Nanaochlamys notoensis otutumiensis (Nomura & Hatai, 1937)
NOMURA, S. & K. HATAI. 1937. A list of the Miocene Mollusca and Brachiopoda Collected from the Region Lying North of the Nanakita River in the Vicinity of Sendai, Rikuzen Province, Japan. Saito Ho-on Kai Museum Research Bulletin, 13: 121-145, pls. 17-21 [p. 130, pl. 18, fig. 7]
1937 Pecten (Swiftopecten?) otutumiensis Nomura & Hatai, 1937
1940 Pecten (Chlamys) kagamianus miyaguiensis Nakamura, 1940
1940 Pecten (Chlamys) kagamianus miyaguiensis Nakamura, 1940
S. Nomura & K. Hatai, 1937, plate 18.
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«Nom. Jap., Ôtutumi-kintyaku.
Shell rather small in size, triangularly ovate in outline, compressed, radially ribbed externally. Ribs rounded, strong, fivein umbonal area, immediately after each split into two subequal ones and tendency of tertiary bifurcation along ventral margin is seen; interspaces round-bottom, subequally spaced, and nearly equal to ribs in breadth; entire surface finely imbricated, both ribs and interspaces provided with a few radial riblets; anterior ear partly lost; posterior ear concavely truncated, sculptured with about three imbricated radial riblets; both sides of disc almost straight. Length ca. 40, height ca. 40, depth 10 mm.
The above description and measurements were based upon a single imperfect specimen of a left valve. It is unique by its radial ribs which remove it from the other species of the Japanese scallops hitherto described. It is, however, more or less similar to P. izuensis NOMURA and NIIN0 1) from the Miocene of Idu Peninsula in its general aspect, but that shell has no branching riblets.
Locality: Ôtutumi (rare), Reg. No. 5997.» 1) S. NOMURA and H. NIINO, Sci. Rep. Tohoku Imp. Univ., Ser. 2, Geol., Vol. 15, No.3, p. 197, pI. 11, figs. 9-13, 1932.
SHICHIHEI NOMURA & KOTORA HATAI, 1937
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«Although the type specimen consists of only a single left valve, its radial sculpture readily serves to remove it from its allied ones, which are such as Pecten notoensis YOKOYAMA and Pecten izuensis NOMURA and NIINO.
Although the writer failed to collect this rare species, it is here listed owing to its occurrence in the region studied. Details will be given when specimens accumulate. Locality:— Ôtutumi, Miyatoko-mura, Kurokawa-gun. Horizon:— Ôtutumi beds.» NAKAMURA, M. 1940. On some Pectinidae fossils from the Miocene deposits of the Tomiya Block, Miyagi-ken, Northeast Honsyû, Japan. Japanese Journal of Geology and Geography, 17 (1-2): 1-15, pIs. 1, 2. [p. 12]
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