Cyclopecten textus Dijkstra & Marshal, 2008
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, figs. 17C-17G, 18]
2008 Cyclopecten textus Dijkstra & Marshal, 2008
H. H. Dijkstra & B. A. Marshall, 2008, figure 17.
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«Type material
Holotype (lv) NIWA and 4 paratypes (pr, NMNZ M.155876; 3 v NIWA); Lord Howe Rise, 34º31.5’S, 166º21’E, 2928–2930 m, 23 Sep. 1982, RV Tangaroa (stn U195). Material examined
The type material (see above). Description
Shell up to 12.5 mm high, subcircular, equivalve (relatively narrow, thin ventral margin of right valve disintegrating post mortem), almost equilateral, left valve distinctly more convex than right valve, auricles dissimilar in shape, anterior auricle larger than posterior one, umbonal angle c. 120º, no internal riblets, resilifer broadly triangular, translucent white. Prodissoconch unknown (etched away). Dissoconch left valve strongly and crisply reticulately sculptured throughout by narrow radial ribs and higher commarginal lamellae; fine solid nodules at intersections, stronger on anterior and posterior end; radials and commarginals equally spaced on central part of disc, commencing immediately. Radials gradually enlarging, at first much weaker than commarginals and diverging in ‘camptonectes’ pattern, those on central third of disc enlarging throughout ontogeny, those on anterior and posterior thirds vanishing and replaced by normally diverging radials at about 2 mm from tip of prodissoconch, at which point radials and commarginals are similar. Commarginal lamellae strong and rather regularly spaced from initiation and throughout on central part of disc, closer after about 10 mm height and on sides. Auricular sculpture similar to that of disc. Right valve sculptured with commarginal lirae, delicate and closely spaced (c. 14 per mm) near umbonal area, coarser and wider apart on central part of disc (c. 6 per mm). Posterior auricle continuous with disc, sculptured with fine, closely spaced commarginal lamellae, and 5 radial threads; anterior auricle and byssal fasciole separated from disc by sharply incised groove, sculptured with prominent commarginal lamellae and 10 crowded radial threads with nodular intersections. Byssal notch moderately deep, byssal fasciole small. Distribution
Lord Howe Rise, 2928–2930 m (very fresh shells only) (Fig. 18). Remarks
Cyclopecten textus is similar in shape and sculpture to Cyclopecten kapalae (see above) but differs in attaining larger size (height up to 12.5 mm, versus 6 mm), in having stronger sculpture on the left valve, and in having nodules at the intersection of the commarginal and radial sculpture. It differs from Cp. kermadecensis (see above) in being more rounded, with weaker commarginal lamellae and defined radial riblets, and from Cp. cancellus Dijkstra, 1991 (Indonesia and Vanuatu) in attaining much larger size and in having more finely reticulate sculpture. Etymology
Web or tissue (Latin), alluding to the sculpture of the exterior of the left valve.» HENK H. DIJKSTRA & BRUCE A. MARSHALL, 2008
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