Chlamys iboibo Kurata & Kimura in Kimura, 1951
KIMURA, T. 1951. Some pectinids and a limid from the Jurassic Torinosu group in Japan. Journal of the Faculty of Science, University of Tokyo [Section II: Geology, Mineralogy, Geography, Seismology], 7 (6-10): 337-350, pI. 1 [p. 339, pl. 1, figs. 2-4]
1951 Chlamys iboibo Kurata & Kimura in Kimura, 1951
T. Kimura, 1951, plate 1.
|
«Description:— Shell small, nearly flat, broadly ovate, slightly oblique, sub-equilateral, sub-equivalve, but ornaments of the two valves are quite different. Ear subequal or anterior ear thrice longer than the posterior, ornamented with many crowded concentric ribs and two or more fine radial ribs; several nodes seen on the radials, but much smaller than those of the shell proper.
Left valve ornamented with 11 principal ribs, 8 riblets and concentric striae; one riblet in each interspace between the ribs, except those among the posterior three ribs; about 15 or more spines or nodes on the ribs prominent, wider than the ribs, aligned regularly and alternately with those on the neighbouring ribs; riblets smooth and about a half to two-thirds as broad as the ribs; furrows among them approximate to the riblets in breadth; concentric lines seen on the riblets and furrows, especiaIIy distinct on the latter. Right valve with 7 or 8 ribs which are bifurcating near the umbo; among them furrows deep and a little wider than the ribs; one or two ribs near the lateral peripheries not forking; all ribs with nodes like that of the left valve. Comparison:— The surface ornamentation is most. characteristic of this species. Though closely alIied to Pecten (Chlamys) asperulinus STOLITZKA (1882, p. 432, pI. 31, figs. 10, 11, pl. 44, fig. 5), it has a smaller number of nodes and more developed ornamentation. Chlamys etiveyensis DE LORIOL by DECHASEAUX (1936, pI. 3, figs. 3, 4) somewhat resembles this species, but can easily be distinguished from the latter by the absence of any riblet and more numerous radial ribs.
Occurrence:— Mimikire and Iigamori.» NOBUO KURATA & TOSHIO KIMURA, 1951
|
«One external and internal moulds of a left valve and two broken internal moulds of right valves are at hand. Radial 10 ribs on right valve are bifurcating near umbo and their interspaces on ventral side equally spaced. Some Sakamoto specimens are about twice as large as the Sakawa form.
Occurrence:— Locs. 8, 11.» TAMURA, M. 1959. Taxodonta and Isodonta from the Upper Jurassic Sakamoto formation in central Kyushu, Japan. Transactions and Proceedings of the Palaeontological Society of Japan [N. S.], 34: 53-65, pI. 6. [p. 57]
|
Chlamys (Chlamys) iboibo Kurata & Kimura; M. Tamura, 1959, Taxodonta and Isodonta from the Upper Jurassic Sakamoto formation in central Kyushu, Japan, plate 6, figures 35, 36.
|