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Volume 1988 (1988)
- Issue 152 Pages 603-
- Issue 151 Pages 501-
- Issue 150 Pages 435-
- Issue 149 Pages 361-
Volume 1988, Issue 151
Displaying 1-6 of 6 articles from this issue
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TATSUAKI KIMURA, TAMIKO OHANA, MASANORI TSUJII1988 Volume 1988 Issue 151 Pages 501-522
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSThis is the last (8th) of our serial papers. It deals with the supplementary description of newly obtained fossil plants and gives concluding remarks on the Early Jurassic plants in Japan. Based on the floristic composition, we recognized the Kuruma-type and Nishinakayama-type floras in late Early Jurassic time in Japan. The Nishinakayama-type flora is unique and exotic and there is no comparable flora in Eurasia. The Kuruma-type flora in Japan is similar in the floristic composition to coeval or nearly coeval floras in South China. In addition, we briefly reviewed Early Jurassic floras in Eurasia from a paleophytogeographical point of view. The taxa described in this paper are Gleichenites? sp. A, Phlebopteris sp. A, Dictyophyllum kotakiense Kimura et Tsujii, Sphenopteris sp. H, Ptilophyllum shinadaniense Kimura et Tsujii, P. sp. cf. P. hsiangshanense Wu, P. sp. A, Pterophyllum? sp., Pseudoctenis nipponica Kimura et Tsujii and Nilssonia sp. B from the Kuruma Group, and Sphenopteris sp. G, Otozamites sp. C and Pseudoctenis? sp. from the Nishinakayama Formation.View full abstractDownload PDF (3811K) -
KATSUO SASHIDA, KEIJI TONISHI1988 Volume 1988 Issue 151 Pages 523-542
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSWell-preserved upper Permian radiolarians were recovered abundantly from a chert block embedded in the Unazawa Formation distributed in Kashiwara, Itsukaichi Town, Tokyo Prefecture, central Japan. A part of this radiolarian fauna including the Families Entactiniidae, Palaeoactinomiidae, Palaeoscenidiidae and Phacodiscidae and the Superfamily Latentifistulidea has already been described by the present authors. This study is an addition to the continuing investigation of this fauna and several newly discriminated genera and species of Entactiniidae, Tormentidae, Albaillellidae and Spumellaria Incertae sedis are described. Among them, two genera Uberinterna and Triplanospongos and ten species are proposed as new to science. This paper also attempts to compare the present radiolarian fauna with that of the Ultra-Tamba Belt of Southwest Japan and of the Delaware Basin of West Texas.View full abstractDownload PDF (3094K) -
RIE HORI1988 Volume 1988 Issue 151 Pages 543-563
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSFour radiolarian species, including two new species, of the family Syringocapsidae Foreman are described from the lowest Jurassic bedded cherts of the Inuyama area, central Japan. These species belonging to the genera Katroma, Syringocapsa and Gigi are representatives of the Parahsuum simplum Assemblage, one of the important early Jurassic radiolarian assemblages established in Southwest Japan. On the basis of morphology and biostratigraphic distribution, both genera Gigi and Katroma are regarded as descendants of the genus Syringocapsa. The species of Katroma in the Lower Jurassic are biostratigraphic marker taxa because of their short range and world-wide occurrences. Therefore, the upper part of the Parahsuum simplum Assemblage-zone with species of Katroma is probably assignable to upper Sinemurian to upper Pliensbachian.View full abstractDownload PDF (4376K) -
ITARU HAYAMI1988 Volume 1988 Issue 151 Pages 564-569
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA Monotis-like thin-shelled bivalve occurs from the Fontanelliceras fontanellense Zone (upper Pliensbachian) of the Nishinakayama Formation in west Japan. This bivalve, though formally undescribed, has been noticed by some foreign investigators from the standpoint of biogeography, because such a bivalve often shows episodic occurrence and wide geographic distribution. Recently, I observed some well-preserved materials of this species stored in the Hiroshima University and the Mine City Museum of History and Folk Custom, reaching a conclusion that it belongs to Posidonotis dainellii from the nearly contemporaneous dark shales of Italy and Greece. The obliquely truncated auricles and radial costae of three orders, which may be diagnostic of this species, are well recognized in the Japanese specimens. The wide geographic distribution is probably related to the pseudoplanktonic mode of life. This bivalve, as well as some ammonoids in the same fossil zone, is regarded as a noticeable element indicating a marine faunal connection with the Mediterranean region at that time.View full abstractDownload PDF (1553K) -
TATSURO MATSUMOTO, KEISAKU TANAKA1988 Volume 1988 Issue 151 Pages 570-581
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA specimen obtained by K. T. from his Member Tc (=IIc of T. M.), i.e. the middle part of the Mikasa Formation in the Ikushumbets Valley, was labelled as Inoceramus cf. etheridgei Woods and is hold in the Geological Museum of the Geological Survey of Japan. This is restudied by us together with other relevant specimens from the Upper Cenomanian strata in the Ikushumbets and Oyubari areas, central Hokkaido. They represent a new species which is allied to I. scalprum Bohn (=I. etheridgei Woods, currently included in I. virgatus Schluter as a variety or a subsp. by some authors), but characterized by regular concentric ribs in addition to fine concentric lirae. This species resembles I. atlanticus (Heinz) but is distinguished by a dissimilar outline of the shell caused by its anteriorly concave growth axis instead of the nearly straight to weakly convex one of that species. We interpret that this species may have evolved from the scalprum-like form of the variable species I. virgatus, with development of distinct ribs. There seems to be a reduction in size at higher levels than the type locality. Some of the specimens previously reported under I. tenuistriatus Nagao et Matsumoto from the Cenomanian strata in various regions of the world may be preferably transferred to this species.View full abstractDownload PDF (2968K) -
MASAYUKI NODA1988 Volume 1988 Issue 151 Pages 582-600
Published: October 31, 1988
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSIn the original description Inoceramus tenuistriatus Nagao et Matsumoto, 1939 was well defined, but the species has not been always understood correctly by some foreign researchers. In this paper I. tenuistriatus is biometrically restudied on a population sample from the type locality. The statistics are taken for eight characters on 30 left and 27 right valves. A revised description of I. tenuistriatus is given, including the result of the biometric examination. I discuss the relationship of the redefined I. tenuistriatus with the so-called "I. (I.) tenuistriatus" (with or without query) from the Cenomanian of Euramerica and the Pacific Coast of the USSR. It has been confirmed that the so-called "I. (I.) tenuistriatus" should be morphologically discriminated from the sample specimens of the type locality. In connection with this, I agree with Matsumoto and Tanaka (1988) in their suggestion that the so-called "I. (I.) tenuistriatus" may be identical with I. nodai Matsumoto et Tanaka, 1988 from the Upper Cenomanian of Hokkaido. The stratigraphic unit of the type locality of I. tenuistriatus is clearly assigned to the Upper Turonian on the evidence of associated species. Besides, "I. tenuistriatus" has been reported to occur at several horizons other than the Upper Turonian in various areas of Japan, the true range of this species is yet to be worked out further.View full abstractDownload PDF (4356K)
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