Pusillolucina pusilla Glover & Taylor, 2016

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

Pusillolucina pusilla Glover & Taylor, 2016 Figs 8 A–F

Pillucina pusilla Glover and Taylor 2016: 159, figs 41D, 44 A–L.

Type material.

Holotype: MNHN-IM-2000-26591. Paratypes: 6 (MNHN-IM-2000-26592, IM-2009-10362). L 1.2-1.8 mm.

Type locality.

Philippines, Bohol Island, Manga, 9°41.1'N, 123°51.4'E, 3-4 m, mud, [PANGLAO 2004: stn S19].

Description.

Very small, glossy, L to 1.8 mm, sub-circular, higher than long, inflated. Umbones prominent. Sulci and dorsal areas poorly defined. Sculpture of thin commarginal lamellae elevated to anterior and posterior, with 17-25 low, rounded radial ribs, divaricate in anterior part of shell. Juvenile shell with elevated commarginal lamellae but no radial ribs. Microsculpture of fine growth increments only. Protoconch P1 +P 2 = 134 µm, P2 with numerous growth increments. Lunule broadly lanceolate, depressed, asymmetric, larger part in left valve. Ligament short, internal, oriented parallel to cardinal teeth. Hinge: right valve with single cardinal tooth, large anterior lateral tooth and posterior lateral tooth consisting of four or five cusps, left valve with two cardinal teeth, the anterior larger, anterior lateral socket, posterior lateral with sockets for cusps of the right valve. Anterior adductor scar very short, barely detached from pallial line, pallial line irregularly discontinuous. Inner shell margin coarsely crenulate.

Figures

Figure 8. Pusillolucina pusilla and P. denticula. A-D Pusillolucina pusilla (Glover & Taylor, 2016) A Pillucina pusilla Holotype (MNHN IM- 2000 - 26591) Philippines, Bohol Island, L 1.2 mm B holotype dorsal view C, D P. pusilla interior of left and right valves, paratype (MNHN IM- 2000 - 26592), L 1.05 mm E, F detail of hinge teeth in C, D. G-K Pusillolucina denticula (Glover & Taylor, 2001) Durban Bay, South Africa G exterior of right valve, paratype (NMSA), L 2.9 mm H, I interior of left and right valves, holotype (NMSA), L 3.5 mm J, K detail of hinge teeth.