Cyclopecten secundus (Finlay, 1926)
FINLAY, H. J. 1927. New specific names for Austral Mollusca. Transactions of the Royal Society of New Zealand, 57: 488-533, pls. 18-23. [p. 453]
1926 Cyclochlamys secundus Finlay, 1926
1927 Pecten (Cyclopecten) hinemoa Mestayer, 1927
1927 Pecten (Cyclopecten) hinemoa Mestayer, 1927
Pecten aff. transenna Suter; M. K. Mestayer, 1919, New Species of Mollusca, from various Dredgings taken off the Coast of New Zealand, the Snares Islands, and the Bounty Islands, plate 8, figure 11.
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«True Cyclopecten has not yet been recorded from New Zealand, though an undescribed species like the Australian favus and obliquus; is known to me from deep water in the North. The name "Pecten aviculoides Smith," included by Suter, may be easily dismissed; the type is from a locality a third of the globe distant, and Suter's identification is probably based on a juvenile Chlamys convexus.
Pecten transenna Suter has a peculiar facies quite different from that of true Cyclopecten; it is rhomboidal, the ears are not marked on the right valve and only slightly on the left, and both valves have the same sculpture of strong, rather distant nodulous ribs, while the texture of the shell differs from that of Cyclopecten, being similar to that of a young Chlamys. I supply for it the new generic name Cyclochlamys, and mention as a second member a shell described and well figured by Miss Mestayer (Trans. N.Z. Inst., vol. 51, p. 135, 1919), but misidentified by her as Suter's species; it differs from transenna in its much larger size, and in having about twice as many ribs. I propose for it the name Cyclochlamys secundus n. sp. Suter's drawing of transenna gives the appearance of his species quite well, and his specimens were adult, numerous topotypes I have examined not reaching any larger size.» HAROLD JOHN FINLAY, 1926
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«Description
Shell up to 3.70 mm high, subcircular, equivalve (relatively narrow, thin ventral margin of right valve disintegrating post mortem: thickened inner part c. 80% height of left valve), almost equilateral, left valve considerably more convex than weakly convex right valve, anterior auricle larger than right; some specimens with a single, incipient posterior internal radial rib on left valve; colourless, translucent. Prodissoconch 270–300 μm long, sharply delineated, D-shaped, moderately convex, inner part very finely malleated. Dissoconch left valve sculptured throughout with strong commarginal lamellae, and radial riblets of similar size to lamellae; strong, rounded, ventrally-projecting scales at intersections; early dissoconch with addition of very fine interstitial radial threads. Commarginal lamellae commencing immediately, number and spacing extremely variable: before appearance of radial riblets, ranging from as few as 6 with interspaces 2–3x width of each lamella, up to 25 with interspaces narrower than each lamella; after appearance of radial riblets about as widely separated as radials to less than half this width apart. Radial riblets commencing 0.40–1.00 mm from tip of prodissoconch, multiplying by intercalation, 12–15 on disc of specimens about 2 mm long, 1–4 on posterior auricle and 2–4 on anterior auricle. Right valve disc sculptured throughout with regularly spaced commarginal riblets. Anterior auricle and byssal fasciole separated from disc by sharply incised groove, auricle sculptured with fine commarginal lamellae alone, or (typically) with 4–10 fine, weakly beaded radial threads; posterior auricle continuous with disc, sculptured with commarginal growth lines, with or without addition of up to 3 weakly beaded radial threads. Byssal fasciole narrow. Distribution
Three Kings Islands, off Whangaroa, and Ranfurly Bank, East Cape, northern New Zealand, 20–622 m; taken alive at 37–221 m from comminuted bryozoan/shell substrata (Fig. 18). Remarks
Cyclopecten secundus is distinctive among propeamussiids from the New Zealand region in the strong reticulating commarginal and radial sculpture, with strong, rounded scales at the intersections. There is a superficial similarity to strongly sculptured forms of Cyclochlamys transenna with few radial ribs, but Cp. secundus is immediately separable by the more equilateral shape, and the sculpture of the right valve comprises commarginal threads rather than hexagonal prisms. Cyclopecten secundus is closely similar to Cp. cancellus Dijkstra, 1991 (tropical Indo-West Pacific), in gross facies, but the latter species differs principally in lacking scales at the intersections of the primary sculptural elements.» DIJKSTRA, H. H. & B. A. MARSHALL. 2008. The recent Pectinoidea of the New Zealand region (Mollusca: Bivalvia: Propeamusiidae,Pectinidae and Spondylidae). Molluscan Research, 28 (1): 1-88, figs. 1-70. [p. 21]
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Cyclopecten secundus (Finlay, 1926); H. H. Dijkstra & B. A. Marshall, 2008, The recent Pectinoidea of the New Zealand region, figures 19A-19E.
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«The right valve of this species is still ullknown. In the left valve the radial sculpture is most prominent but the concentrics are also very strong, the two systems forming a strongly netted effect. The shell is much more nearly equilateral than transenna. The species does not appear to have been re-collected, the type remaining unique.
Locality: Six and a half miles off the North Cape in 75 fathoms (type).» DELL, R. K. 1956. The archibenthal Mollusca of New Zealand. Dominion Museum Bulletin, 18: 1-235, pls. 1-25, text-figs. 1-6. [p. 23]
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