(Figs 3E; 4)
TYPE MATERIAL. — Holotype: 1 sh, L 6.0 mm, H 5.3 mm, T 2.3 mm (MNHN).
Paratypes: New Caledonia, Passe de Touho, 20°49’S, 166°19’E, 80-140 m, stn 1249, muddy sand to mud, 290 v (MNHN); 10 v (BMNH 20050568). — Figured paratypes:same locality, L 4.3 mm, H 3.7 mm; L 4.3 mm, H 3.8 mm; L 4.1 mm, H 3.7 mm; L 4.4 mm, H 3.8 mm (MNHN).
TYPE LOCALITY. — New Caledonia, secteur de Yaté, stn 622, 22°02’S, 166°53’E, 67 m.
ETYMOLOGY. — Greek diaphanes, transparent.
MATERIAL EXAMINED. — Koumac. 2 stn, 30-120 m, 56 v.
Touho. 3 stn, 50-140 m, 217 v.
Other New Caledonia. LAGON, stn 429, Grand Récif Sud, 22°40’S, 167°15’E, 95 m, 1 v. — Stn 830, secteur de Poindimie, 20°49’S, 165°19’E, 105-110 m, 10 v.
BATHUS 1, côte est, stn DW 674, 20°49’S, 165°19E, 105-110 m, 50 v. — Stn DE 700, 20°57’S, 165°35’E, 160-222 m, 5 v.
MUSORSTOM 4, stn DW 150, 19°07’S, 163°22’E, 110 m, 3 v.
Loyalty Islands. Stn DW 1650, 20°54’S, 167°02’E, 120-250 m, 11 v.
DESCRIPTION
Shell small, H to 5.3 mm, L to 6.0 mm, relatively inflated, very thin-shelled, translucent to white. Shell ovoid,longer than high,anterior attenuated,posterior shell margin often truncated. Umbones low, central. Protoconch large glassy, 150 µm, PI well marked (65 µm), smooth, PII with regular growth increments. Sculpture of regularly spaced, thin, commarginal lamellae.Faint radial anterior and posterior sulci.Hinge narrow, normal hinge teeth absent. Small knob lies below the umbones of both valves contiguous with thin flange on the anterior part of the hinge (Fig. 4G, H). Ligament narrow,short,set in shallow groove.Anterior adductor muscle scar short,reniform in outline,slightly detached from the pallial line.Pallial line entire.Shell margin with thin peripheral groove.
REMARKS
Leucosphaera diaphana n. sp. is similar to the type species, L. salamensis, from the western Indian Ocean but has a more elongate, anteriorly extended shell, a truncate posterior margin and more closely spaced commarginal lamellae.