yuri I., Fedosov, Alexander & Puillandre, Nicolas, 2025, Revision of the Indo-Pacific species of the genus Leucosyrinx Dall, 1889 (Neogastropoda: Conoidea: Pseudomelatomidae), European Journal of Taxonomy 999, pp. 1-126 : 32-34

Leucosyrinx claviforma ( Kosuge, 1992)

Figs 10B–C , 12A–F

Comitas claviforma Kosuge, 1992: 165 , pl. 58 figs 7–8.

Leucosyrinx claviforma – Sysoev 1996: 11, fig. 28.

Type material

Holotype

WESTERN AUSTRALIA • off Port Hedland , 17°58′ S, 118°25′ E; depth 376 m; WAM 45-86 .

Material examined (all sequenced)

BISMARCK SEA • 1 lv; N Bagabag Is; 4°45′ S, 146°12′ E; depth 456–582 m; PAPUA NIUGINI, stn CP3978; MNHN-IM-2013-9614 .

PAPUA NEW GUINEA • 1 lv; Woodlark Is. ; 9°07′ S, 152°14′ E; depth 473–491 m; BIOPAPUA, stn DW3738; MNHN-IM-2009-17180 • 1 lv; submarine mountains off Bougainville; 5°33′ S, 154°00′ E; depth 369–377 m; BIOPAPUA, stn DW3745; MNHN-IM-2013-52048 • 1 lv; New Ireland; 2°23′ S, 150°37′ E; depth 416–535 m; KAVIENG 2014, stn CP4437; MNHN-IM-2013-58303 • 2 lv; New Ireland; 2°15′ S, 150°14′ E; depth 450–474 m; KAVIENG 2014, stn CP4446; MNHN-IM-2013-58380, MNHN-IM-2013-58382 .

SOLOMON SEA • 2 lv; SE of Tuam Is ; 6°04′ S, 148°09′ E; depth 460–528 m; PAPUA NIUGINI, stn CP4007; MNHN-IM-2013-9729, MNHN-IM-2013-9731 • 1 lv; SE of Tuam Is ; 6°04′ S, 148°10′ E; depth 500–555 m; PAPUA NIUGINI, stn CP4008; MNHN-IM-2013-9725 • 3 lv; SE of Tuam Is ; 6°04′ S, 148°12′ E; depth 500–575 m; PAPUA NIUGINI, stn CP4009; MNHN-IM-2013-19932, MNHN- IM-2013-19934, MNHN-IM-2013-9730 .

Description

SHELL. Medium sized, reaching 38+ mm, thin but solid, narrow fusiform, with very high spire, light yellowish in color. Paucispiral small protoconch of nearly 2 convex evenly rounded smooth whorls. Whorls distinctly angulated on shoulder, with distinctly concave subsutural ramp, last whorl can be weakly roundly angular at transition to shell base. Shallow and impressed suture. Strong, oblique, broad, and rounded axial folds on shoulder of teleoconch whorls. Folds fade on subsutural ramp, strongly weaken towards lower suture, disappear shortly below shoulder on last whorl. Number of folds per whorl increasing with shell size, 17–18 on last whorl. Rather distinct spiral sculpture of closely spaced, low, rounded, straight on subsutural ramp and wavy below suture cords over entire shell. Shell base strong to weakly convex, smooth transition to long, straight canal. Narrow, elongate-oval aperture, poorly differentiated from canal. Deep, subsutural, broadly arcuate anal sinus extends across subsutural ramp, confluent with large forward extension of outer lip.

RADULA ( Fig. 10B–C ; studied in two specimens, MNHN-IM-2013-58303 and MNHN-IM-2013-52048). Short, comprises around 25 rows of teeth, 8–9 nascent. Morphologically similar in both specimens. Marginal teeth duplex, relatively long, ~205–290 µm (4.8–6.2% AL without canal). Major limb medium narrow lanceolate in dorsal view, curved. Accessory limb narrow, constitutes less than half of tooth width, ~0.8 of total tooth length, inserted into distinct medium deep socket on dorsal side of major limb.

DNA diagnosis (based on 12 cox 1 sequences)

‘C’ in site 70, ‘G’ in site 97, ‘C’ in site 139, ‘C’ in site 586.

Remarks

The species was described based on a single dead-collected and strongly worn shell ( Fig. 12A ), lacking protoconch and upper teleoconch whorls with SL 38.1 mm. Sequenced specimens at our disposal originated from Papua New Guinea and the Solomon and Bismarck seas from depths of 370– 500 m. Although our specimens are significantly smaller (reaching 24.3 mm vs 38.1 mm in the holotype), conchologically they are rather similar to the holotype in a characteristic narrow fusiform shell with a very high spire and a prominent angulation of the shoulder. The shell shape and prominence of the axial folds are moderately variable in the species. Our examined specimens with SL 19–24 mm were already adults judging from their fully developed very long penises.

Another similar species is Leucosyrinx granuloplicata ( Kosuge, 1992) , also from Western Australia at depths of 276– 497 m. It differs in more pronounced and broader spaced folds on the whorl shoulders ( Fig. 12G ). Since the variability of L. granuloplicata is not known, it is not possible to decide whether it is an extreme form of L. claviforma , or a distinct species. Presently, we consider it as a valid species.

Distribution

Western Australia, Maldive Is. ( Sysoev 1996), Papua New Guinea, Solomon and Bismarck seas (this study), 376–1170 m.

Figures

Fig. 10. Radulae of species of Leucosyrinx Dall, 1889. A. L. oliverioi sp. nov., holotype, MNHN- IM-2007-17928, SL 37.5 mm.B–C. L. claviforma, MNHN- IM-2013-58303, SL 19.1 mm.B. Dorsal view of the radula membrane. C. Bending plane, showing marginal teeth in different views. D–E. L. urbanae sp. nov., MNHN-IM- 2009-17215, SL 14.1 mm. D. Dorsal view of the radula membrane. E. Bending plane, showing marginal teeth in different views. F. Leucosyrinx sp. 24, MNHN-IM-2013-66098, SL 21.6 mm. G. Leucosyrinx sp. 22, MNHN-IM-2013-48155, SL 24.2 mm. H. Leucosyrinx sp. 8, MNHN-IM-2009-29323, SL 20.1 mm. I. L. boiteuxi sp. nov., MNHN-IM-2013-19848, SL 46.5 mm. Scale bars = 100 µm.

Fig. 12. A–F. Leucosyrinx claviforma (Kosuge, 1992). A. Holotype, WAM 45-86, SL 38 mm (courtesy of WAM). B–D. MNHN-IM-2013-19932, Solomon Sea, 500–575 m, SL 24.3 mm. E. MNHN- IM-2013-9614, Bismarck Sea, 456–582 m, SL 19.2 mm. F. MNHN-IM-2013-58303, Papua New Guinea, 416–535 m, SL 19.1 mm. G. Leucosyrinx granuloplicata (Kosuge, 1992), holotype, WAM S14436 SL 35.3 mm (courtesy of WAM). H. Leucosyrinx sp. 12, MNHN-IM-2007-42637, Vanuatu, SL 22.9 mm. I–M. Leucosyrinx gaelae sp. nov. I–K. MNHN-IM-2009-17135, holotype, SL 21.9 mm. L. MNHN-IM-2009-16996, Papua New Guinea, 788–805 m, SL 25.3 mm. M. MNHN-IM-2009-16997, Papua New Guinea, 788–805 m, SL 21.8 mm. All shells at the same scale.