Tongsuapusia tehuaorum Huang, 2015: 46

Tongsuapusia tehuaorum Huang, 2015: 46 View in CoL ; pl. 1, fig. 7.

Type data

Holotype: NMNS 7523-001, South China Sea, Pratas Islands, 600 m, 28.24 9 10.05 mm.

Material examined

Taiwan: South China Sea , Expedition NANHAI, station CP4100, 15 ° 05 0 N, 116 ° 32 0 E, 534 – 552 m, 2 lv (MNHN IM-2013-44099, 20.7 mm, Fig. 12G; MNHN IM-2013-44103, lv, 19.0 mm); station CP4102, 15 ° 03 0 N, 116 ° 31 0 E, 339 – 533 m, 3 lv (MNHN IM-2013-44146, 18.0 mm, Fig. 12H, I; MNHN IM-2013- 44156, 18.85 mm, and MNHN IM-2013-44158, 19.4 mm); station CP4103, 15 ° 05 0 N, 116 ° 30 0 E, 633 m, 2 lv (MNHN IM-2013-44191, 15.85 mm, and MNHN IM-2013-44200, 16.6 mm) GoogleMaps .

Papua New Guinea: PAPUA NIUGINI, station DW3983, 05 ° 12 0 S, 146 ° 59 0 E, 470 – 508 m, Bismarck Sea , North-West of Long Island, 1 lv (MNHN IM-2013-19796, 22.7 mm, Fig. 12K) GoogleMaps .

New Caledonia: TERRASSES, station DW3036, 22 ° 41 0 S, 168 ° 58 0 E, 800 m, Loyalty ridge, 1 lv (MNHN IM-2013-40663, 15.5 mm, Fig. 12L); Norfolk 2, station DW2081, 25 ° 54 0 S, 168 ° 22 0 E, 500 – 505 m, Norfolk ridge, 1 lv (23.7 mm, Fig. 12M); station DW2087, 24 ° 56 0 S, 168 ° 22 0 E, 518 – 586 m, Norfolk ridge, 1 lv (25.9 mm) GoogleMaps .

Society Islands: TARASOC, station CP3458, 16 ° 46 0 S, 151 ° 23 0 W, 573 – 611 m, Raiatea, 1 lv (MNHN IM-2007-39258, Fig. 12N).

Diagnosis

Shell fusiform to elongate fusiform with high, typically acuminate spire and wide last adult whorl. Protoconch cyrtoconoid, brown, with 4.5 convex glossy whorls. Early spire whorls distinctly shouldered, rarely flattened, subsequent teleoconch whorls with convex outline. Sculpture of strong orthocline axial ribs intersected by a single adapical spiral cord, which is faint between axials and forms distinct beads at intersections. Last adult whorl evenly convex; siphonal canal moderately long, tapering, widely open. Aperture elongate, outer lip thin, notably drawn towards tip of siphonal canal, lacking lirae. Inner lip with four columellar folds, the adapicalmost strongest, and subsequent folds gradually diminishing. Background colour teleoconch with white apex and indistinct tan spiral bands on late teleoconch whorls.

Anatomy (MNHN IM-2013-44099)

External morphology: Body pale, lacking pigmentation, with massive head-foot, operculum absent. Siphon simple, rather long. Head with a pair of long eye tentacles ( Fig. 13C, D View Figure 13 ). Eyes large, situated laterally at base of tentacles. Mantle thin, transparent; mantle cavity spanning over two-thirds of last whorl. Ctenidium moderately long, occupying about half the length of mantle cavity, osphradium large, only slightly smaller than ctenidium. No distinct anal gland present.

Anterior alimentary canal: Proboscis conical, in contracted state rather short, occupying about half of the rhynchocoel length. Rhynchodaeum thin, with two retractors attached ventrally to its anterior part ( Fig. 13E View Figure 13 ). Buccal mass situated at mid-length of proboscis, with distal part of radular sac reaching proboscis base. Buccal mass enclosing thin horseshoe-shaped jaw, connected to odontophore by very feeble fibres of connective tissue. Anterior oesophagus forming a loop that lies dorsally above large bulky salivary glands and terminates at distinct pyriform valve of Leiblein. Very thin salivary ducts adjoining mid-oesophagus for a short distance before the valve of Leiblein. Acessory salivary gland bulbous, translucent, situated laterally, partly embedded into salivary gland. Mid- oesophagus situated right behind the circum-oesophageal nerve ring, forming a very short widened glandular compartment. Posterior oesophagus thin, covered dorsally by very long, brown, bulky, gland of Leiblein.

Radula (of holotype; Fig. 13F View Figure 13 ): Radula about 0.4 mm long and 0.1 mm wide, consisting of about 54 rows. Rachidians tricuspidate with moderately wide base attaining about 37% of radula width. Three cusps of rachidian of about equal length, strong, pointed. Lateral cusps directed slightly sideways. Anterior margin of rachidian forming sharp blade-like edge. Laterals sickle-shaped, unicuspidate.

Male reproductive system: The specimen is a male, with a large, flattened, folded penis with no distinct papilla ( Fig. 13D View Figure 13 ). Seminal groove open, spanning the entire length of the penis along its inner edge.

Distribution and habitat

South China Sea, Papua New Guinea, New Caledonia (Loyalty and Norfolk ridges), French Polynesia, hard bottoms, depth range 505 – 800 m.

