Cyclopecten kapalae Dijkstra, 1990
DIJKSTRA, H. H. 1990. A new species of scallop from off New South Wales, Australia (Bivalvia: Propeamussiidae). Journal ofthe Malacological Society of Australia, 11: 29-32, figs. 1-5. [p. 29, figs. figs. 1-5]
1990 Cyclopecten kapalae Dijkstra, 1990
H. H. Dijkstra, 1990, figures 1-5.
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«Description
Shell small, approximately 6 mm in height, but normally about 5 mm, somewhat higher than wide. Subcircular, inequivalve, left valve somewhat more convex than right one. Anterior and posterior auricles unequal, umbonal angle about 90°. Left valve cancellated on entire external surface, produced by fine irregular radial costae and concentric lamellae. Near umbonal area only concentric lamellae are present, radial ribbing beginning about 1 mm from umbonal top. Radial riblets and concentric lamellae most abundant near ventral margin. Between the cancellation surface is microscopically scratched. Anterior auricle has coarser concentric lamellae than posterior one, and without radial costae. No lirae visible on internal surface. Near ventral margin cancellated structure of external surface translucent, whereas central part of resilium often an opaque milky white. Hinge line straight; cardinal crurae have strong irregular grooves, widening at central part and narrowing at edge of hinge line. Resilial insertion triangular, somewhat overhanging. Umbonal top rises the hinge line. Right valve has concentric lamellae on entire external surface, somewhat larger and coarser at ventral margin. Posterior and anterior auricles also have concentric lamellae, somewhat more irregular on the latter. Microscopic scratches on surface between concentric lamellae. Near byssal fasciole two or three fine axial riblets are exposed, sometimes absent. Byssal fasciole small; byssal notch hardly distinguished from outer margin of anterior auricle. No ctenolium present on suture. Hinge line nearly straight, cardinal crurae similar to that of left valve. No internallirae. Coloration dirty to milky white, and sometimes translucent. Dimensions
Holotype: Height 5 mm, length 4.5 mm, diameter 1.2 mm. Para types: Height 2.5 to 6 mm, length 2.5 to 5.5 mm (valves). Holotype
Off Sydney, NSW, 33°31'-33'S, 152°08'-07'E, 914-907 m, 10 Dec. 1980, FRV 'Kapala' Stn. K80-20-08. AMS C. 155831.1. Paratypes
NSW: (All collected by FRY 'Kapala'). Off Port Kembla, 33°41'S, 151°56'E, 730 m, 5 Dec. 1977. Dredged; Stn. K77-23-04. 2 l.v. & 2 r.v., AMS C. 155837. Off Nowra, 34°50'S, 151°15'E, 841 m, 12 Dec. 1978. Dredged, Stn. K78-27-04. 3 l.v. & 5 r.v., AMS C. 155823. Off Nowra, 34°50'S, 151°13'E, 550 m, 12 Dec. 1978. Benthic sledge, Stn. K78-27-07. 1 l.v., AMS C. 155822. Off Sydney, 34°15'-12'S, 151°29'-31'E, 476 m, 14 Dec. 1978. Trawled, Stn. K78-26-17. 8 l.v. & 11 r.v., AMS C. 155832. E of Sydney, 33°33'S, 152°05'E, 750 m, 4 Dec. 1979. Benthic sledge, Stn. K79-20-03. 3 r.v. AMS C.155800. E. of Broken Bay, 33°32'S, 152°08'E, 914 m, 4 Dec. 1979. Benthic sledge, Stn. K79-20-05. 1 l.v. & 1 r.v., AMS C. 155813-14. Off Sydney, 33°32'-33'S, 152°08'-07'E, 914 m, 10 Dec. 1980. Dredged, Stn. K80-20-08. 5 l.v. & 5 r.v., AMS C. 155831.2. Distribution
The new species has been collected only from off New South Wales, Australia (33°31-34°50'S and 151°13-152°08'E), in coarse sand to fine ooze, with sediments. Remarks
Cyclopecten secundus Finlay, 1927 from New Zealand differs from C. kapalae by more pronounced cancellated sculpture with tubercles on the left valve, cancellated auricles, and a broader shell-disc. Cyclopecten bistriatus (Dall, 1916) is somewhat larger, to 7 mm in height and length, and lives in deeper water to 1500 m off California, USA. This species has also been reported from Sagami Bay, Japan (710-1385 m) by Okutani (1962; 18), no morphological differences between the Californian and Japanese species being recognized. Japanese specimens have finer cancellations on the entire surface of the left valve than C. bistriatus from California and C. kapalae. Cyclopecten bistriatus differs from the Japanese species and C. kapalae by more close-set radial riblets on the left valve. The morphological features of the right valve are almost similar in the three species.» HENK H. DIJKSTRA, 1990
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