Sibogasyrinx elbakyanae Kantor, Puillandre & Bouchet, 2021

Kantor, Yuri I. & Puillandre, Nicolas, 2021, Rare, deep-water and similar: revision of Sibogasyrinx (Conoidea: Cochlespiridae), European Journal of Taxonomy 773, pp. 19-60 : 54-55

Sibogasyrinx elbakyanae Kantor, Puillandre & Bouchet sp. nov. (= PSH 4)

urn:lsid:zoobank.org:act:F9B671D9-4F84-4DF4-BAA0-3EF30AF06512

Fig. 12E–H

Diagnosis

Shell small, reaching 27.5 mm in length, fusiform, subsutural ramp strongly concave with distinct, broadly-spaced spiral cords and dense subsutural nodules. Axial sculpture of distinct opisthocline ribs extending to shell periphery. Spiral sculpture of distinct cords on and below shoulder.

Etymology

Philippe Bouchet joins us in dedicating this species to honor Alexandra Elbakyan, creator of the famous sci-hub portal.

Material examined

Holotype SOLOMON ISLANDS • S of Malaita I.; 09°55′ S, 161°33′ E; depth 1136–1750 m; SALOMONBOA 3, stn CP2817; MNHN-IM-2009-16834 .

Description (holotype)

MEASUREMENTS. SL 27.3 mm, AL (with canal) 15.0 mm, AL (without canal) 9.6 mm, SW 8.9 mm.

SHELL. Moderately thick, except for fragile outer aperture lip, partially chipped; fusiform, with high spire and long, narrow, straight siphonal canal. Protoconch eroded and partially decollated, thus rendering whorl count and measurements impossible. Teleoconch whorls strongly angled at shoulder, about 8 whorls in total. Suture deeply impressed, subsutural ramp moderately broad, strongly concave. Subsutural region with a row of dense, distinct, sigmoidal axial ribs that correspond in shape to upper parts of thickened growth lines and form small rounded nodules at intersections with spiral cords. Rib counts on uppermost whorls not possible due to shell surface erosion, about 24 on antepenultimate whorl, 27 on penultimate and 34 on last whorl. Subsutural ramp with thin but distinct spiral cords, 3 on first preserved teleoconch whorl and 5 on last three whorls, one immediately subsutural followed by another with interval about three times cord width, then three more closely spaced ones separated from second cord by an interval of about five times cord width. Upper two cords forming nodules at intersections with axial ribs. Shoulder with pronounced, thickened, opisthocline axial ribs on all teleoconch whorls, about 12 on upper whorls, including penultimate one and 14 on last whorl. Ribs extending to abapical suture on spire whorls, intersected by spiral cords, uppermost 2–3 very thin and closely spaced followed by 5–8 more broadly spaced. Last whorl with about 35 cords on shoulder and below, including 15 on canal. Cords narrow and separated by intervals 1–3 times the width of cords on axial ribs on shoulder, more broadly spaced on shell base and canal. Shell base gradually narrowing towards narrow, moderately long, nearly straight siphonal canal. Aperture narrow, constricted posteriorly, with moderately broad, thin parietal callus, outer lip partially broken, with rounded angle at shoulder, weakly convex below shoulder and weakly concave at transition to canal. Anal sinus shallow, subsutural, broadly arcuate. Shell base off-white, upper part of last whorl and teleoconch whorls very light yellow. Periostracum thin, persisting in intervals between cords and ribs.

ANATOMY. Adult male, penis long, gradually narrowing towards tip, obliquely truncated at tip with a small but rather long conical papilla, surrounded by circular fold. Proboscis not long, conical, proboscis retractors not defined, entire posterior part of proboscis base muscular. Salivary glands fused, small. Single oval accessory salivary gland present at level of anterior part of proboscis. Venom gland large, thick and strongly convoluted, very constricted before opening into oesophagus within nerve ring. Muscular bulb moderately large.

RADULA. Minute, comprising about 15 rows of teeth. Radula length 650 μm (6.8% of AL without canal), width up to 100 μm (1% of AL without canal). Central tooth present, with long cusp. Marginal teeth trough-shaped. Due to poor preparation it was impossible to study tooth morphology in detail.

Remarks

This species is most similar to Sibogasyrinx filosa , but differs in having a more stout shell with a relatively shorter canal, fewer, more distinct axial ribs on the shoulder (35 vs 46 on last whorl), and thinner, more widely spaced spiral cords. In shell outline the new species resembles some species of Leucosyrinx , particularly Leucosyrinx verrillii (Dall, 1881) ( Fig. 13A–C ), but differs in its smaller size, less numerous shoulder nodules and radular morphology.

Distribution

Known only from the type locality.

Figures

Fig. 12. A–D. Sibogasyrinx pagodiformis sp. nov. A–B. Solomon Islands, holotype, MNHN- IM-2009-16825, SL 28.8 mm. C–D. Vanuatu. MNHN-IM-2009-11327, SL 24.3 mm. E–H. Sibogasyrinx elbakyanae Kantor, Puillandre & Bouchet sp. nov., holotype, Solomon Islands, MNHN-IM-2009-16834, SL 27.3 mm. H. Enlarged fragment of penultimate and antepenultimate whorls. A–G to same scale.

Fig. 13. Shells of species of Leucosyrinx Dall, 1889. A–B. Leucosyrinx verrillii (Dall, 1881), French Guiana, MNHN-IM-2013-56840, SL 25.1 mm. C. L. verrillii, French Guiana, MNHN-IM-2013-56288, SL 31.9 mm (radula seen on Fig. 11C). D–E. Leucosyrinx sp. G. D. Papua New Guinea, MNHN- IM-2009-17089, SL 32.2 mm (radula seen on Fig. 11E). E. Bismarck Sea, MNHN-IM-2013-19689, SL 47.3 mm.F. Leucosyrinx sp. D, Solomon Islands, MNHN-IM-2009-16769, SL 25 mm.G. Leucosyrinx sp. E, Madagascar, MNHN-IM-2009-16897, SL 46.1 mm. H. Leucosyrinx sp. A, Philippines, MNHN- IM-2007-42445, SL 34.1 mm. I. Leucosyrinx sp. B, Solomon Islands, MNHN IM-2009-16764, SL 29.9 mm. J. Leucosyrinx sp. C, Solomon Islands, MNHN-IM-2007-42503, SL 41.2 mm (radula seen on Fig. 11F). K. Leucosyrinx sp. F, Coral Sea, Chesterfield Plateau, MNHN-IM-2007-17846, SL 27.3 mm (radula seen on Fig. 11D). All shells to same scale.