Cyclochlamys nepeanensis Pritchard & Gatliff, 1904
PRITCHARD, G. B. & J. H. GATLIFF. 1904. On some new species of Victorian Mollusca, No. 7. Proceedings of the Royal Society of Victoria [New Series], 17: 338-339, pl. 20. [p. 338, pl. 20, fig. 5]
1904 Cyclopecten nepeanensis Pritchard & Gatliff, 1904
G. B. Pritchard & J. H. Gatliff, 1904, plate 20.
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«Description.— Shell very minute, white, thin and translucent, coraparatively dull externally, but shining rather strongly internally. To the naked eye the shell is slightly oblique, convex, and nearly orbicular, and owing to its minuteness and delicacy no sculpture is ordinarily visible, but in strong sunlight an extremely delicate radial and concentric sculpture is just discernible. Under a pocket lens the umbos are acute and prominent, hinge line straight, and falling very little short of the full length of the valve, auricles relatively large and subequal, with radiating and concentric sculpture, the former being much the stronger. The whole surface of the shell shows a delicate tesselation due to the regular radial and concentric threads, the radial threads numbering from about fifteen at the middle of the valve to about thirty at the ventral margin, intermediate threads making their appearance as the valve grows; the concentric threads number from about fifteen to twenty.
Dimensions.— Length, 1.5 to 2.5 mm.; height, 1.5 to 2.5 mm. Locality.— Back Beach, Point Nepean. Observations.—Three species of this genus have already been been clese-ribpfl tioni Australia: C. murrayi, Smith, in the Challenger Report, and C. favus, Hedley, and C. obliquus, Hedley, in the Memoirs of the Australian Museum. Our species, though closely related in many respects to the above, yet appears to be quite distinct from any of them. We have submitted specimens to Mr. Hedley, and he has kindly compared them with the types as those named by him, and he considers that ours is different.» GEORGE BAXTER PRITCHARD & JOHN HENRY GATLIFF, 1904
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«Description. Shell small, fragile, up to c. 2 mm high, hyaline or opaque, valves dissimilar in shape, size and sculpture; protruing conical prodissoconch of left valve with prominent reticulate sculpture. Prodissoconch 245–250 μm wide; of right valve c. 135 μm high, weakly convex, without central projection; of left valve with prominent, narrow, central projection with concave outlines, protruding c. 90 μm above surrounding prodissoconch margin.
Left valve slightly larger and more inflated than right valve, with prominent reticulate sculpture; auricles almost equal, weakly demarcated from disc, with some commarginal lines. Right valve smooth apart from faint hexagonal microsculpture. Anterior auricle with closely spaced commarginal lamellae. Byssal notch well developed. Habitat. Living in the sublittoral zone amongst rubble on soft sediment (sand and mud).
Distribution. Queensland, W Victoria and the Tasman Sea (Middelton Reef and Lord Howe Island; 26–61.5 m, alive). The sole record from the Australian mainland south of Queensland is the type material, two beach specimens from Point Nepean, Victoria.
Remarks. Cyclochlamys nepeanensis is variable in shape (almost circular to slightly posteriorly oblique) with a variable reticulate sculpture on the left valve (weak to prominent). It was formerly synonymized with Chlamydella favus (Hedley, 1902) (as Cyclochlamys; Dijkstra, 1995b: 40). However, the two species have different prodissoconchs on the left valve, i.e., conical in Cyclochlamys nepeanensis and weakly inflated in Chlamydella favus, demonstrating that they belong in different genera.»
DIJKSTRA, H. H. & A. G. BEU. 2018. Living scallops of Australia and adjacent waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae). Records of the Australian Museum, 70 (2): 113-330, figs. 1-102. [p. 158]
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Cyclochlamys nepeanensis (Pritchard & Gatliff); H. H. Dijkstra & A. G. Beu, 2018, Living scallops of australia and adjacent waters, figures 23C, 23F, 23H–23J.
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