Scaphander otagoensis Dell, 1956

Scaphander otagoensis Dell, 1956 View in CoL

( Figs 8 View Figure 8 , 22 View Figure 22 , 23 View Figure 23 ; Table 2)

Scaphander otagoensis Dell, 1956: 143–144 View in CoL , fig. 208; Powell 1979, 84; Lörz et al. 2012: 41.

Scaphander cf. otagoensis View in CoL 1— Siegwald et al. 2022.

Taxonomic history: Scaphander otagoensis was described by Dell (1956) from shells collected off southern regions of the North and South Islands of New Zealand.

Type material: Scaphander otagoensis Dell, 1956 — New Zealand: off Otago Peninsula, Karitane Canyon, Portobello Alert station 54-17, 45°37’30”S, 171°06’00”E, 475–640 m, holotype, MNZ M.9141 , H = 13.6 mm, images seen ( Fig. 22A, G View Figure 22 ) GoogleMaps ; six paratypes, MNZ M.9140, H = 4–7 mm, images seen ; Taiaroa Canyon, Alert, station B.S.190 , 45°45’24”S, 171°05’00”E, 549 m, one paratype, MNZ M.10565 , H = 9 mm, images seen ( Fig. 22B View Figure 22 ) GoogleMaps .

Other material examined: New Zealand: North Island, eastnortheast of Cape Palliser, head of Pahaua Canyon, 10 spcs, two dissected and sequenced, one dissected, MNZ M.301800, H = 21–27 mm; east-southeast of Cape Palliser, seven spcs, two sequenced, MNZ M.301817, H = 18–28 mm; five spcs, one dissected and sequenced, NIWA 63032, H = 25–31 mm; northwest of Chatham Islands, one spc., sequenced, NIWA 30182, H = 10 mm; Western Chatham Rise, northeast of Mernoo Bank, four spcs and 22 sh., two dissected, MNZ M.059714, H = 6–37 mm; South Island, southeast of Cape Campbell, two spcs, one sequenced, NIWA 63804, H = 17, 26 mm.

Diagnosis: Shell elongate, covered by thick, pale orange to brownish periostracum. Spiral sculpture composed of variable rows of rectangular punctations. Spire concealed; posterior edge of outer lip rising above apex. Rachidian teeth sub-rectangular, elongate. Prostate cylindrical. Penial papilla absent. Penial chamber bulged and lined with soft warts around prostatic duct entrance.

Shell ( Fig. 22 View Figure 22 ): Maximum H observed = 37 mm. Shell elongate to pyramidal, only one whorl visible. Aperture as long as shell, narrowing posteriorly. Spire concealed. Posterior edge of outer lip rising slightly above apex. Parietal wall covered with thick, smooth white callus. Spiral sculpture composed of punctuated striations. Punctations rectangular, in rows of variable sizes. Thick, pale orange to brownish periostracum. Shell dirty white to pale yellow.

Radula ( Fig. 23A–C View Figure 23 ): Radular formula 21 × 1.1.1 (H = 28 mm). Lateral teeth curved, with weak denticulation on inner edge. Rachidian teeth sub-rectangular, elongate, with cusps slightly curved inwards.

Digestive tract ( Fig. 23D, E View Figure 23 ): Salivary glands long, thin, surface uneven. Paired gizzard plates sub-triangular to kidney-shaped.

Male reproductive system ( Fig. 23F, G View Figure 23 ): Penial chamber cylindrical, lined with soft longitudinal ridges towards genital opening, bulged around prostatic duct entrance, lined with warts and wrinkles. Muscular papilla absent. Penial chamber separated from prostate by short prostatic duct. Prostate cylindrical, rounded at end.

Ecology: Found between 964 and 1793 m depth (Lörz et al. 2012; present study). Feeds on foraminifera (present study).

Distribution ( Fig. 8 View Figure 8 ): Eastern New Zealand ( Dell 1956, Morley and Hayward 2009, Rowden et al. 2016; present study).

Remarks: The shell of S. otagoensis is similar to those of S. interruptus and S. amygdalus , especially in their juvenile forms. The three species occur around New Zealand, with their bathymetric ranges overlapping. However, S. otagoensis has a more pronounced pyramidal shell, with straighter lateral edges, a posterior part more acute, and a notable darker periostracum. The overall shape of the shell of S. interruptus is similar but with lateral and posterior edges slightly more rounded, and the S-curve of its parietal wall and aperture is more pronounced. The shell of S. amygdalus is more oval than S. otagoensis , with a noticeable narrowing of the posterior edge of the shell, giving it an almond shape. Scaphander interruptus differs anatomically by lacking warts lining the deeper part of the penial chamber, but S. otagoensis and S. amygdalus have similar internal features, which makes distinction based on anatomical characters challenging (see S. amygdalus and S. interruptus sections). These sister species are distinct genetically, with uncorrected p -distances for COI estimated at 9.01%–10.03% between S. otagoensis and S. interruptus , 10.14%–11.76% between S. interruptus and S. amygdalus , and 11.91%–13.39% between S. otagoensis and S. amygdalus .