Sibogasyrinx 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 : 30

Sibogasyrinx pyramidalis ( Schepman, 1913)

Fig. 3H–I

Surcula pyramidalis Schepman, 1913: 423 , pl. 27, fig. 10a–b.

Leucosyrinx (Sibogasyrinx) pyramidalis – Powell 1969: 343 (23-411), pl. 264 figs 1–5. — Shuto 1970: 171, pl. 11 figs 10–13. — Medinskaya 1999: 176–177, figs 3, 16d–e.

Sibogasyrinx pyramidalis – Kantor et al. 2018: 57–58, figs 5e–n, 6c–d.

Material examined

Holotype TIMOR SEA • 10°48.6′ S, 123°23.1′ E; depth 918 m; ZMA.MOLL.136836 .

Remarks

Kantor et al. (2018) provided illustrations of shells and radulae of sequenced specimens of what they considered to be S. pyramidalis . The specimens studied were collected off Luzon Island ( Philippines) and in the central South China Sea (= PSH 2, S. cf. pyramidalis 1). The shell outline of these specimens of this generally variable species matched the illustration of the holotype, which was not examined. The present molecular analysis revealed that there are two molecularly distinct but morphologically cryptic species that match the description and illustrations of the holotype of S. pyramidalis ( Schepman 1913: fig. 10a–b; Shuto 1970: pl. 11, figs 10–13; Fig. 3H–I herein). The second species, not discussed in Kantor et al. (2018), was collected in the Bismarck Sea and also displays significant shell variability (= PSH 1, S. cf. pyramidalis 2). The geographic ranges of these two PSHs do not include the type locality of S. pyramidalis (Timor Sea, Pulau Rote Island). There are two possible explanations for this: one of our species represents the true S. pyramidalis , or S. pyramidalis is a third species and both of ours are new to science. Unfortunately, this can only be resolved by sequencing topotypic material from the Timor Sea. In order to not add to the taxonomic ambiguity, we presently refrain from taking any taxonomic decision, but for the sake of convenience refer here to our molecular species as S. cf. pyramidalis 1 (= S. pyramidalis sensu Kantor et al. 2018 ) and S. cf. pyramidalis 2.

Medinskaya (1999: fig. 16d–e) illustrated the radula of a specimen from Indonesia (Tanimbar I., 08°36′ S, 131°33′ E, 699– 676 m) collected close to the type locality. Unfortunately, the shell was not illustrated and the identification of the specimen cannot be confirmed. Its radula is identical to that of S. cf. pyramidalis 1 and S. cf. pyramidalis 2 ( Kantor et al. 2018: figs 5c–d, 6a–b; Fig. 4A–D herein).

Figures

Fig. 3. Sibogasyrinx pyramidalis (Schepman, 1913) complex. A–G. Sibogasyrinx cf. pyramidalis 1. A–C. South China Sea, MNHN-IM-2013-44605, SL 65.2 mm. D–F. Philippines, MNHN- IM-2009-13451, SL 46.8 mm. G. South China Sea, MNHN-IM-2013-44574, SL 53.9 mm. H–I. Surcula pyramidalis Schepman, 1913, holotype, ZMA.MOLL.136836, SL 45 mm (photos by K. Hasegawa, copyright Naturalis, Leiden). J–Q. Sibogasyrinx cf. pyramidalis 2, Papua New Guinea. J–L. MNHN- IM-2013-19745, SL 65.2 mm.M–O. MNHN-IM-2009-17000, SL 59.2 mm. P. MNHN-IM-2009-16973, SL 41 mm. Q. MNHN-IM-2009-16988, SL 43 mm. R–T. Sibogasyrinx archibenthalis (Powell, 1969), holotype, USNM 238773, SL 41.8 mm. All shells to same scale.

Fig. 4. Radulae of species of Sibogasyrinx Powell, 1969. A–B. S. cf. pyramidalis (Schepman, 1913) 1, MNHN-IM-2009-13451 (shell seen on Fig. 3D–F). A. Part of radula with marginal teeth not fully formed; white arrows indicate teeth that are not fully folded longitudinally (ae = anterior tooth edge; pe = posterior tooth edge). B. Part of radula with fully formed marginal teeth. C. S. cf. pyramidalis 2, MNHN-IM-2009-16972. D. S. cf. pyramidalis 2, MNHN-IM-2009-17000 (shell seen on Fig. 3M–O). E. S. subula sp. nov., MNHN-IM-2007-17703. F. S. subula sp. nov., MNHN-IM-2009-13568 (shell seen on Fig. 6H–I).