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Volume 1994 (1994)
- Issue 176 Pages 591-
- Issue 175 Pages 497-
- Issue 174 Pages 411-
- Issue 173 Pages 329-
Volume 1994, Issue 174
Displaying 1-5 of 5 articles from this issue
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YUKIO YANAGISAWA1994 Volume 1994 Issue 174 Pages 411-425
Published: June 30, 1994
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA new fossil diatom species Mediaria magna Yanagisawa sp. nov. is described from the lower Middle Miocene Oidawara Formation in Mizunami area, Gifu Prefecture, Japan. Morphologic investigation by light and scanning electron microscopes has revealed that Mediaria magna is distinct from Mediaria splendida f. splendida and M. splendida f. tenera by its unique characteristics. M. magna is of great value in Neogene diatom biostratigraphy because it is easily identifiable even when fragmented and also because it is very short-lived, being restricted to the lower part of the early Middle Miocene Denticulopsis lauta Zone (NPD 4A) of the Neogene North Pacific diatom zone (Akiba, 1986). Scanning electron microscopy reveals the presence of a raphe in the genus Mediaria for the first time. The genus has a raphe of simple slit without fibulae and therefore it cannot be placed in the order Bacillariales Hendey. It is morphologically similar to some genera in the family Catenulaceae Mereschkowsky in the order Thalassiophysales Mann.View full abstractDownload PDF (3836K) -
YASUFUMI IRYU, SHINYA MATSUDA1994 Volume 1994 Issue 174 Pages 426-448
Published: June 30, 1994
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSTaxonomic studies of the "Neogoniolithon fosliei complex" are conducted on the basis of the Recent materials collected from reefs on Ishigaki-jima (Ishigaki Island), the Ryukyu Islands, southwestern Japan. Detailed morphological and anatomical examination reveals that nonarticulated coralline algae comprising the complex are classified into three species : N. fosliei, N. tenuicrustaceum sp. nov., and Neogoniolithon sp. A. The arrangement of bi-/tetrasporangia in the conceptacle chamber (across the floor or periphery only) or the presence or absence of the central columella is proved to be of potential taxonomic signiflcance for distinguishing Neogoniolithon from Spongites.View full abstractDownload PDF (7976K) -
AKIHIRO KANO, DONG JIN LEE, DUCK KEUN CHOI, CHAN MIN YOO1994 Volume 1994 Issue 174 Pages 449-457
Published: June 30, 1994
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSThe Ordovician stromatoporoid Labechiella regularis (Yabe and Sugiyama) has been recovered from the shallow ramp facies of the Yeongheung Formation (Llanvirnian) of the Ogcheon Fold Belt in southern Korea. The skeletal characteristics of this species have been altered by diagenesis. It represents the first discovery of a stromatoporoid from the southern part of the Korean peninsula. This Middle Ordovician stromatoporoid occurrence extends the geographical range of the species, previously reported from other parts of Asia.View full abstractDownload PDF (1889K) -
SATOSHI FUNAKAWA1994 Volume 1994 Issue 174 Pages 458-483
Published: June 30, 1994
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSWell-preserved radiolarians are abundant in diatomaceous siltstones of the Taiki Formation (Upper Miocene) in the Toyokoro Hills region, and the Chokubetsu, Atsunai and Shiranuka Formations (Middle Miocene to Lower Pliocene) in the Atsunai Coast region, eastern Hokkaido, Japan. Fifteen samples are studied from five routes ; Oikamanai River, Yudou River, Noyaushi River, Ishii-zawa River and Atsunai Coast routes. Plagiacanthidae species are a principle component of these assemblages. Seven genera of Lophophaeninae (including two new genera and six new species), two of Clathromitrinae and one of Sethoperinae are described. Three groups of Plagiacanthidae having characteristic internal skeletal structures are recognized.·Group 1 : The first segment is distinguished from the second segment by only AL.·Group 2 : The first segment is distinguished from the second segment by AL and VL (instead of AL and LL when V is lacking).·Group 3 : The first segment is distinguished from the second segment by DL and VL, or AL-AL, AL and VL, or DL and LL. All genera of groups 1 and 2 are included in Lophophaeninae, while two genera of group 3 are in Clathromitrinae, one is in Sethoperinae and one is in Lophophaeninae.View full abstractDownload PDF (6155K) -
SUMIO SAKAGAMI, YOSHIHIRO MIZUNO1994 Volume 1994 Issue 174 Pages 484-495
Published: June 30, 1994
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSFusulinaceans and conodonts indicating the Atokan (early Middle Pennsylvanian) of North America are now discovered for the first time from the lower part of the Copacabana Group which was previously considered Virgilian (latest Pennsylvanian) to Leonardian (early Middle Permian) in age. The fusulinaceans, Profusulinella sp. indet. and Profusulinella munda Thompson, and conodonts, Diplognathodus orphanus (Merrill), Idiognathodus delicatus Gunnell and Neognathodus medadultimus Merrill are described and illustrated. These faunules may be included in the Midcontinent-Andean Province.View full abstractDownload PDF (1852K)
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