Wallucina Iredale, 1930

Glover, Emily A. & Taylor, John D., 2007, Diversity of chemosymbiotic bivalves on coral reefs: Lucinidae (Mollusca, Bivalvia) of New Caledonia and Lifou, Zoosystema 29 (1), pp. 109-181 : 161-162

Genus Wallucina Iredale, 1930

Wallucina Iredale, 1930: 390 . Type species: Lucina jacksoniensis Smith, 1885 (prior valid name Wallucina assimilis (Angas, 1867)) (original designation).

DIAGNOSIS. — Shells small, subcircular in outline. Moderately inflated, relatively thin-shelled. Sculpture of fine, closely spaced commarginal lamellae, sometimes slightly raised to posterior, fine radial stri ations sometimes present. Hinge plate narrow. RV with single cardinal tooth and posterior lateral tooth, anterior lateral absent or very small. LV with two cardinal teeth and a posterior lateral tooth. Ligament internal, set in elongate,oblique resilifer.Anterior adductor muscle scar elongate, detached from pallial line for about 1/2 to 1/3 of length. Pallial line irregularly lobed and divided. Inner shell margin finely crenulate.

Wallucina fijiensis ( Smith, 1885) ( Figs 34A ; 35 )

Lucina (Codakia) fijiensis Smith, 1885: 184 , pl. 13, fig. 9.

Lucina (? Loripes ) gordoni Smith, 1885: 186 , pl. 13, fig. 12.

Loripes haddoni Melvill & Standen, 1899: 200 , fig. 12.

Wallucina gordoni – Maes 1967: 159, pl. 22, fig. e.

Wallucina fijiensis – Glover & Taylor 2001: 289, fig. 24a, b.

TYPE MATERIAL. — L. fijiensis: Levuka , Fiji, holotype ( BMNH 1887.2.9).

L. gordoni: Levuka , Fiji, holotype ( BMNH 1887.2.9. 2886).

L.haddoni: Torres Strait,Warrior Island, holotype (BMNH 1899.2.23.12).

TYPE LOCALITY. — L. fijiensis: Levuka , Fiji

MATERIAL EXAMINED. — Koumac. 1 stn, 11-13 m, 2 v.

Touho. 5 stn, 0-6 m, 328 v, 1 live.

Lifou. 7 stn, 1-12 m, 39 v, 4 live.

Other New Caledonia. LAGON, stn 49, secteur de Nouméa, 22°19’S, 166°14’E, 10 m, 1 v. — Stn 284, 22°26’S, 166°25’E, 6 m, 1 v. — Stn 1510, Quatres Bancs de l’Ouest, 22°27’S, 166°68’E, 1 m, 30 v.

DISTRIBUTION. — Eastern Indian Ocean to West Pacific: Cocos Keeling Atoll, Great Barrier Reef, to Southern Japan, Guam, Kiribati, Fiji (see Glover & Taylor 2001).

DESCRIPTION

Shell white, small, thin, H to 15 mm, circular to subcircular in outline; posterior shell margin slightly truncate. Protoconch 160 µm long, PI smooth, 110 µm, PII with growth increments. Sculpture of extremely fine, low commarginal lamellae with fine radial striae between commarginal lamellae ( Fig. 35E ).Commarginal lamellae are slightly broader and more elevated near dorsal margins. Lunule narrow, lanceolate to heart-shaped and slightly excavated. Anterior dorsal area often with irregular folds. Hinge plate narrow; RV with prominent cardinal tooth, two small posterior lateral teeth and tiny anterior lateral tooth. LV with two cardinals, anterior cardinal is trigonal and larger, posterior laterals are low and anterior lateral absent. Ligament internal, deeply impressed into each valve. Anterior adductor muscle scar short, broad and detached from the pallial line for about 1/2 of length. Pallial line with irregular lobes and partially divided.Pallial blood vessel impression faint. Surface of shell inside pallial line with indistinct, narrow, radial ridges, shell outside the pallial line glossy with fine radial striations. Shell margin finely denticulate.

Figures

FIG. 34. — Outline drawings of interiors of right valves of Pillucina Pilsbry, 1921, Wallucina Iredale, 1930, Chavania Glover & Taylor, 2001 and Funafutia Glover & Taylor, 2001 species: A, W. fijiensis (Smith, 1885); B, C. striata (Tokunaga, 1906); C, P. pacifica Glover & Taylor, 2001; D, P. copiosa n. sp.; E, F. levukana (Smith, 1885). Not to scale.

FIG. 35. — Wallucina fijiensis (Smith, 1885):A, B, exterior and interior of right valve,Touho,stn 1242, New Caledonia; C, D, exterior and interior of right valve, Touho, stn 1242; E, detail of surface sculpture; F, umbonal area, Lifou, stn 1420; G, interior of left valve juvenile shell, Lifou, stn 1240; H, protoconch, Lifou, stn 1240; I, J, details of hinge teeth of left and right valves of A. Scale bars: A-D, 2 mm; E, 200 µm; F, G, I, J, 1.0 mm; H, 75 µm.