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Volume 1984 (1984)
- Issue 136 Pages 445-
- Issue 135 Pages 395-
- Issue 134 Pages 335-
- Issue 133 Pages 265-
Volume 1984, Issue 136
Displaying 1-4 of 4 articles from this issue
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KEISAKU TANAKA, MASAYUKI NODA, HITOSHI TANAKA1984 Volume 1984 Issue 136 Pages 445-454_1
Published: December 30, 1984
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSIn this paper four species of spatangoid echinoids are described which came from the Upper Formation of the Haidateyama Group in Oita Prefecture. They are three species of Heteraster, of which one is new, and one species assigned to Pseudowashitaster. For the description of a new species, material from the Lower Cretaceous Arida Formation in Wakayama Prefecture also is complementally dealt with here. Three of the echinoid species occur in common in the Lower Barremian of several areas in the Chichibu Terrane, Southwest Japan. Therefore, this combined with already reported ammonites strongly suggests an Early Barremian age for the Upper Formation of the Haidateyama Group.View full abstractDownload PDF (1348K) -
MASAYUKI NODA1984 Volume 1984 Issue 136 Pages 455-473
Published: December 30, 1984
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSIn this paper, Inoceramus incertus Jimbo, 1894 is restudied biometrically as well as taxonomically and biostratigraphically. At first normal distribution of various characters is evaluated for each sample from Pombets of Hokkaido by the method of chi-square test, and the specific diagnosis is revised. Then the extent of variation for selected characters are numerically shown. Finally the biostratigraphic significance of the species is discussed. The results obtained are as follows : (1) Inoceramus incertus Jimbo should be assigned to Mytiloides. Almost all the specimens of so-called I. incertus from Pombets are assigned to M. incertus which shows a considerable extent of variation in shell form and surface ornamentation. The extent of variation tends to expand in ascending the stratigraphic sequence. (2) A few specimens from loc. Ik2014 are distinctly outside the variation of M. incertus and should be called Mytiloides sp. aff. M. mytiloidiformis (Troger). (3) M. fiegei (Troger) from the Upper Turonian of various regions of the world is probably regarded as a junior synonym of M. incertus. Thus, M. incertus can be evaluated as one of the widespread indices of the Upper Turonian.View full abstractDownload PDF (2363K) -
ATSUSHI KANEKO1984 Volume 1984 Issue 136 Pages 474-491
Published: December 30, 1984
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSA trilobite fauna has been discovered from the Middle Devonian Nakazato Formation in the southern part of the Kitakami Mountains in northeastern Honshu, Japan. The fauna is composed of lichid, scutellid, dechenellid, calymenid, phacopid, dalmanitid and odontopleurid trilobites from the Higuchi-zawa and Ohmori-zawa, Hikoroichi-cho, Ofunato City, Iwate Prefecture. The purpose of the present paper is to give a description of the trilobites from the Higuchi-zawa locality of the fauna. A new lichid genus Nipponarges gen. nov. and its type-species Nipponarges mediosulcatus, gen. et sp. nov. and a new lichid species Acanthopyge (Acanthopyge) duplicispinata, sp. nov. are proposed in this part. Thysanopeltella paucispinosa (Okubo, 1951) and Dechenella (Dechenella) minima (Okubo, 1951), which had been previously considered to be reliable fossil evidences of the Eifelian in the Ohmori-zawa and of the Givetian in the Higuchi-zawa respectively, co-exist at the Higuchi-zawa locality. In the present state of knowledge it is only Thysanopeltella Kobayashi 1957 that can be used as an age indicator of this trilobite fauna. Therefore, the geological age of the fauna may be Eifelian.View full abstractDownload PDF (2243K) -
RITSUO NOMURA1984 Volume 1984 Issue 136 Pages 492-501
Published: December 30, 1984
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSFour species of Cassidulinidae, Globocassidulina biora (Crespin), Cassidulinoides porrectus (Heron-Allen and Earland), C. parvus (Earland) and Ehrenbergina glabra Heron-Allen and Earland, from the raised beaches and modern bottom sediments in the eastern part of Lutzow-Holm Bay, Antarctica are described and revised on the basis of ontogenetic and new anatomic information. The ontogenetic development of the aperture in G. biora is divided into the following three steps : I-shaped, L-shaped, and =-shaped, so that G. biora is morphologically similar to Globocassidulina subglobosa (Brady) and G. crassa rossensis Kennett in immature stages respectively. Uncoiled forms, such as C. porrectus and C. parvus, are also similar to G. subglobosa in globular immature stages.View full abstractDownload PDF (2212K)
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