Bulletin of the Mizunami Fossil Museum
Online ISSN : 2435-0931
Print ISSN : 0385-0900
Volume 49
Displaying 1-6 of 6 articles from this issue
  • Carrie E. Schweitzer, Rodney M. Feldmann, Raelyn P. Eckert
    2022 Volume 49 Pages 1-16
    Published: 2022
    Released on J-STAGE: March 01, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    Only two genera are currently referred to Asthenognathinae, one extinct, Globihexapus Schweitzer and Feldmann, 2001, and the other ranging from Oligocene to Holocene, Asthenognathus Stimpson, 1858. Asthenognathinae is currently recognized as a member of Varunidae. New specimens of Globihexapus from the Miocene Astoria Formation, Newport, Oregon, are more complete than the original material and permit more detailed description of the type species. Globihexapus shares many features with Asthenognathus and is confirmed as member of that subfamily. A detailed diagnosis for the Asthenognathinae is provided, possibly for the first time. Latitudinal range for members of Asthenognathinae have broadened in the Holocene to include tropical occurrences, whereas southern hemisphere occurrences are not recorded today. No ev-idence of commensal lifestyle is reported for fossil occurrences.
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  • Rodney M. Feldmann, Carrie E. Schweitzer
    2022 Volume 49 Pages 17-24
    Published: 2022
    Released on J-STAGE: March 01, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    The type material of Linuparus canadensis (Whiteaves, 1885a) and Linuparus vancouverensis (Whiteaves, 1895) from British Columbia, Canada, are re-illustrated. Key features not originally mentioned are indicated. Many eastern North American occurrences previously referred to L. canadensis should be placed within L. keyesi Kornecki et al., 2017. Thus, the geographic range of L. canadensis is modified and restricted to Western and Central North America.
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  • Susumu Kato, Chikara Hiramatsu
    2022 Volume 49 Pages 25-35
    Published: 2022
    Released on J-STAGE: March 01, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    The boundary between the Kazusa Group and the Miocene sequence in the Sayama Yamato well, which is unconformable, ranges from 920 m to 940 m in depth based on lithofacies of cuttings. The Miocene sequence has yielded calcareous nannofossil and fossil diatom assemblages, which are assigned to CN5a and NPD5A zones respectively, and correlates with the late Middle Miocene sequence, the lower part of the Negishi Formation, the Tokigawa Group, in the Iwadono Hills. The silica mineral phase boundary of opal-A and opal-CT is considered to be between 1,200 m and 1,220 m in depth of the well based on the occurrence of fossil diatoms.
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  • Stephen K. Donovan, Eduard, T. M. Messemaeckers, John W. M. Jagt
    2022 Volume 49 Pages 37-44
    Published: May 13, 2022
    Released on J-STAGE: May 13, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    The Palaeozoic palaeontological diversity of glacio-fluvial erratics in the Lower Rhine (Niederrhein) district of the federal state of Nordrhein-Westfalen (Germany), close to the Dutch/German border, may be locally varied, but can be limited. Nominal crinoids are almost unknown. Most sea lily material is in the form of generally indeterminate external moulds of pluricolumnals and rare thecal remains in various Lower and Middle Devonian sandstone facies types that are often lumped as ‘Spiriferen-Sandstein’. An incomplete theca from the Siemes Sand- and Kiesbaggerei at Wemb, close to Weeze and Kevelaer, is here tentatively assigned to the monobathrid camerate genus Eucalyptocrinites. The vase-shaped theca has crystal apple-type preservation; some brachial series and large interbrachial plates are apparent; and a central broad canal is rounded in outline. This specimen was probably derived by glacial and/or fluvial action from the east or, more likely, north. Although left in open nomenclature, the specimen is close to Eucalyptocrinites granulatus (Lewis) from the Silurian (Wenlock) of Gotland.
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  • Stephen K. Donovan
    2022 Volume 49 Pages 45-49
    Published: May 13, 2022
    Released on J-STAGE: May 13, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    Charles Taylor Trechmann (1884–1964) was an independently wealthy researcher on the fossil faunas of north-east England and the Antilles. He formulated his theory of mountain uplift in response to the idea of a basal complex beneath the Antilles, proposed by Charles Alfred Matley (1866–1947). Trechmann’s ideas on tectonics were promulgated mainly in a series of four monographs that he published privately. In 1953 Trechmann gave a talk on mountain uplift to the British Association for the Advancement of Science, but was refused publication in their journal ‘Advancement of Science’. Trechmann implied that the rejection of this short note led to him writing the last and longest of his monographs. This explanation was likely disingenuous. Trechmann had difficulties in publishing his tectonic theory in recognised research journals. Most likely, he wanted to publish in ‘Advancement of Science’ to reach a wider audience for the mountain uplift theory. His last and longest monograph was probably always planned as a ‘last hurrah’ as a publishing scientist; Trechmann published little subsequently.
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  • Yusuke Ando
    2022 Volume 49 Pages 51-58
    Published: May 13, 2022
    Released on J-STAGE: May 13, 2022
    RESEARCH REPORT / TECHNICAL REPORT OPEN ACCESS
    Very small, stereotyped drill holes are found in 15 shells of Kotorapecten egregius (Itoigawa), collected from the lower Miocene Akeyo Formation (ca. 18 Ma) of the Mizunami Group in Mizunami City, Gifu, central Japan based upon the examination of the collection of Mizunami Fossil Museum. These drill holes can be assigned to the ichnotaxon Oichnus ovalis Bromley, attributed to predation by octopods. These examples are the oldest ambiguous fossil records of the octopod-predatory drill holes found in Japan.
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