Annachlamys Iredale, 1939
IREDALE, T. 1939. Mollusca. Part 1. Great Barrier Reef Expedition 1928-29, B.M.(N.H.). Sci. Repts., 5: 209-425 [p. 358]
«Genus Annachlamys nov.
Type: Pecten Leopardus Reeve. Medium-sized shells, both valves convex, but somewhat flattened umbonally and spreading laterally, compressed towards the edges, gaping a little dorsad, and subequilateral and a little inequivalve, the right valve less convex than, and clasped by the left valve. The sculpture consists of few stout radials overrun by densely packed concentric striae gaining strength ventrad, the ribs themselves sometimes flattening. The ears are subequal with no byssal gape nor ctenolium, and a juvenile radial sculpture disappears at an early stage, the surface being concentrically threaded as the valves. The valves inside are ribbed in the Amusioid, or better in the Notovolid manner, and there is present on each side an auricular nodule, but no auricular crura.
The hinge shows two cardinal crura, divergent and fairly strong, but a little variable, and coarsely striate; no rims to the ligamental pit, which is rather small and broad, the ligament rather narrow.» TOM IREDALE, 1939
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Pecten leopardus Reeve; L.A. Reeve, 1852-53, Monograph of the genus Pecten, Conchologia Iconica, plate 32, figure 145.
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H. H. Dijkstra & A. G. Beu, 2018, Living scallops of Australia and adjacent waters. Annachlamys flabellata (Lamarck), figures 1A, 1B; Annachlamys iredalei (Powell), figures 1C, 1F; Annachlamys kuhnholtzi (Bernardi), figures 1D, 1E, 1G, 1H.
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«Annachlamys Iredale, 1939: 358. Type species (by original designation): Pecten leopardus Reeve, 1853 (= Pecten flabellatus Lamarck, 1819); Recent, western, northern and eastern Australia.
Diagnosis. Pectinini with a sturdy, subcircular shell, up to c. 60 mm high and a few specimens up to >100 mm wide, with almost equally inflated valves, wider than high in late ontogeny, with numerous radial plicae (12–30), prominent widely spaced commarginal lamellae on disc and auricles of most adults (closely spaced in early ontogeny), auricles of most specimens without radial sculpture, internal rib carinae prominent. Hinge teeth weak. Byssal notch shallow; ctenolium obsolete or lacking in adult stage.
Distribution. Miocene–Recent (Beu & Darragh, 2001). Eurasia (Tethyan) (Hertlein, 1969), tropical western and southwestern Pacific, living in the littoral to sublittoral zones on soft sediment.
Discussion. Hertlein (1969: N355) treated Annachlamys as a subgenus of Chlamys, placed in the Chlamys group. Waller (1986: 40) considered Annachlamys to be a valid genus and placed it in tribe Decatopectinini. Following reconsideration of its phylogeny, Waller (2006a: 27, fig. 1.3) transferred Annachlamys to tribe Pectinini (as redefined by him, including Pecten and Gigantopecten) because of its change from close-set to far-set commarginal lamellae during ontogeny, and because it is most similar morphologically to Gigantopecten, a genus of Pectinini occurring in European Cenozoic rocks. The position of Annachlamys has varied significantly since. Sherratt et al. (2016) included both Annachlamys and Ylistrum in a minor basal clade in Decatopectinini, whereas Serb (2016) included Ylistrum in a basal clade of Decatopectinini but placed Annachlamys in Chlamydini (i.e., Pedini) between Semipallium dringi and Equichlamys bifrons. In our opinion the subfamily and tribe position of Annachlamys requires further molecular comparison. Here we retain it in Pectinini, awaiting a more final molecular phylogeny.
The living species of Annachlamys are: Annachlamys flabellata (Lamarck, 1819) from western, northern and eastern Australia and the adjacent Timor Sea and Coral Sea; A. iredalei (Powell, 1958) from the Coral Sea, New Caledonia, and southeastwards to the Kermadec Islands; A. kuhnholtzi (Bernardi, 1860) from Queensland, the Coral Sea and New Caledonia; A. reevei (A. Adams & Reeve, 1850) from the South China Sea, Indonesia to northern Australia; and A. striatula (Linnaeus, 1758) from the tropical western and southwestern Pacific to the eastern Indian Ocean (Dijkstra, 1999: 395). For fossil species of Annachlamys from southern Australia see Beu & Darragh (2001: 148).» 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. 210, 211]
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