Episiphon indefensum, Scarabino & Scarabino, 2010

Scarabino, Victor & Scarabino, Fabrizio, 2010, A new genus and thirteen new species of Scaphopoda (Mollusca) from the tropical Pacific Ocean, Zoosystema 32 (3), pp. 409-423 : 416

Episiphon indefensum n. sp.

( Fig. 3 E-G)

TYPE MATERIAL. — Solomon Islands. SALOMON 2, stn CP 2182, 08°47’S, 159°38’E, 762-1060 m, 1 dd holotype ( MNHN 22786 ) ; 2 dd paratypes ( MNHN 22787 ) .

TYPE LOCALITY. — Solomon Islands, 08°47’S, 159°38’E, 762-1060 m (SALOMON 2, stn CP 2182).

ETYMOLOGY. — From the Latin indefensus (meaning undefended, unprotected) refering to the multiple fractures observed in all specimens studied.

OTHER MATERIAL EXAMINED. — Solomon Islands. SALOMON 2, stn CP 2182, 08°47’S, 159°38’E, 762- 1060 m, 19 dd.

DISTRIBUTION. — Only known from the type locality. Shells at 762-1060 m.

DESCRIPTION

Shell 7.9 mm long, well curved with the arc located at posterior ⅓ of shell, slowly tapering, opaque cream. Longitudinally sculptured with 48 fine striae and secondary ones that appear at the posterior ¼ of the shell. Apex simple circular, callus thin, lumen central, circular, large. Anterior aperture straight, circular.

Measurements of holotype:L 7.9, W 0.63, w 0.32, arc 0.72 at 3.6 from apex.

REMARKS

Breakages and repairs of unknown origin are present in all specimens studied. Compared to E. joanae n. sp. and E. wallisi n. sp., the present new species has an intermediate number of striae, its arc is located posterior, the lumen is much larger due to its thin apical callus. Episiphon truncatum ( Boissevain, 1906) (syntypes ZMA 3.06.065-067, examined) from Indonesia (281 m), has almost similar breakages as E. indefensum n. sp. in adult specimens, but is much larger, solid, brilliant, the sculpture consists of encircling wrinkles in the apical sector and the apical section is roughly subtriangular. The apical callus of E. indefensum n. sp. is clearly thin for the genus.

Figures

FIG. 3. — A-D, Episiphon wallisi n. sp. holotype (6.5 mm), Wallis Island, 13°21’S, 176°08’W, 415-420 m (MUSORSTOM 7 stn DW 604);A, lateral view of shell; B, dorsal view of shell; C, frontal view of apex; D, sculpture at the posterior third of shell; E-G, Episiphon indefensum n. sp. holotype (7.9 mm), Solomon Islands, 8°47’S, 157°38’E, 762-1060 m (SALOMON 2 stn CP 2182); E, lateral view of shell; F, dorso-frontal view of apical area; G, sculpture at the middle of shell; H, I, Episiphon joanae n. sp. holotype (7 mm), Fiji, Ride de Lau, 18°43’S, 178°23’W, 392-407 m (BORDAU 1 stn DW 1469); H, lateral view of shell; I, latero-dorsal view of apical area; J, Episiphon joanae n. sp., radula, rachidian and lateral teeth; K, L, Episiphon lacteum n. sp. holotype (16 mm), Waterwitch Bank, Wallis Island, 12°31’S, 176°40’W, 275-295 m (MUSORSTOM 7 stn DW 538); K, lateral-dorsal view of apical area; L, lateral view of shell. Scale bars: F, G, I, K, 100 μm; J, 10 μm.