Propeamussium rubrotinctum (Oyama in Kuroda, 1951)
OYAMA, K. 1951. Amusiinae in Japan. In: T. Kuroda (ed.), 1949-1953, Illustrated Catalogue of Japanese Shells, 216 p., 13: 79-86, pl. 13, text-figs. 1-4. [p. 81, pl. 13, figs. 8-10]
1951 Parvamussium (Parvamussium) rubrotinctum Oyama in Kuroda, 1951
1984 Propeamussium (Propeamussium) stella Wang, 1984
1984 Propeamussium (Propeamussium) stella Wang, 1984
T. Oyama, 1951, plate 13.
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«Shell of moderate size, thin, ovate, compressed, subequilateral, subequivalves; ventral margin thin,and fragile with weak deposit of shell substances; anterior margin rounded; posterior margin weakly produced towards the postero-ventral part. Auricles small, anterior one larger than the posterior; anterior margin of the anterior auricle nearly vertical to the dorsal margin, while the posterior end of the hinge margin bluntly angulated to the posterior margin of the auricle. The hinge margin straigt, with indistinct crenations; byssal sinus poorly developed. Surface of the left valve smooth, some indistinct concentric undulations are visible only; the right valve ornamentecl with distinct regular concentric ribs and also a single radial rib on the base of the anterior auricle. Internal lirae 18 in the left valve with additional shorter intercalated ones; in the right valve the number being 12 incluciing some shorter ones. The coloration differs in both valves: ground colour of the left valve is pale pellucid amber, tinted with fleshy apricot orange, in addition the white rays of the internal lirae are visible through it; that of the right valve is pale orange apricot, with miiky white rays are visible in same way.
Length 16.8 mm., height 16.3 mm., breadth 4 mm. (figured specimen) Type locality: Gulf of Tosa, Shihoku. Distribution: Shikoku and Kyushu. Remark: internal lirae of the left valve of the holotype are extraordinarily 18 in number but in many specimens they are generally 12.» KATURA OYAMA, 1951
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«Description. — Shell fragile, transparent or opaque, subcircular, inequivalve, inequilateral, up to c. 20 mm high, left valve somewhat more inflated than right. Valves gaping laterally. Auricles relatively small and unequal. Umbonal angle about 90˚. Prodissoconch c. 200 μm in height. Colour of left valve with light orange patches and small white dots, right valve pale orange-tinted with translucent whitish internal radial riblets. Left valve sculptured with minute commarginal lamellae in late growth stage near the periphery, otherwise smooth and glossy with a few concentric plications, one or two delicate radial plicae near posterior margin. Auricles smooth.
Right valve sculptured with regularly spaced commarginal lirae and interstitial microscopic radial scratches. Auricles with commarginal striae and somewhat serrated on dorsal margin. Internal ribs generally 10, an auricular lira on each side. Internal ribs of right valve somewhat broader than of left valve. Resilifer triangular, elongate. Outer ligament rather broad. Hinge line straight. Small byssal notch, no ctenolium. Distribution. — Kii Peninsula (Japan) southwards to tropical West Pacific: 200-300 m (Hayami, 2000: 913); Indonesia: 210-268 m (Dijkstra & Kastoro, 1997: 250); Solomons, Fiji and Tonga: 300-869 m (Dijkstra & Maestrati, 2008: 84); New Caledonia and Loyalty Islands: 380-490 m (Dijkstra, 1995: 21); Norfolk Island: 280-350 m, dead (Dijkstra & Marshall, 1997: 79); Wallis and Futuna, and Vanuatu: 265-460 m (Dijkstra, 2001: 81). Present material from the Philippines alive in 163-437 m (minimum depth range). The bathymetric range of live-taken specimens is now extended to 150-869 m. Remarks. — Wang (1984a) described a new species, P. stella, from the South China Sea, which is morphologically similar to the present species. He compared it with P. caducum and overlooked the similar congeneric species P. rubrotinctum, known from the tropical western Pacific, and the closely allied congener Propeamussium steindachneri (Sturany, 1901), known from the Red Sea and the western Arabian Sea (see Dijkstra 1995: 23; Dijkstra & Marshall, 2007: 79). The present specimens are similar to Oyama's original description, but the original figured specimen (type material untraceable) is somewhat more circular of shape and has interior interstitial rudimentary riblets. Oyama reported (1951: 81) other specimens lacking intercalated riblets, just as in the present material from the Philippines.» DIJKSTRA, H. H. 2013. Pectinoidea (Bivalvia: Propeamussiidae and Pectinidae) from the Panglao region, Philippine Islands. Vita Malacologica, 10: 1-108, pls. 1-32, 2 tabs. [p. 14]
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Propeamussium rubrotinctum (Oyama, 1951); H. H. Dijkstra, 2013, Pectinoidea from the Panglao region, Philippine Islands, plate 1, figures 3a, 3b.
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