Lucinoma vestita ( Dautzenberg & Fischer, 1906 )

Cosel, Rudo von, 2006, Taxonomy of tropical West African bivalves. VI. Remarks on Lucinidae (Mollusca, Bivalvia), with description of six new genera and eight new species, Zoosystema 28 (4), pp. 805-851 : 828-830

Lucinoma vestita ( Dautzenberg & Fischer, 1906)

( Figs 14 ; 15A, B )

Phacoides (Lucinoma) vestita Dautzenberg & Fischer, 1906: 90-91 , pl. 5, figs 1-5.

TYPE MATERIAL. — Figured syntype: Cap Verde Islands , near Maio, 15°14’N, 23°04.1’W, 628 m, muddy sand, trawled RV Princess Alice, 14.VIII.1901, 1 complete sh. ( MOM) ; same locality, 3 other syntypes: 2 sh., 1 worn rv. (all MOM) .

TYPE LOCALITY. — Maio, Cape Verde Islands.

DISTRIBUTION. — Only known from the Cape Verde Islands.

DESCRIPTION

Shell 12-16 mm long, thick and solid, subcircular, inequilateral, equivalve, compressed.Beaks slightly in front of the vertical midline.Anterior margin rounded, posterior margin obliquely rounded-truncated with rounded corners. Postero-dorsal margin slightly convex. Ventral margin evenly semicircular.

Exterior with numerous, very fine, irregular growth lines, occasionally more or less eroded on the umbonal part of the valves; commarginal lamellae only visible in the region of the posterior angle if at all. Earlier part of the valves appearing smooth. Posterior area delimited by gently rounded posterior angle, anterior angle absent.

Hinge plate very broad, especially under the umbones, with a rather thin anterior and a strong posterior cardinal tooth in the right valve and a strong, slightly bifid anterior and a thinner and more laminar posterior cardinal in the left valve. Anterior laterals in both valves small and knob-like but well defined, posterior laterals ill-defined or obsolete. Lunule quite broad with thick layer of periostracum. Escutcheon long and narrow, ligament deeply inset. Anterior adductor scar rather small, its diverging part very long and narrow. Inner margin of valves smooth.

Valves entirely white. Periostracum yellowish brown, on the earliest parts of the valve thin to obsolete (eroded).

Measurements are provided in Table 6.

BIOTOPE

Muddy-sandy bottom on the shelf slope at about 600 m.

REMARKS

This species is the smallest West African Lucinoma , it is distinguished from the other Lucinoma of the region by the very broad hinge plate under the umbones, which, together with the concave lunular area, gives the beaks a more raised appearance.

Figures

FIG. 14. — Lucinoma vestita (Dautzenberg & Fischer,1906): A, figured syntype, near Maio, Cap Verde Islands,15°14’N,23°04.1’W, 628 m, muddy sand, trawled RV Princess Alice, 14.VIII.1901, 15.8 mm (MOM), exterior of both v., dorsal view; B, syntype 2, same locality, 14.7 mm (MOM), exterior and interior of both v.; C, syntype 3, same locality, 12.9 mm (MOM), interior and exterior of rv.

FIG. 15. — Half schematic drawings of the insides of right valves: A, B, Lucinoma vestita (Dautzenberg & Fischer, 1906); A, figured syntype; B, syntype 2; C, D, Lucinoma atalantae n. sp.; C, holotype; D, paratype 1. Scale bars: 10 mm.