Sibogasyrinx cf. pyramidalis ( Schepman, 1913 )

Kantor, Yuri I. & Puillandre, Nicolas, 2021, Rare, deep-water and similar: revision of Sibogasyrinx (Conoidea: Cochlespiridae), European Journal of Taxonomy 773, pp. 19-60 : 32-35

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Sibogasyrinx cf. pyramidalis ( Schepman, 1913 )


Sibogasyrinx cf. pyramidalis ( Schepman, 1913) 2 (= PSH 1)

Figs 3J–Q View Fig , 4C–D View Fig , 5 View Fig

Material examined (all sequenced)

PAPUA NEW GUINEA • 2 lv; off Manus I.; 02°16′ S, 147°29′ E; depth 679–685 m; BIOPAPUA, stn CP3689; MNHN-IM-2009-16972 , MNHN-IM-2009-16973 GoogleMaps 1 lv; N of Rabaul; 04°04′ S, 151°56′ E; depth 585–601 m; BIOPAPUA, stn CP3671; MNHN-IM-2009-16988 GoogleMaps 1 lv; N of Rabaul; 04°04′ S, 151°50′ E; depth 702–724 m; BIOPAPUA, stn CP3672; MNHN-IM-2009-17000 GoogleMaps 1 lv; Bismarck Sea , N of Long I.; 05°11′ S, 147°03′ E; depth 688 m; PAPUA NIUGINI, stn CP3981; MNHN-IM-2013-19716 GoogleMaps 1 lv; Bismarck Sea , N of Long I.; 05°10′ S, 147°03′ E; depth 724 m; PAPUA NIUGINI, stn CP3982; MNHN-IM-2013-19745 GoogleMaps 1 lv; Bismarck Sea , NW of Long I.; 05°12′ S, 146°59′ E; depth 470–508 m; PAPUA NIUGINI, stn DW3983; MNHN-IM-2013-19768 GoogleMaps 1 lv; New Ireland, 02°42′ S, 150°02′ E; depth 827–966 m; KAVIENG 2014, stn CP4483; MNHN-IM-2013-58845 GoogleMaps .


MEASUREMENTS (largest specimen). SL 65.2 mm, AL (with canal) 34.7 mm, AL without canal 22.9 mm, SW 18.0 mm.

SHELL. Extremely similar to that of Sibogasyrinx cf. pyramidalis 1. The only slight difference is the larger number of spiral cords crossing the shoulder nodules. Penultimate whorl of S. cf. pyramidalis 1 with 5–6 cords (increasing with SL), 6–8 in S. cf. pyramidalis 2.

ANATOMY (n = 2, MNHN-IM-2009-16972, MNHN-IM-2009-17000). Head with long, cylindrical tentacles, rounded on tips with closely spaced bases, eyes absent.One specimen(MNHN-IM-2009-17000) male, with long penis with obliquely truncated tip. Seminal papilla occupies entire tip and is surrounded by circular fold. Proboscis long, coiled, with broad conical base, occupied by large bulbous buccal mass, spanning posterior ¼ of proboscis and protruding backwards from proboscis. Proboscis sheath with very thin transparent walls. Remaining anterior part of proboscis narrow, gradually diminishing in diameter towards its tip. Proboscis retractors well defined, powerful and numerous, attached to posteriormost edge of rhynchodeum. Radular sac and short oval odontophore situated on right side of buccal mass, posterior to rear of proboscis. Oesophagus adjoining buccal mass slightly constricted and forming a moderately long loop before passing through nerve ring. Salivary glands irregularly shaped, covering dorsal portion of nerve ring. Accessory salivary gland not traced. Venom gland thick, long, strongly convoluted, opens dorsally into oesophagus, immediately posterior to nerve ring ( Fig. 5B View Fig ). Muscular bulb oval, of moderate size, situated to the right of oesophagus.

RADULA (n = 2; MNHN-IM-2009-16972, MNHN-IM-2009-17000). Comprising approximately 40 rows of teeth, 15 nascent, short, length (measured only in MNHN-IM-2009-16972) ca 1.7 mm (14% of AL without canal). Radula width up to 300 μm (2.5% of AL without canal). Shape of teeth very similar to that of Sibogasyrinx cf. pyramidalis 1, central tooth has less rounded posterior margin and in one specimen (MNHN-IM-2009-17000, Fig. 4D View Fig ) the cusp is obtuse.


Despite the similarities in shell and radular morphology, Sibogasyrinx cf. pyramidalis 1 and Sibogasyrinx cf. pyramidalis 2 are clearly distinct from a molecular perspective. One morphological character of the foregut that separates the two species is the presence of an accessory salivary gland in the former.


The confirmed distribution is Papua New Guinea, at 585– 827 m.