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Volume 1987 (1987)
- Issue 148 Pages 197-
- Issue 147 Pages 91-
- Issue 146 Pages 35-
- Issue 145 Pages 1-
Volume 1987, Issue 147
Displaying 1-7 of 7 articles from this issue
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MASAYUKI TASHIRO1987 Volume 1987 Issue 147 Pages 91-108
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSIn this paper 4 species of Eomiodon and 8 species and 2 subspecies of Costocyrena (including Costocyrena ohnishii, sp. nov., Costocyrena hojiensis, sp. nov. and Costocyrena otsukai obsoleta, subsp. nov.) belonging to the Family Neomiodontidae are described from the Cretaceous at various localities in southwest Japan. Geographic distribution of Eomiodon and Costocyrena species seems to change through the Cretaceous time in southwest Japan. In the Lower Cretaceous, Eomiodon species restrictedly occur from the southern side of Kurosegawa Tectonic Belt, while all Costocyrena species are known from the northern side of that belt, Northern Chichibu Belt. In the Upper Cretaceous, the geographic distribution of the two genera becomes overlap, and they occur together even at the same localities especially in central Kyushu. This may not mean habitat change of these bivalves, but seems to support the hypothesis of the Early Cretaceous movement of a large lateral fault in the Chichibu Belt.View full abstractDownload PDF (3041K) -
TEIICHI KOBAYASHI, TAKASHI HAMADA1987 Volume 1987 Issue 147 Pages 109-116
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSSeven species of trilobites including two new genera and three new species are here described from Mt. Yokokura. Metaleiolichas and Paraleiolichas are two new genera, each represented by a new species. A new species of Japonoscutellum is added to them. Two pygidia are new to the two known species and one pygidium is so well preserved that it is capable of emending the existing description. Finally, a free cheek is a new find of a species for its locality. Thus the previous knowledge of the Yokokura-yama fauna is well advanced with all of these specimens.View full abstractDownload PDF (2101K) -
SHUJI NIKO1987 Volume 1987 Issue 147 Pages 117-130
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSThe lower part of the Ichinotani Formation at Fukuji, Gifu Prefecture, central Japan contains a very rich assemblage of foraminifers. Eostaffella (primitive fusulinacea) is described here to provide a basis for the precise biostratigraphic subdivision and age-determination of the lower Ichinotani Formation. The eostaffelloids consist of eight species including three new species, i. e., Eostaffella excavata, E. igoi and E. subulba. This assemblage permits recognition of Igo's Eostaffella kanmerai zone ranging from latest Visean to early Serpukhovian (Namurian A) in age.View full abstractDownload PDF (2345K) -
TEIICHI KOBAYASHI, TAKASHI HAMADA1987 Volume 1987 Issue 147 Pages 131-145
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA new collection from Hitoegane adjacently north of Fukuji, Gifu Prefecture contains more than nine species of trilobites in the Scutelluidae, Illaenidae (?), Proetidae, Cheiruridae and Encrinuridae, including four new species, namely Kosovopeltis hidensis, Proetus (Coniproetus) tenuiceps, P. (Coniproetus?) subconicus and Cheirurus hitoeganensis. This faunule is late or middle Ludlovian in age and shows affinities to the East Australian fauna through the Yokokura-yama, Shikoku and the Bohemian fauna through the trilobites of the Mongolian geosyncline. Encrinurus cf. similis found at Hakubado, Fukui Prefecture is about the same age.View full abstractDownload PDF (4093K) -
TATSURO MATSUMOTO, AKITO ASAI, HIROMICHI HIRANO1987 Volume 1987 Issue 147 Pages 146-164
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSIn our recent acquisitions from the Obira and northerly adjoining Kotanbetsu areas and also from the Oyubari area of Hokkaido there are following three species, which are well known abroad but hitherto undescribed in Japan : (1) Inoceramus tenuis Mantell; This is fairly common in the lower and middle parts of the Cenomanian in the Obira and adjacent areas. Our forms are mostly smaller than but otherwise similar to the holotype from England. (2) Inoceramus gradilis Pergament; A fine example, with both valves preserved, was obtained from the Middle Cenomanian bed with Calycoceras sp. of newboldi group in the Kotanbetsu area. Ten other specimens came from Member Mh (upper part of the Cenomanian) of the Obira area. This species was originally reported from the Koryak Range of the USSR and its distribution is now extended to Hokkaido. (3) Inoceramus virgatus Schluter; This species is so variable that we include in it "I. scalprum Bohm" as a synonym, giving a revised diagnosis. Examples from Hokkaido occur in the middle to uppermost part of Member Mf of the Obira area, probably referable to the lower Middle Cenomanian; also in the Lower Cenomanian of the Oyubari area.View full abstractDownload PDF (6024K) -
KAZUSHIGE TANABE, YASUNARI SHIGETA1987 Volume 1987 Issue 147 Pages 165-179
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSComparative shell shape analysis of some Cretaceous ammonites has provided significant differences in the ontogenetic pattern and variation of geometric coiling parameters. The differences are especially conspicuous in the distance of venter from coiling axis (D), relative whorl thickness (S) and flank position (F), all of which are key factors for considering hydrodynamic efficiency of the shells. In every species, the ranges of variation of the geometric parameters tend to decrease with age. At the same growth stage, intraspecific variation of parameters S and D is largest in the heavily ornamented morphotypes (Acanthocerataceae) and heteromorphs (Scaphitaceae), imermediate in fine-ribbed platycones (Lytocerataceae), and smallest in the weakly ribbed, highly streamlined involute-compressed morphotypes (Hypophylloceras, Placenticeras and most Desmocerataceae). This evidence strongly suggests a wide variety of adaptive designs of the shells related to the mode of life of ammonites.View full abstractDownload PDF (1940K) -
KAZUYOSHI ENDO1987 Volume 1987 Issue 147 Pages 180-194
Published: October 30, 1987
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSJapanese Cenozoic laqueid brachiopods generally show two allometric trends. One is the ontogenetic increase in valve convexity versus valve length, and the other is the ontogenetic decrease in valve width versus valve length. To examine the causation of these morphologic changes, the general morphology, life habit, and allometric relationships of some metric characters were investigated in the Recent samples of Laqueus rubellus (Sowerby). The following are three explanations for the relative increase of shell convexity : 1) efficient secretion of shell material, 2) strengthening the shells, and 3) providing larger space for adult gonad. Among them, the third explanation seems most appropriate at least in L. rubellus, because of a diphasic allometric relationship between valve convexity and valve length : while valve convexity is positively allometric to valve length in adults, they are isometrically related in juveniles.View full abstractDownload PDF (1578K)
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