Gloripallium crassivenium (Yokoyama, 1929)
YOKOYAMA, M. 1929. Pliocene Shells from near Nanao, Noto. Imperial Geological Survey of Japan, Report, 104: 1-7, pIs. 1-6. [p. 6, pl. 6, fig. 1]
1929 Pecten (Chlamys) crassivenius Yokoyama, 1929
1940 Pecten (Swiftopecten) nanakitaensis Nakamura, 1940
1954 Cryptopecten oyamadensis Hirayama, 1954
1940 Pecten (Swiftopecten) nanakitaensis Nakamura, 1940
1954 Cryptopecten oyamadensis Hirayama, 1954
M. Yokoyama, 1929, plate 6.
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«A single left valve lacking both hears.
Shell medium-sized, thick, compressed, orbicular, slightly higher than long, subequilateral, radiately ribbed. Ribs nine, strong, rounded, trichotomouswith the middle branch somewhat larger than the lateral ones, coarsely scaly, with interspace broader and filled with four to five equal or unequal scaly riblets, Inner border crenate. Height 64 millim. Length 62 millim. Depth 12.3 millim. This shell is also not unlike Pecten hastatus Sow. (Arnold, Tert. Quat. Pectens, pl. 42, fig. 1a), though different in finer sculptures.» MATAJIRO YOKOYAMA, 1929
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«Three well preserved specimens and several fragmentary ones were collected. This species has peculiar imbricated scales on the threads of the radial ribs and the same sculptures on threads in the interspaces. Radial ribs are 9 to 10 in number and are nearly equal to the interspaces in breadth. The anterior auricle is slightly larger than the posterior; the both are triangular in shape and similarly ornamented with a few radial threads and fine concentric lines. The byssal notch is shallow. This species is unique in having a posteriorly contorted shell which is higher than long.
This species is distinguished from Gloripallium izurensis which was described by Masuda (1958) from the Miocene Kokozura Formation of this coalfield by its greater number of radial ribs and the imbricated scales. The species has hitherto thought to be restricted its occurrence to the Miocene formations of the Japan Sea side and coeval formations of northern Honshu (Masuda, 1958, 1962). This may be the first record of this species in Pliocene rocks.» O'HARA, S. & N. NEMOTO. 1988. Pectinids from the Taga Group of the Joban Coalfield. Saito Ho-on Kai Special Publication, Professor Tamio Kotaka Commemorative Volume: 481-496, pls. 1-4. [p. 489]
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Gloripallium crassivenium (Yokoyama, 1929); S. O'Hara & N. Nemoto, 1988, Pectinids from the Taga Group of the Joban Coalfield, plate 1, figure 2.
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«Remarks:— When this species is badly water-worn, the characteristic surface sculpture becomes obliterated, so that it sometimes resembles Patinopecten kagamianus moniwaensis Masuda. However, it differs from kagamianus moniwaensis by the posteriorly contorted shell, possession of several intercalary threads and the auricles in the right valve, and in the left valve by the radial ribs which are nearly equal to the interspaces in breadth.
The imbrication of the scales on the radial ribs is so characteristic and so conspicuous that the external casts sometimes show the characteristic features. However, sometimes such features are not observed, and when only internal casts are faintly preserved or obliterated, they may be misjudged for a different species. Cryptopecten oyamadaensis was described by Hirayama (1954) based upon a single plaster-cast of the right valve from the Miocene Kobana formation, Tochigi Prefecture. However, by the re-examination of the type specimen (TKD, Reg. No. 10112) preserved in the Institute of Geology and Mineralogy, Faculty of Science, Tokyo University of Education, the writer considers it to be a synonym of crassivenium. Type locality, Geological formation and Age: — Road-side cliff at Iwaya, about 750 m. west of Nanao station, Nanao City, Ishikawa Prefecture (Lat. 37º01'03"N., Long. 136º57'04"E.). Nanao formation. Early Miocene. Distribution:— Nanao and Najimi formations, Ishikawa Prefecture; Iori formation, Toyama Prefecture; Kobana and Ogane formations, Tochigi Prefecture; Urushikubo formation, Fukushima Prefecture; Hatatate, Tsunaki, Aoso, Nanakita, Utsuno and Kuzumine formations, Miyagi Prefecture; Koidegawa, Maekawa, Kotsunagizawa and Suzukamogawa formations, Iwate Prefecture; Uncertain in Shimane Prefecture:, Early to Middle Miocene in age. Occurrence:— Common in the very fine-grained sandstone of the Suzukamogawa formation; rare in the calcareous medium-grained sandstone of the Nanao formation; few in the fine-grained sandstone of the Najimi formation; few in the fine-grained sandstone of the Hatatate formation; few in the very fine-grained sandstone of the Aoso formation; rare in the fine-grained sandstone of the Kotsunagizawa formation; common in the very finegrained sandstone of the Suzukamogawa formation.» MASUDA, K. 1962. Tertiary Pectinidae of Japan. Science Reports of the Tohoku University [2nd. Series - Geology], 33 (2): 117-238. [p. 197, 198]
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Gloripallium crassivenium (Yokoyama); K. Masuda, 1958, On the Miocene Pectinidae from the Environs of Sendai; part 11, On Pecten (Chlamys) crassivenius Yokoyama and its related species, plate 32, figures 1-3.
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«The Gloripallium was established by T. Iredale (1939, pp. 346, 357) for scallops having "Shell medium, equivalve, regular, ribs few, stout and very scaly, ears unqual, shell thick". The type spcies is designated as Ostrea pallium Linne, whose type locality is stated to be Amboina. The reference of M. Yokoyama's crassivenius to this genus may hold some doubts, but seeing that the shell is quite thick, with few ribs which are both stout and scaly, it appears that usage of the name for the Japanese Miocene fossil is acceptable. This species is a member of the tropical Miocene molluscan fauna of Japan.
In the present collection is found a well preserved right valve belonging to crassivenius as originally described by M. Yokoyama from the early Miocene Nanao formation developed in the environs of Nanao City, Noto Peninsula, Ishikawa Prefecture. At the time of description of his new species, M. Yokoyama gave no type locality but merely mentioned that the fossils were collected from five localities, namely, Kokubu, Hosoguchi, Iwaya, Tsumugi and Osugi-zaki. These localities are all within the distribution of the Nanao formation. However, K. Hatai and S. Nisiyama (1952, p. 109) designate the type locality as "Cliff at Iwaya, about 500m SW of Nanao-city", where this species occurs. As known at present, this species of M. Yokoyama is characteristic in the early Miocene of Japan and generally occurs in association with tropical to subtropical mollusca. It has not been found in definitely accepted late Miocene deposits and the peculiar complex sculpture as seen in the present specimen is a typical features of early Miocene scallops in Japan.» HIRAYAMA, K. 1954. Miocene Mollusca from the Arakawa Group, Tochigi Prefecture, Japan. (Part 1). Science Reports of the TokyoKyoiku Daigaku [Section C -Geology, Mineralogy and Geography], 3 (18): 43-75, pls. 3-5. [p. 52, 53]
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Gloripallium crassivenium (Yokoyama), 1929; K. Hirayama, 1954, Miocene Mollusca from the Arakawa Group, plate 3, figures 11, 12, 18.
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