Anguipecten pacificus Dijkstra, 2002
DIJKSTRA, H. H. 2002. A new species of living scallop of the genus Anguipecten (Bivalvia, Pectinidae) from the tropical Indo-Pacific. Basteria, 66: 139-142. [p. 139, figs. 1-4]
2002 Anguipecten pacificus Dijkstra, 2002
H. H. Dijkstra, 2002, figures 1-9.
|
«Description. — Shell up to c. 60 mm high, solid, compressed, oblong, nearly equivalve and equilateral, right valve slightly more convex than left valve, auricles short and subequal, umbonal angle c. 85º, colour creamy, maculated with reddish dots and streaks, right valve somewhat paler.
Both valves radially undulated and sculptured with six prominent lirae; laterally an additional but weakly developed ridge. Interstices somewhat narrower than lirae. Secondary radial sculpture of small lirae (on right valve weaker) on the lirae and interstices, commence on the central part of the disc (c. 10 per lira) and extend to the ventral margin. Microsculpture consists of delicate and closely spaced commarginal lamellae throughout (c. 8-10 per mm in the central part). Anterior auricles very weakly sculptured with c. 10 radial riblets, posterior auricles nearly smooth. Inner surface plicated, more prominently so near periphery. Resilifer triangular. Byssal notch, fasciole and ctenolium lacking. Cardinal crura rather broad with closely and vertically set small ridges. Measurements of type series: holotype H 40.2 mm, W 35.8 mm; largest paratype H 60.5 mm. Distribution. — Eastern Indonesia (Kai Islands) and French Polynesia (Marquesas Islands); only dead taken bathyally (100-455 m), probably living sublittorally according to other data of Anguipecten species from the tropical Indo-Pacific (Dijkstra, unpubl. data). Comparison. — The specimens of A. pacificus from eastern Indonesia are somewhat atypical and slightly differ from the type material by having somewhat larger auricles with a shallow byssal notch on the right valve, which is lacking in typical material. Therefore these specimens are excluded from the type series. Anguipecten superbus (G.B. Sowerby II, 1842), known from the Indo-West Pacific, is very similar in size, shape, colour, and microsculpture, but differs from A. pacificus in having many more (18-23, A. pacificus: 6-7) radial lirae and a far less prominent secondary sculpture. Anguipecten lamberti (Souverbie, in Souverbie & Montrouzier, 1874), known from New Caledonia and Hawaiian Islands, differs in having numerous (c. 30) very compressed radial lirae and a weak secondary radial sculpture. Other morphological characters are similar to those of A. pacificus and A. superbus (size, shape, colour, and microsculpture). Anguipecten picturatus Dijkstra, 1995, also known from the Indo-West Pacific, differs from A. pacificus in size (up to c. 45 mm in height), in colour (more bright), in having more radial lirae (12-15), a coarser secondary radial sculpture, and a commarginal microsculpture in the late growth stage. Etymology. - From the Pacific Ocean (Lat. pacificus, adjective = pacific, peaceable). I am much indebted to Dr P. Bouchet (Muséum national d'Histoire naturelle, Paris) for submitting this pectinid material for study purposes. Thanks are also due to Mr P. Maestrati (Muséum national d'Histoire naturelle, Paris) and Mr RG. Moolenbeek (Zoological Museum, University of Amsterdam, Amsterdam) for their technical assistance and cooperation.» HENK H. DIJKSTRA, 2002
|