Cyclopecten incubans Barnard, 1964
BARNARD, K. H. 1964. Contributions to the knowledge of South African marine Mollusca. Part V. Lamellibranchiata. Annals of the South African Museum, 47 (3): 361-593, figs. 1-39. [p. 432]
1964 Cyclopecten incubans Barnard, 1964
Cyclopecten incubans Brnrd.; K. H. Barnard, 1969, Contributions to the knowledge of South African marine Mollusca, Part VI, Supplement, figures 29a-29c.
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«Subcircular, thin, translucent, inequivalve, right valve smaller than left and slightly less convex, not flattened or turned up at margin, ears distinct, byssal sinus well marked; earliest part of right valve with extremely fine radial striae, later replaced by extremely fine and close concentric striae, radial ribs and (major) growth-lines very obscure, anterior ear obscurely ribbed, posterior ear concentrically lamellate, interior smooth. Left valve with concentric lamellae beginning at about 0.4–0.5 mm. alt., very fine radial ribs beginning at about 0.5–0.75 mm., and intermediaries almost immediately thereafter, at margin about 45–50 ribs, not very regularly spaced, often in pairs or 3–4 fine ones between two stronger ones, sculpture cancellate, but the concentric growth-lines often stronger than the ribs, especially on earlier part of the shell, intersections crenulate, scarcely squamulose except feebly so on posterior part; ears finely cancellate, the concentrics stronger than the radials; interior smooth with very shallow grooves corresponding with the external ribs, no radial costae, margin smooth. White, translucent.
Largest single valve: length 5, alt. 4-5 mm.; a double shell: left valve 4 X 3.5, right valve 3.3 X 3 mm. The specimen from off Cape Point and one of the Cape St. Blaize examples contained bivalved juveniles, about 20 in the former, 15 in the latter. Minutely radially striate, hinge-line 0.3 mm. Off Cape St. Blaize, 125 fathoms, 2 living and 8 valves (Types); Cape Point N.E. J N. 19 miles, 145 fathoms, one living (S. Afr. Mus. Nos. A9493 (Types), A9494. P.F. coll.). 34° 17' S., 17° 53' E., 320 metres, one living (U.C.T.). Remarks. So far as I am aware incubation has not been recorded in the Pectinidae, though some species are known to be monoecious, others dioecious. The radial ribbing on the left valve is variable, no two specimens being exactly alike.» KEPPEL HARCOURT BARNARD, 1964
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«Distribution and ecology. C. incubans is known from the eastcoast of South-Africa (Indian Ocean), living on a muddy sand bottom from sublittoral to bathyal depth.
Remarks. C. incubans has almost the same morphological characters as the SIBOGA specimen, but subcircular and more coarsely sculptured, caused by some radial riblets. C. cf. incubans bears a cancellated structure near the ventral margin, caused by fine radiation and concentric lamellae.»
DIJKSTRA, H. H. 1990. Three new pectinacean species from the Indonesian Archipelago collected during the Siboga Expedition (1899-1900), with additional information and corrections on the previous report (Mollusca: Propeamussiidae, Pectinidae). Beaufortia, 40 (1): 1-14, pls. 1, 2. [p. 5]
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Cyclopecten (Cyclopecten) cf. incubans Barnard, 1964; H. H. Dijkstra, 1990, Three new pectinacean species from the Indonesian Archipelago collected during the Siboga Expedition, plate 2, figure 10.
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