Cyclochlamys austrina 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. 24, figs. 21, 22A, 22C, 22D]
2008 Cyclochlamys austrina Dijkstra & Marshall, 2008
H. H. Dijkstra & B. A. Marshall, 2008, figure 22.
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«Type material
Holotype (subadult lv) NMNZ M.155885; Bradshaw Basin floor, Bradshaw Sound, SW South Island, New Zealand, 45º17.3’S, 167º02.6’E, 415 m, 31 May 1997, RV Munida. Material examined
The holotype (see above). Off Antipodes Islands, 49º40.19'S, 178º44.30'E, 113 m (1 v, M.158280). Description
Shell (holotype) 1.70 mm high, almost equilateral, umbonal angle c. 105º; colourless and translucent. Prodissoconch c. 360 μm long, boundary unclear, but presumably first prominent, flange-like, commarginal lamella; roundly conical, surmounted by flattened; PI Dshaped (i.e. valve margins), c. 120 μm long, smooth, bounded by rounded rim; PII weakly convex, sculptured with crisp, anastomosing radial threads. Dissoconch left valve disc and auricle sculpture commencing immediately, crisp, comprising widely and rather regularly spaced, high, thin commarginal lamellae, traversed by narrower, more closely spaced radial threads (c. 15 per mm on central disc) that multiply by intercalation, small conical nodules at intersections. Finer, more crowded, radial threads in ‘camptonectes’ pattern on dorsal half of posterior auricle, and on anterior and posterior quarters of disc. Posterior auricle distinctly larger than anterior auricle. Right valve unknown. Distribution
Bradshaw Sound, SW South Island, and Antipodes Islands, New Zealand, 113–415 m (single valves only) (Fig. 21). Remarks
Cyclochlamys austrina resembles Cc. irregularis n. sp. (see below) in having anastomosing radial riblets on the prodissoconch, relatively strong, widely spaced radial riblets on the dissoconch, and nodules where the radials cross the commarginal lamellae. Cyclochlamys austrina differs, however, in having a flattened instead of convex PI, finer primary sculpture on the dissoconch, and in having diverging secondary radials (camptonectes pattern) on the anterior and posterior sectors of the disc. The valve from the Antipodes Islands is 2.45 mm wide, and possibly adult. In the absence of the right valve, which is diagnostic for the genus, Cc. austrina is referred to Cyclochlamys because left valve morphology is more similar to that of Cyclochlamys species than to Cyclopecten. Etymology
Southern (Latin).» HENK H. DIJKSTRA & BRUCE A. MARSHALL, 2008
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