Scaphander subglobosa Schepman, 1913

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 678-681

Scaphander subglobosa Schepman, 1913

Figs 43, 44C-G, 45D-F

Scaphander subglobosa Schepman, 1913: 466-467 , pl. 32, fig. 1.

TYPE MATERIAL. — 1 syntype ZMA 3.13 .117 .

FIG. 44. Shell morphology of species of Scaphander Montfort, 1810 . A, Scaphander sibogae Schepman, 1913 , (24 mm), ventral view, Indonesia, CORINDON stn CH 280; B, same shell, posterior view. C, Scaphander subglobosa Schepman, 1913 , large shell, (35 mm), ventral view, Indonesia, KARUBAR stn CP 20; D, same shell,posterior view; E, (28 mm), ventral view of the posterior end, Indonesia,KARUBAR stn CP 72; F, (29 mm),ventral view of the posterior end, Indonesia, KARUBAR stn CC 56; G, (28 mm), ventral view of the posterior end, Philippines,MUSORSTOM 2 stn CP 25.

FIG. 45. Shell sculpture, gizzard plates and radula of species of Scaphander Montfort, 1810 . A-C, Scaphander sibogae Schepman, 1913 . A, sculpture, Indonesia, KARUBAR stn CP 73, scale bar = 300 Μm; B, radula, Indonesia, CORINDON stn CH 280, scale bar = 200 Μm; C, same specimen, gizzard plates, scale bar = 2 mm. D-F, Scaphander subglobosa Schepman, 1913 . D, sculpture, Philippines, MUSORSTOM 2 stn CP 25, scale bar = 1 mm; E, radula, Indonesia, KARUBAR stn CC 21, scale bar = 100 Μm; F, same specimen, gizzard plates, scale bar = 2 mm.

TYPE LOCALITY. — Indonesia, 02°40’S, 128°37.5’E, 835 m [ Siboga : stn 178] .

MATERIAL EXAMINED. — Philippines. MUSORSTOM 2: stn CC 21 , 05°14’S, 133°00’E, 688-694 m, 1 lv ( Figs 45E, F); stn CP 25, 13°39’N, 120°43’E, 520-550 m, 9 dd ( Figs 44G, 45D); CP 38, Tanimbar Islands, 07°40’S, 132°27’E, 620-666 m, 1 stn CP 36, 13°31’N, 121°24’E, 569-595 m, 9 dd; stn CP 44, dd; stn CP 54, 08°21’S, 131°43’E, 836-869 m, 2 dd; stn DW 13°23’N, 122°20’E, 760-820 m, 2 dd; stn CP 82, 13°47’N, 28, 05°31’S, Kai Islands, 132°54’E, 448-467 m, 1 dd; stn CC 120°29’E, 550 m, 1 dd . — MUSORSTOM 3: stn CP 122, 12°20’N, 56, 08°16’S, 131°59’E, 552- 549 m, 9 dd ( Fig. 44F); stn CC 121°42’E, 673-675 m, 14 dd. 57, 08°19’S, 131°53’E, 603-620 m, 1 dd; stn CP 72, 08°36’S, Indonesia. The type material . — KARUBAR: stn CP 20, Kay Is- 131°33’E, 676-699 m, 9 dd (Fig. 44E) .

lands, 05°15’S, 132°59’E, 769-809 m, 1 dd (Figs 44C, D); stn

DISTRIBUTION. — Originally described from Indonesia, in 835 m (Schepman 1913). Material herein collected in Indonesia and the Philippines (Fig. 43), in 467-836 m, live in 688-694 m.

DESCRIPTION. — Shell morphology. Length 36 mm, width 25 mm (largest specimen examined). Shell solid, oval, with convex sides (Fig. 44C). Location of the widest region of the shell varies among specimens. In larger shells (c. 25 mm or longer) it is near the anterior end (Figs 44C), whereas in smaller shells (c. 25 mm or shorter) it is near the centre. Only 1 whorl visible, forming nearly the entire shell. Apex variable, rounded in some specimens (Fig. 44G), more elongate in others (Figs 44E, F), slightly depressed, not umbilicate (Fig. 44D), with the aperture lip rising from the left side, forming a short wing. The wing is larger in some specimens (Fig. 44F) than in others (Figs 44E, G). Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing abruptly near the middle of the shell. Columellar margin thickened, with no callus. Sculpture of a number of punctuated spiral grooves (Fig. 45D). The punctuations are large, oval, and situated next to each other within each groove. The grooves are separated by gaps narrower than the grooves near the inner whorls and wider than the grooves near the outer edge of the shell. Occasionally narrower grooves are intercalated. Colour uniform brownish except for the shells that have lost the periostracum and are snowy white.

Anatomy. The digestive system contains 3 smooth gizzard plates, of which 2 are large and oval, whereas the third is elongate (Fig. 45F). The radular formula is 15 x 1.0. 1 in a specimen from Indonesia (KARUBAR stn CC 21). The lateral teeth are elongate and hook-shaped, with a very short base and a sharp, long, curved cusp (Fig. 45E).

REMARKS. — Scaphander subglobosa was described based on 2 shells collected in Indonesia in 794-835 m (Schepman 1913), one of them a juvenile specimen doubtfully assigned to the species. Schepman (1913) indicated that S. subglobosa differs from S. sibogae and S. attenuatus in several details of the shell morphology. Examination of the remaining syntype of S. subglobosa revealed that some of the specimens newly collected from Indonesia and the Philippines agree with the characteristics of this species, which is consistently different from S. sibogae in shell morphology. The shells of S. subglobosa are wider and less oval, with proportionately larger spiral grooves. Anatomically, the radular teeth of S. subglobosa are more curved and have a shorter cusp, and the central gizzard plate is much wider and shorter.

Scaphander illecebrosus Iredale, 1925 , originally described from Australia (Iredale 1925), is similar to S. subglobosa , but is kept as a separate species until complete specimens become available for study.