Scaphander tortuosus, Siegwald & Malaquias, 2025

Siegwald, Justine & Malaquias, Manuel António E., 2025, Bringing light into deep-sea biodiversity: a systematic revision and molecular phylogeny of the genus Scaphander Montfort, 1810 (Gastropoda: Cephalaspidea), with a focus on the Indo-Pacific, Zoological Journal of the Linnean Society 203, pp. 1-60 : 42

Scaphander tortuosus nom. nov.

( Figs 14 , 15 ; Table 2)

Meloscaphander sibogae Schepman, 1913: 464 , pl. 31, figs 5–9. Scaphander sibogae — Chaban et al. 2019a: 397.

ZooBank LSID: urn: lsid::zoobank.org:act: 19B569B7-0264- 448C-AD90-E151A2AAB9AB

Etymology: Latin, tortuosus ; convoluted. Named for the complexity of its taxonomic history and its visible spire.

Taxonomic history: Schepman (1913) introduced the genus Meloscaphander for this species, which he described as M. sibogae , based on a single specimen from Indonesia, collected during the Siboga expedition . He described an anatomy very similar to Scaphander , but included the species in a separate genus owing to a different shell shape with a visible spire. Chaban et al. (2019a) synonymized Meloscaphander with Scaphander , rendering Scaphander sibogae ( Schepman, 1913) [= M. sibogae Schepman, 1913 ] an unavailable homonym name of Scaphander sibogae Schepman, 1913 , given that the previous names have no synonyms available (see S. sibogae and S. cancellatus sections for complementary information and discussion). Therefore, in accordance with the principle of priority ( ICZN 1999a: art. 23.3.5) and rules for replacement of junior homonyms ( ICZN 1999b: art. 60.3), we here introduce the replacement name Scaphander tortuosus nom. nov. for Meloscaphander sibogae Schepman, 1913 . Following recommendation 60A ( ICZN 1999a,b), the type material of Meloscaphander sibogae Schepman, 1913 is maintained as the type material of S. tortuosus nom. nov.

Type material: Meloscaphander sibogae Schepman, 1913 — Indonesia: Banda Sea , Sulawesi, Siboga expedition , station 221, 6°24 ʹ 00"S, 124°39 ʹ 00"E, 2798 m, holotype, ZMA. MOLL.136944, H = 16 mm, images seen ( Fig. 14B ).

Diagnosis: Shell ovoid, yellowish, wider in upper half, with small, slightly raised spire. Spiral sculpture composed of punctuated striations.

Shell ( Fig. 14 ): Maximum H observed = 16 mm. Shell ovoid, wider towards posterior end. Aperture wide, nearly as long as body whorl, narrowing posteriorly. Small raised spire of four whorls. Posterior edge of outer lip joining body whorl immediately below spire in soft shoulder. Parietal wall covered with thick, smooth white callus. Spiral sculpture composed of punctuated striations. Punctations ovoid, in rows of variable size.

Radula: Lateral teeth curved, with fine denticulation on one of the edges ( Schepman 1913).

Digestive tract: Paired gizzard plates subquadrate, with rounded corners ( Schepman 1913).

Male reproductive system: Unknown.

Ecology: Found at 2798 m.

Distribution ( Fig. 15 ): Banda Sea, off Southeast Sulawesi Island, Indonesia ( Schepman 1913).

Remarks: To our knowledge, only one representative (the holotype) of the species has ever been sampled. It shares the visible spire of S. grandis and S. imperceptus (both also originally described under the genus Meloscaphander ), S. meridionalis , and Scaphander obnubilus . However, considering the variability of shells observed in those species, only the study of additional shells, anatomical details, and ideally DNA sequences could clarify the status of this species.

Figures

Figure 14. Shell of Scaphander planeticos (A), Scaphander tortoosos (B), and Scaphander imperceptos (C, D). A, Northern Pacific Ocean, north of Marquesas Islands (holotype, Scaphander (Sabatina) planeticos, USNM 110748, H = 8 mm, images courtesy of the USNM). B, Indonesia, Sulawesi (holotype Meloscaphander sibogae, ZMA.MOLL.136944, H = 16 mm; images taken by K.Hasegawa and courtesy of Naturalis Biodiversity Center). C, Northeastern Atlantic, northeast of the Azores (syntype, Bolla milleponctata, MNHN-IM-2000-27696, H = 14.8 mm, images courtesy of the MNHN). D, Northeastern Atlantic, off Mauritania (holotype, Meloscaphander imperceptos, MNHN-IM-2000-27680, H = 19.3 mm, images courtesy of the MNHN).

Figure 15. Geographical distribution of Scaphander grandis, Scaphander meridionalis, Scaphander obnubilus, Scaphander planeticos, and Scaphander tortoosos. Geographical records are based on studied material and reliable literature records.