Cyclochlamys aupouria (Powell, 1937)
POWELL, A. W. B. 1937. New species of marine Mollusca from New Zealand. Discovery Reports, 15: 153-222. [p. 167, pl. 47, figs. 1, 2]
1937 Cyclopecten (Cyclochlamys) aupouria Powell, 1937 [partim]
A. W. B. Powell, 1937, plate 37.
[not figure 1: Cyclochlamys secundus, Finlay, 1926; fide H. H. Dijkstra & B. A. Marshall, 2008, p. 20] |
«Shell minute, white, inequivalve and inequilateral, thin and fragile, with discrepant sculpture on the two valves. Left valve sculptured with thin regularly spaced concentric lamellae and fine interstitial radial threads. The concentric lamellae are about six per millimetre. Ears subequal, small, not distinctly marked off from the disc. Beaks raised in the form of small rounded knobs. Right valve flatter than the left and sculptured with very much finer thread-like concentric lines, about twenty per millimetre, interspaces with dense microscopic radials. Anterior ear with five thickened concentric folds, posterior with a well-defined byssal sinus, several indistinct radials and radial crenulations along the hinge margin. Interior smooth, hinge line straight with a minute triangular resilium.
Diameter: antero-posterior 3.4 mm., dorso-ventral 2.9 mm.; thickness 0.6 mm. (Holotype, left valve). Habitat: Off Three Kings Islands, St. 933, 260 m. » ARTHUR WILLIAM BADEN POWELL, 1937
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«Description
Shell up to 4 mm wide, subcircular, equivalve (broad, thin ventral margin of right valve disintegrating post mortem: thickened inner part 81–83% height of left valve), left valve somewhat more convex than right valve, slightly wider than high, umbonal angle c. 107º; colourless and translucent. Prodissoconch 340–400 μm long (brooded), bounded by second commarginal lamella after PI flange; PI D-shaped (i.e. valve margins), c. 150 μm long, essentially smooth, tip prominent and roundly coeloconoid, bounded by prominent, rounded, upturned flange; PII convex, sculpture indistinguishable from that of adjacent dissoconch, with 2 upturned, flange-like commarginal lamellae (outer bounding dissoconch), finer, crisp radial riblets, and yet finer, closer commarginal riblets. Dissoconch left valve disc and auricle sculpture commencing immediately, crisp throughout; comprising widely spaced, high, thin, commarginal lamellae; and finer, more closely spaced radial threads that multiply by intercalation (18–21 per mm on central disc). Auricles of similar size. Right valve disc and all but dorsal border of posterior auricle with outer layer of commarginally elongate, hexagonal prisms that form broad, flexible ventral apron. Posterior auricle in some specimens with 1 or 2 radial threads beside dorsal margin. Anterior auricle sculptured throughout with commarginal lamellae and 4 or 5 finer radial threads. Byssal notch of moderate depth, byssal fasciole rather broad. Distribution
Three Kings Islands, and NE North Island, New Zealand, 79–805 m; taken alive at 79–442 m from hard substrata (Fig. 21). Remarks
Cyclochlamys aupouria broods its young. One adult specimen (height 2.4 mm) had a brood in two size classes, c. 180 μm wide (10), and c. 320 μm wide (6), congregated on the left and right sides respectively. Cyclochlamys aupouria is superficially similar to the south-eastern Australian species Cc. favus (Hedley, 1902) (= Cc. obliquus Hedley, 1902) in sculpture, but differs in attaining smaller size (height respectively up to 3.6 mm and 4.2 mm), and in having more widely spaced commarginal lamellae and much stronger interstitial radial lirae, and in being more nearly orbicular in shape, rather than markedly posteriorly oblique as in adult specimens of Cc. favus. They differ further in details of prodissoconch morphology, Cc. favus having a prominent radial rib on the left valve (but not the right), which is absent in the New Zealand species. Similarly sculptured species are described below.» 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. 23, 24]
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Cyclochlamys aupouria (Powell, 1937); H. H. Dijkstra & B. A. Marshall, 2008, The recent Pectinoidea of the New Zealand region, figures 20A-20G.
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«Powell described aupouria from disassociated left and right valves from off the Three Kings, naming the left valve as type. From the same locality he described and figured a right valve which he ascribed to secundus Finlay (described from the same general locality). From numerous deep water localities on the Chatham Rise and off Otago large numbers of disassociated valves have been obtained. All the left valves are referrable to the left valve of aupouria, Powell, but all the right valves are similar to that figured by Powell for secundus Finlay. These were the only two types of valves obtained at nine stations. The inescapable conclusion is that Powell inadvertently associated the wrong valves in describing aupouria) and that the true right valve of aupouria is that figured by him as secundus. In the present state of our knowledge of the group it is impossible to state with certainty to which species the valve figured as the right valve of aupouria should be attributed, but it appears very close to that of powelli n.sp.
The left valve has thin, regular, concentric lamellae with fine interstitial radials. Right valve sculptured with separated, dense, concentric threads in radial series. Localities: C.I.E. Station 4, Chatham Rise, in 200 fathoms; C.I.E. Station 5, Chatham Rise, in 300 fathoms; C.I.E. Station 34, east of the Forty Fours, in 130 fathoms; C.l.E. Station 40, south-east of Pitt Island, in 155 fathoms; C.I.E. Station 41, south-east of Pitt Island, in 330 fathoms; C.I,E, Station 44, north-east of Kaingaroa in 120-125 fathoms; C.I.E. Station 59, Chatham Rise, in 290 fathoms; Portobello Alert Station 54-9, off East Otago coast, in 250 fathoms; Portobello Alert Station 54-17, off East Otago coast, in 260-350 fathoms; B.S. 190, off East Otago coast, in 300 fathoms.» DELL, R. K. 1956. The archibenthal Mollusca of New Zealand. Dominion Museum Bulletin, 18: 1-235, pls. 1-25, text-figs. 1-6. [p. 22, 23]
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