Parvamussium aldeynzeri Dijkstra, 2004
DIJKSTRA, H. H. 2004. Two new species of Pectinoidea (Bivalvia, Propeamussiidae and Pectinidae) from the Philippines. Basteria, 67 (3-4): 127-133, figs 1-17. [p. 128, figs. 7-17]
2004 Parvamussium aldeynzeri Dijkstra, 2004
2005 Parvamussium toyoshiomaruae Okutani, 2005
2005 Parvamussium toyoshiomaruae Okutani, 2005
H. H. Dijkstra, 2004, figures 1-17.
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«Material. – Philippines, Bohol, Panglao Island, Loac, 9°35'N, 123°49'E, offshore, tangle nets, bathyal depth, alive (ZMA Moll. 4.03.020/holotype [pr], 4.03.021/2 paratypes [pr]).
Description. – Shell small, fragile and flattened, up to c. 10 mm high, subcircular, somewhat higher than wide, inequivalve, inequilateral. Left valve slightly more convex than right one. Anterior auricles larger in size and shape than posterior ones. Umbonal angle c. 90°. Colour creamy white, semi-transparent.
Left valve with 13-14 hollow radial lirae, starting at 3 mm shell height and increasing with secondary intercalated lirae to the ventral margin. Umbonal area glossy (2 mm), surface nearly smooth; weak, delicate, commarginal sculpture laterally; ventral margin somewhat undulated. Anterior auricle dorsally somewhat commarginally undulated (flat in paratypes), with a few very weak radial riblets and closely spaced commarginal lamellae laterally, posterior auricle smooth and flat. Right valve with very weak, closely spaced, cornmarginal lamellae, ventrally more prominent. Anterior auricle with 5-6 delicate radial riblets and commarginal lamellae laterally; posterior auricle smooth, dorsal margin squamose. Marginal apron (2 mm) fragile and often damaged or broken off. Hinge line straight. Byssal notch shallow. Internal ribs eleven, starting at 2 mm shell height. Dimensions of holotype: H 10.2 mm, W 10.1 mm, C 2.1 mm. Distribution. – Only known from Bohol, Philippines. Comparison. – P. deynzeri [sic] closely resembles Parvamussium undosum Dijkstra, 1991, known from Indonesia, but differs by its larger size (10 mm, versus 8 mm in P. undosum), a smooth surface (P. undosum has a strongly developed commarginal sculpture on the disc and the auricles), a larger glossy umbonal surface (2 mm, versus 1 mm in P. undosum), a squamous dorsal margin of the right valve (very weakly developed in P. undosum), and a different colour of semi-transparent creamy white (white and opaque in P. undosum). Etymology. – This new species is named after Mr. Al Deynzer of Sanibel Island (Florida, USA).» HENK H. DIJKSTRA, 2004
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