Notocina falklandica (Dell, 1964)

Taylor, John D. & Glover, Emily A., 2019, Unloved, paraphyletic or misplaced: new genera and species of small to minute lucinid bivalves and their relationships (Bivalvia, Lucinidae), ZooKeys 899, pp. 109-140 : 109

Notocina falklandica (Dell, 1964) Fig. 13

Epicodakia falklandica Dell, 1964: 206, fig. 4 (17, 18, 19).

Type material.

Holotype: NHMUK 1962857/1; Paratypes: NHMUK 1962858/1; 1962859/1; 1962860/1; 1962861/2; 1962862/2.

Type locality.

Off Falkland Islands, Discovery station WS 766. 44°58'S, 60°05'30"W, 545 m. Paratype depth range 105-219 m.

Material examined.

South Georgia, 53.561108S, 37.88494W, 221 m BIOPEARL cruise 1, 05.04.2006 sample B-06-1167. GenBank numbers: 18S KF741615, 28S KF741644, cyt b KF741675.

Description.

Shells small, L 2-3 mm, ovoid, slightly longer than high. Umbones prominent. Posterior dorsal margin straight. Sculpture of low rounded commarginal lamellae with narrow interspaces. Faint radial ribs visible to anterior and posterior. Microsculpture of dense fine punctae (2-3 µm in diameter). Protoconch: P1 = 188 µm, P1 + P2 = 242 µm, P2 with fine growth increments (South Georgia shell). Ligament short, protruding above posterior dorsal margin ( Fig. 13J ), set in shallow nymph. Escutcheon well defined, smooth. Lunule slightly impressed, broadly lanceolate. Hinge line narrow, left valve with two small cardinal teeth and anterior and posterior lateral teeth. Right valve with single, slightly bifid cardinal tooth and anterior and posterior lateral teeth. Anterior adductor muscle scar short, barely detached from pallial line, posterior adductor scar ovoid. Pallial line entire. Inner shell margin finely denticulate.

Distribution.

South Atlantic: around Falkland Islands ( Dell 1964), Argentina, outer continental shelf off Buenos Aires ( Roux et al. 1993); Patagonia shelf, South Georgia, South Orkney Islands ( Zelaya 2005). Depth range 100-545 m (distribution map at https://www.gbif.org/species/6523387).

Figures

Figure 13. Notocina falklandica (Dell, 1964). A-D Holotype of Epicodakia falklandica (NHMUK 1962857 / 1) exterior and interior views of both valves, L 2.5 mm E-J N. falklandica paratype (NHMUK 1962858) Falkland Islands, Discovery stn WS 214, 208 m E exterior of left valve, L 1.9 mm F, G interior of left and right valves, L 2.3 mm H dorsal view, L 1.9 mm I protoconch, arrow indicates boundary of P 1 and P 2 J detail of E showing punctate microsculpture. Scale bar: 100 µm (I); 20 µm (J).