Scaphander obnubilus, Siegwald & Malaquias, 2025

Scaphander obnubilus View in CoL sp. nov.

( Figs 15 View Figure 15 , 32 View Figure 32 , 33 View Figure 33 ; Table 2)

Scaphander sp.3 — Siegwald et al. 2022.

ZooBank LSID: urn:lsid:zoobank.org:act:68312AEC-383B-431B-A5DD-3609B2342F66

Etymology: Latin, obnubilus ; clouded, concealed. Named for the subtle differences between its shell and the shell of its sister species.

Type material: Australia: Bass Strait , holotype, dissected and sequenced, AM C.482192 , H = 20 mm ; New South Wales, Jervis Commonwealth Marine Reserve , one paratype, dissected and sequenced, AM C.519273 , H = 16 mm .

Other material examined: Australia: Bass Strait, one spc., sequenced, AM C.590969, H = 15 mm.

Diagnosis: Shell ovoid, white. Spiral sculpture composed of sub-rectangular to ovoid punctuated striations. Small, flat spire partly separated from body whorl by a suture widening into a groove along upper part of parietal wall. Outer lip rounded posteriorly, slightly protruding beyond apex. Smooth white callus thickening the parietal wall. Rachidian teeth sub-quadrate, with upper cusps pointing outwards. Prostate cylindrical, separated from penial chamber by short prostatic duct. Penial papilla cylindrical, covered with warts and wrinkles.

Shell ( Fig. 32 View Figure 32 ): Maximum H observed = 20 mm. Shell ovoid. Aperture wide, as long as shell, narrowing towards posterior. Small flat spire of three to four whorls. Suture partly separating the spire from the body whorl, widening into a groove along upper part of the parietal wall. Posterior edge of outer lip joining body whorl immediately below spire in rounded shoulder rising beyond apex. Parietal wall covered with thick, smooth white callus. Spiral sculpture composed of punctuated striations. Punctations ovoid to sub-rectangular, of variable size. Thin, translucent periostracum. Shell white.

Radula ( Fig. 33A–C View Figure 33 ): Radular formula 15 × 1.1.1 (H = 16 mm). Lateral teeth curved, with weak denticulation on inner edge. Rachidian teeth sub-quadrate, with broad cusps pointing sharply outwards on one end.

Digestive tract ( Fig. 33D, E View Figure 33 ): Salivary glands long, thin; surface smooth. Paired gizzard plates sub-triangular to kidney-shaped.

Male reproductive system ( Fig.33F, G View Figure 33 ): Penialchambercylindrical, lined with soft longitudinal ridges between genital opening and prostatic duct. Penial papilla muscular, cylindrical, covered in warts and wrinkles. Penial chamber separated from prostate by thin prostatic duct, widening towards prostate. Prostate cylindrical, rounded at end.

Ecology: Found between 2636 and 2760 m depth. Feeds on foraminifera (present study).

Distribution ( Fig. 15 View Figure 15 ): Australia, between the southern part of New South Wales and the Bass Strait.

Remarks: The shell of S. obnubilus is similar to other spire-bearing species of Scaphander from the Pacific, such as S. grandis , S. meridionalis , S. planeticus , and S. tortuosus . However, the outer lip of S. obnubilus does not form a shoulder against the body whorl as in S. grandis , S. planeticus , and S. tortuosus , but is rounded and rises slightly above the apex instead. The shells of S. meridionalis show remarkable variability ( Fig. 26 View Figure 26 ), but they never depict such a wide and curved aperture as in S. obnubilus . Furthermore, the uncorrected p -distances for COI of these two species range from 5.78% to 6.87%.