Annachlamys okinawaensis Noda, 1991
NODA, H. 1991. Molluscan fossils from the Ryukyu Islands, Southwest Japan. Part 3. Gastropoda and Pelecypoda from the Yonabaru Formation in the southwestern part of Okinawa-jima. Science Reports of the Institute of Geosciences, University of Tsukuba [Section B], 12: 1-63, figs. 1-18. [p. 19, figs. 8.6a-8.9]
1991 Annachlamys okinawaensis Noda, 1991
H. Noda, 1991, figure 8.
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«Description; Shell moderate in fan-shaped. Right valve; Shell slightly inflated. Shell length nearly equal with shell height. External surface on and interspaces of radial ribs sculptured with fine concentric growth lines. Radial ribs narrowly elevated with roof-like profile on early to middle parts of disc and become wide and round profile on near ventral margin. Radial ribs about 16 to 17 except for small riblets on both anterior and posterior extremities. Both auricles small in trigonal sculptured with 4-5 narrowly elevated radial ribs crossed by fine concentric growth lines. Hinge line not straight. Both sides of hinge line higher than beak. No ctenolium tooth at byssal notch. Inner surface from ventral margin to middle part crenulated by bi-ridged radial ribs according to external ribs. Trigonal resilial pit deep with wide angle. Cardinal crura distinct with distinct ridges. Muscle scar well impressed on middle to posterior sides of disc. Left valve also similar with those of right valve. Shell nearly flat with 16 to 17 radial ribs being slightly narrow and flat crossed over concentric growth lines.
Comparisons; The present species is characterized by its 16-17 radial ribs crossed with distinct concentric growth lines. The newspecies is distinguished from Annachlamys yaquenaensis Noda in having nearly twice radial ribs.
Cryptopecten sp. described with illustration in this article has resemblance with the present species in its shell form and the number of radial ribs, but the new species has no any ridge on the radial ribs. Localities; Loc. nos. 41U (rare), 42U (rare)*, 48 (rare), 50 (rare), 265 (rare)*.» (*; illustrated specimen in Figures) HIROSHI NODA, 1991
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«The fossil record of Annachlamys appears to be limited to the Neogene (Miocene to Pleistocene) of the Indo-Pacific region. Examples are Annachlamys okinawaensis Noda, 1991, from the Ryukyu Islands, southwest Japan, Pecten (Chlamys) suvaënsis Mansfield, 1926, and Pecten (Chlamys) nausorensis Ladd, 1934 from the late Miocene or early Pliocene of the Fiji Islands, and Pecten murrayanus Tate, 1886, from the Morgan Limestone of South Australia. The last species is possibly the oldest known Annachlamys.»
WALLER, T. R. 2006. New Phylogenies of the Pectinidae (Mollusca: Bivalvia): reconciling Morphological and Molecular Approaches. In S.E. Shumway & G.J. Parsons (Ed.): Scallops: Biology, Ecology and Aquaculture: 1-44. [p. 27]
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