Scaphander teramachii ( Habe, 1954 )

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 : 31-32

Scaphander teramachii ( Habe, 1954)

( Figs 19–21 ; Table 2)

Bucconia teramachii Habe, 1954: 307 , pl. 38, figs 1, 2; 1955: 70; 1964: 140, pl. 43, fig. 20.

Scaphander teramachii — Hori 2017: 1087, pl. 386, fig. 3.

Taxonomic history: The species was described under the name Bucconia teramachii , based on shells from Tosa Bay, Japan by Habe (1954), who commented on its similarities with the species Bucconia attenuata (= Scaphander attenuatus ; see S. cancellatus section) from Indonesia (a synonym of S. cancellatus ), but mentioned that the latter had larger, more attenuate shells. Kuroda et al. (1971) transferred the species to the genus Nipponoscaphander with no explanation, and the name N. teramachii was later used to report unidentified Nipponoscaphander species from China ( Guangyu 1997, Qi 2004). More recently, Hori (2017) assigned this species to the genus Scaphander but without any explanation.

Type material: Untraceable.

Material examined: Japan: Tosa Bay, three spcs, two sequenced, one dissected and sequenced, ZMBN 131891, H = 5–6 mm; Nansei Islands, five spcs, one dissected, NSMT Mo-95253, H = 4.1–6 mm; eight spcs, NSMT Mo-95254, H = 1.3– 8.5 mm; East China Sea, west of Takara Islands, three spcs, three sequenced, ZMBN 131888, H = 7–8 mm.

Diagnosis: Shell ovoid to sub-rectangular, dirty white. Spiral sculpture composed of ovoid punctations forming striations. Apex rounded. Posterior edge of outer lip rounded, rising slightly above apex. Rachidian teeth H-shaped. Prostate oval, separated from penial chamber by short prostatic duct. Penial chamber lined with soft longitudinal ridges.

Shell ( Fig. 19 ): Maximum H observed = 31 mm. Shell ovoid to sub-rectangular, only one whorl visible. Aperture wide, as long as shell, narrowing posteriorly. Spire slightly umbilicate in juveniles. Posterior edge of outer lip rounded, protruding slightly beyond apex. Parietal wall covered with white callus; thick, smooth in anterior half; thin to inconspicuous in posterior half. Spiral sculpture composed of punctuated striations. Punctations well defined, ovoid, distinct. Thin, dirty white periostracum. Shell dirty white.

Radula ( Fig. 20A–C ): Radular formula 14 × 1.1.1 (H = 6 mm). Lateral teeth curved, with weak denticulation on inner edge. Rachidian teeth H-shaped, with upper cusps more developed, squarish.

Digestive tract ( Fig. 20D, E ): Salivary glands thin; surface smooth. Paired gizzard plates sub-triangular to kidney-shaped.

Male reproductive system ( Fig.20F, G ): Penial chamber cylindrical, widening towards prostatic duct, lined with soft longitudinal ridges. Muscular penial papilla absent. Penial chamber separated from prostate by short prostatic duct, widening towards prostate. Prostate oval, rounded at end.

Ecology: Found between 100 and 1533 m depth. Feeds on foraminifera and small molluscs (bivalves and gastropods) ( Habe 1964; present study).

Distribution ( Fig. 21 ): Tosa Bay, Japan ( Habe 1954, 1964, Hasegawa and Okutani 2011, Hori 2017; present study) to China Sea ( Hori 2017; present study).

Remarks: As Habe (1954) remarked in the original description of S. teramachii , the adult form of the species bears a strong resemblance to congeneric S. cancellatus , whose posterior edge of the outer lip rises in a more pronounced wing and whose aperture is generally wider. However, it is demonstrated in this study that the shells of S. cancellatus depict great variability (see S. cancellatus section), making the separation of these two species based on shell characters difficult. In addition, both species have similar internal features, such as an eversible penial chamber lined by warts. Despite our efforts, the type material for S. teramachii could not be located and is likely to be untraceable. Two shell labelled as ‘possible’ types are housed at the National Museum of Nature and Science in Tokyo ( NSMT Mo-38721); however, these are larger than the specimen mentioned in the original description ( Habe 1954, Hasegawa and Okutani 2011; present study) and differ slightly in shape from Habe (1954) ’s drawing by being more inflated anteriorly and generally less elongate, with a periostracum orange in colour. The periostracum was originally described as white, which is the same colour observed by us in newly collected material. Based on these features, the shells labelled as ‘possible’ types housed at the NSMT are here assigned to the species S. cancellatus , which was also recorded in Japan (as Bucconia attenuata ) by the original descriptor of S. teramachii ( Habe 1955) .

In this study, it was possible to amplify and sequence DNA only from smaller, probably juvenile, white S. teramachii from Japan. The lack of DNA sequences from the resembling S. cancellatus from Japan hindered a sound comparative study of the shells of the two species, and any differences pointed out between them warrant caution. The name Nipponoscaphander teramachii has been used to report specimens from the South China Sea ( Guangyu 1997, Qi 2004) and the Philippines ( Poppe 2010). However, examination of the illustrations provided in those works revealed that the depicted specimens are not conspecific with S. teramachii , but do belong to the genus Nipponoscaphander . Therefore, the distribution of S. teramachii is here considered to be restricted to Japan.

This species showed higher than average intraspecific variability for COI, with uncorrected p -distances of 0%–3.9%. However, no anatomical differences were observed in the morphological study of these sequenced specimens.

Figures

Figure 19. Shells and SEM image of the shell sculpture of Scaphander teramachii. A, Japan, Tosa Bay (ZMBN 131891, H = 6 mm). B, Japan, East China Sea, west of Takara Island (ZMBN 131888, H = 8 mm). C, Japan, Tosa Bay (ZMBN 131891, H = 6 mm). Scale bar: C = 200 µm.

Figure 20. Anatomical details of Scaphander teramachii. A, radula, Japan, East China Sea, west of Takara (ZMBN 131888, H = 8 mm). B, rachidian teeth (ZMBN 131888, H = 8 mm). C, detail of lateral teeth (ZMBN 131888, H = 8 mm). D, anterior part of digestive tract (ZMBN 131888, H = 8 mm). E, gizzard plates (ZMBN 131888, H = 8 mm). F, male reproductive system, Japan, Nansei Islands (NSMT Mo-95253, H = 6 mm). G, penial chamber lining (ZMBN 131888, H = 8 mm). Scale bars: A = 100 µm; B = 20 µm; C = 10 µm; D = 500 µm; E, F = 1 mm; G = 200 µm.

Figure 21. Geographical distribution of Scaphander semicallus, Scaphander solomonensis, and Scaphander teramachii. Geographical records are based on studied material and reliable literature records.