Remarks

Alisimitra tehuaorum was described based on a single dead collected shell lacking the protoconch ( Huang, 2015: pl. 1, fig. 7a – c), which exceeds in size the specimens studied herein; however, we are confident about the identity of this species. In general, specimens of Alisimitra tehuaorum from different localities show significant variation in shell shape, whorl outline, and number of axial ribs. The form from the South China Sea ( Fig. 12G – I) has convex whorls that are somewhat shouldered in appearance because of the distinct beads at the intersection of spiral and axial sculpture. By contrast, specimen MNHN IM-2013-19676 from Papua New Guinea ( Fig. 12K) has flattened late spire whorls and weaker spiral sculpture. All specimens of Alisimitra tehuaorum , from the South Pacific [including MNHN IM-2013-19676 from Papua New Guinea, MNHN IM-2013-40663 from New Caledonia ( Fig. 12L), and MNHN IM-2007-39258 ( Fig. 12N) from the Society Islands] have notably finer and denser axial ribs, numbering 23 – 25 on last adult whorl. The conspecificity of the South China Sea and South Pacific populations is confirmed by molecular data, however.

Alisimitra tehuaorum is most similar to Alisimitra barazeri sp. nov. (see above), but Alisimitra tehuaorum has a more fusiform shell outline whereas Alisimitra barazeri sp. nov. is more turriform, with a strongly convex base. Besides, specimens of Alisimitra tehuaorum and Alisimitra barazeri sp. nov. from the South Pacific can be distinguished by the axial sculpture: finer and denser ribs in Alisimitra tehuaorum ; stronger and more widely spaced in Alisimitra barazeri sp. nov. The lack of spiral grooves segregates Alisimitra tehuaorum from Alisimitra deforgesi sp. nov. and Alisimitra fuscolineata , with the latter two remarkable for contrasting spiral bands or lines, which are lacking in Alisimitra tehuaorum . Finally, the denser axial ribs and comparatively much wider last adult whorl immediately distinguish Alisimitra tehuaorum from Alisimitra samadiae sp. nov.

ALISIMITRA SAMADIAE SP. NOV. FEDOSOV, HERRMANN & BOUCHET

FIGURE 14A – C View Figure 14

Type data

Holotype: MNHN IM-2013-40638, PAPUA NIUGINI, station CP4079, 04 ° 34 0 S, 145 ° 52 0 E, 960 m, Papua New Guinea, Bismarck Sea , West of Karkar Island, lv, 20.3 mm ( Fig. 14A, B View Figure 14 ). GoogleMaps

Other material examined

New Caledonia: EXBODI, station CP3842, 22 ° 23 0 S, 167 ° 22 0 E, 756 – 769 m, off Passe de la Sarcelle, 1 dd (14.75 mm; Fig. 14C View Figure 14 ) GoogleMaps .

Diagnosis

Shell elongate, with strong axial sculpture and very high orthoconoid spire. Protoconch cyrtoconoid, brown, with about four convex, glossy whorls. Early teleoconch whorls shouldered, later whorls flattened. Sculpture of very strong and widely spaced axial ribs overridden by a single spiral cord, situated slightly above whorls mid-height, more pronounced on earlier whorls, very faint in interspaces between ribs. Siphonal canal moderately long, tapering, slightly recurved. Aperture narrow, outer lip very thin, smooth inside. Inner lip with three strong columellar folds, adapicalmost strongest. Shell off-white.

Description

Shell elongate – turriform, with high spire and rather low aperture (w / h 0.28; a / h 0.4 – 0.42). Protoconch cyrtoconoid, brown, with about four convex, glossy whorls. Teleoconch of about 7.5 adpressed whorls; suture deeply impressed, canaliculate. Axial sculpture of very strong, straight, widely spaced ribs (12 on penultimate whorl) and fine growth lines. Last adult whorl with 13 ribs, of which the last few are wider and weaker, sculpture behind outer lip represented essentially by distinct growth lines. Spiral sculpture of a single spiral cord, situated at adapical third of whorl height, forming rounded beads at intersection with axial ribs, rather feeble in interspaces between them. Rounded beads on axial ribs well pronounced on early teleoconch whorls, vanishing on penultimate and last adult whorls. Shell base smooth, convex, with gradual transition to rather short, slightly recurved siphonal canal, sculptured only by growth lines. Aperture elongate, evenly convex, reaching tip of siphonal canal. Outer lip thin, smooth inside. Inner lip slightly bent abaxially, with three strong, subequal columellar folds. Shell off-white.

Radula (of holotype; Fig. 13G View Figure 13 ): Radula about 0.6 mm long and 0.12 mm wide, consisting of 55 rows. Rachidians tricuspidate, with rather wide, bow-shaped base, its anterior margin forming distinct blade-like edges laterally; three rachidian cusps rather long and pointed, very closely set, lateral cusps directed notably sideways. Laterals unicuspidate, sickle-shaped, bearing irregular plicae at base of cusp.

Distribution and habitat

Papua New Guinea (Bismarck Sea), New Caledonia, depth range 769 – 960 m.

Etymology

The species is named in honour of Sarah Samadi, the cruise leader of the deep-water expeditions to Papua New Guinea, including the PAPUA NIUGINI cruise of 2012 during which the holotype was collected .

Remarks

The specimen of Alisimitra samadiae sp. nov. from New Caledonia retains a protoconch with the same morphology as protoconchs in other Alisimitra species. Alisimitra samadiae sp. nov. differs markedly from other Alisimitra species by its, by far, more elongate shell, with very strong axial sculpture and rather smooth siphonal canal. In shell proportions and morphology of the suture, it rather resembles some species of Tosapusia , but can be readily distinguished from them by its adpressed whorls and lack of spiral sculpture other than the single spiral cord, and by the protoconch morphology, which is shared with other Alisimitra species.