Cyclochlamys munida Dijkstra & Marshall, 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. 32, figs. 26C, 26F, 26G]
2008 Cyclochlamys munida Dijkstra & Marshall, 2008
H. H. Dijkstra & B. A. Marshall, 2008, figure 26.
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«Type material
Holotype (lv) NMNZ M.138430; Bradshaw Basin floor, Bradshaw Sound, SW South Island, New Zealand, 45º17.3’S, 167º02.6’E, 415 m, 31 May 1997, RV Munida. Paratypes: Thompson Basin floor, Thompson Sound, 45º14.38’S, 166º58.87’E, 340–362 m (2 v, M.150527). Material examined
The type material (see above). Description
Shell up to 2.15 mm high, slightly posteriorly oblique, about as wide as high, translucent white. Prodissoconch 430 μm long, bounded by strong, flange-like commarginal lamella, roundly conical; PI 200 μm long, D-shaped (i.e. valve margins), smooth, weakly swollen, bounded by prominent upturned flange with rounded rim; PII sides weakly concave, reticulately sculptured with crisp radial threads, and weaker, closer, less sharply defined commarginal riblets. Dissoconch left valve disc and auricle sculpture commencing immediately, crisp; comprising widely and rather irregularly spaced, narrow, commarginal lamellae, traversed by slightly finer radial riblets that multiply by intercalation and curve in ‘camptonectes’ pattern, very small rounded nodules at intersections; interspaces widest over centre of disc. Posterior auricle distinctly larger than anterior auricle. Right valve unknown. Distribution
Bradshaw Sound, New Zealand, 340–415 m, shells only (presumably living on the fjord walls, and quite likely to have been translocated down them) (Fig. 27). Remarks
Compared with young specimens of Cyclochlamys aupouria (allopatric), which it most resembles, Cc. munida differs in having a larger PI (width 200 μm versus 170 μm) with a broadly rounded rather than strongly projecting central area, in that PII, though of similar size, has only a single (terminal) commarginal lamella, and in that the commarginal lamellae on the dissoconch are weaker and distinctly nodular at intersections with the radial riblets and curve in a camptonectes pattern. Cyclochlamys aupouria and Cc. munida (like perhaps Cc. irregularis and Cc. austrina) may be allopatric phylogenetic sister taxa. Etymology
After Otago University’s research vessel Munida, from which the type material was dredged (noun in apposition).» HENK H. DIJKSTRA & BRUCE A. MARSHALL, 2008
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