Tongsuapusia duplex, Huang, 2015

Tongsuapusia duplex, Huang, 2015 View in CoL : pl. 1, fig. 2.

Type data

Holotype: Papua New Guinea, Bismarck Sea , off Bagabag Island, PAPUA NIUGINI, station CP3979, 04 ° 44 0 S, 146 ° 11 0 E, 540 – 580 m, lv (MNHN IM-2013- 19695, 35.1 mm; Fig. 6D, E View Figure 6 ). GoogleMaps

Paratypes: PAPUA NIUGINI, station CP4008, 06 ° 04 0 S, 148 ° 10 0 E, 500 – 555 m, lv (paratype 1, MNHN IM-2013-19915, 35.2 mm) GoogleMaps ; Papua New Guinea, South-East point of Manus Island , BIOPAPUA, station CP3672, 04 ° 04 0 S, 151 ° 50 0 E, 702 – 724 m, lv (paratype 2, MNHN IM-2000-30201, 25.9 mm) GoogleMaps ; Papua New Guinea, North of Rabaul , BIOPAPUA, station CP3691, 02 ° 11 0 S, 147 ° 18 0 E, 499 – 517 m, lv (paratype 3, MNHN IM-2000-30202, 25.9 mm; Fig. 6F View Figure 6 ) GoogleMaps .

Other material examined

Solomon Islands: Guadalcanal, Salomonboa – 3, station CP2772, 09 ° 25 0 S, 160 ° 31 0 E, 456 – 551 m, 1 (MNHN IM-2007-36135, 23.2 mm); Salomon – 2, station CP2194, 08 ° 25 0 S, 159 ° 27 0 E, 440 – 521 m, 1 (29.9 mm) GoogleMaps .

Diagnosis

Shell thin walled, medium sized, elongate fusiform, with high spire and long tapering siphonal canal. Early teleoconch whorls cylindrical, later whorls slightly convex with whorl periphery shifted abapically, having slightly compressed outline. Axial sculpture of numerous, distinctly opisthocline, fine axial ribs. Spiral sculpture of regular fine grooves, better seen in interspaces between axials, second uppermost groove widened, overriding axial elements. Siphonal canal straight, long, tapering, aperture elongate, opening of siphonal canal very wide and shallow. Inner aperture lip with three widely interspaced columellar folds, with the adapicalmost fold being strongest. Protoconch light brown, with two or more smooth whorls. Shell whitish, retaining pale background colour in interspaces between axial ribs on late spire whorls.

Description

Shell medium sized, fusiform (w / h 0.26; a / h 0.45 – 0.46), with high slender spire and elongate aperture. Protoconch light brown, with two or more smooth glossy whorls with clear-cut protoconch/teleoconch transition. Teleoconch of ten and one-quarter whorls, suture distinct, impressed. Early spire whorls cylindrical, with very distinct subsutural shelf, strongly angulated. Later teleoconch whorls with slightly convex outline and less notable subsutural shelf. Axial sculpture of strong but rather narrow and closely set axial ribs, with rather deep intervals, 25 on last adult whorl. Axials distinctly opisthocline on spire whorls and only slightly prosocline on last adult whorl, intersected by a deep groove just below the suture, their adapical portions forming indistinct ‘caps’ well pronounced on early spire whorls. Adapical area of last adult whorl with two grooves, caps rather indistinct. Below adapical groove spiral sculpture represented by fine, stroke-like, grooves in interspaces between strong axial ribs, seven or eight on penultimate whorl, 15 on last adult whorl, giving way towards siphonal canal to low, rounded, spiral cords, more oblique at the tip of canal. Siphonal canal long and straight. Aperture elongate (AL/SL), narrow, not clearly delineated from siphonal canal. Outer apertural lip gently convex at its adapical part and nearly straight below; inside of outer lip without lirae. Four columellar folds, adapical one strongest, and with succeeding folds gradually reducing in size, with third one rather weak and fourth one indistinct. Shell whitish, retaining pale background colour in interspaces between axial ribs on late spire whorls.

Radula (of holotype; Fig. 7F View Figure 7 ): Radula ~ 1 mm long and 0.23 mm wide, with more than 45 rows. Tricuspidate rachidian with relatively wide base (about one-third of radular width) and short blunt cusps of equal size, set on robust medial projection. Laterals unicuspidate, triangular to widely sickle-shaped, with drawn cusp, sometimes bearing irregular minor cusps on inner edge.

Distribution and habitat

Papua New Guinea (Bismarck Sea and Solomon Sea), Solomon Islands, East China Sea ( Huang, 2015), alive in depths of 517 – 702 m.

Etymology

The species name refers to the Bismarck Sea as the type locality.

Remarks

In shell morphology, Tosapusia bismarckeana sp. nov. most resembles Tosapusia duplex ; however, it can be distinguished from it by being narrower, with more numerous axial ribs, which are distinctly opisthocline (about orthocline in Tosapusia duplex ). Overall the axial sculpture of numerous rounded opisthocline ribs differentiates Tosapusia bismarckeana sp. nov. from other species of Tosapusia .

TOSAPUSIA KURODAI ( SAKURAI & HABE, 1964) View in CoL