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The cephalic skeletal structure of Jurassic “Eucyrtidium” (Radiolaria)

Published online by Cambridge University Press:  14 July 2015

Atsushi Takemura
Affiliation:
Department of Geology and Mineralogy, Faculty of Science, Kyoto University, Kyoto 606, Japan
Kojiro Nakaseko
Affiliation:
Institute of Geological Sciences, College of General Education, Osaka University, Toyonaka 560, Japan

Abstract

Almost all nassellarians possess some skeletons, comprised of cephalic skeletal elements, at the base of their cephalis. Observations using the scanning electron microscope (SEM) have been made on the internal structures of Jurassic “Eucyrtidium” from manganese carbonate ore deposits in the Mino Terrane, central Japan. Jurassic “Eucyrtidium” possesses only a median bar and apical spine as cephalic skeletal elements. Because this structure is quite different from that of Cenozoic Eucyrtidium, which possess MB, A, V, L, l, and D, a new genus, Monosera, is proposed for the Jurassic forms. One new species, Monosera gujoensis, is described.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

De Wever, P. 1982. Nassellaria (Radiolaires Polycystines) du Lias de Turquie. Revue de Micropaléontologie, 24:189232.Google Scholar
Dumitrica, P. 1970. Cryptocephalic and cryptothoracic Nassellaria in some Mesozoic deposits of Romania. Revue Roumaine de Géologie, Géophysique et Géographie, Série de Géologie, 14:45124.Google Scholar
Ehrenberg, C. G. 1838. Über die Bildung der Kreidefelsen und des Kreidemergels durch unsichtbare Organismen. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1838, p. 59147.Google Scholar
Ehrenberg, C. G. 1875. Fortsetzung der mikrogeologischen Studien als Gesammt Uebersicht der mikroskopischen Paläontologie gleichartig analysirter Gebirgsarten der Erde, mit specieller Rücksicht auf den Polycystinen-Mergel von Barbados. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1875, p. 1226.Google Scholar
Empson-Morin, K. 1981. Campanian Radiolaria from DSDP Site 313, Mid-Pacific Mountains. Micropaleontology, 27:249292.CrossRefGoogle Scholar
Hattori, I. 1982. The Mesozoic evolution of the Mino Terrane, central Japan: a geologic and paleomagnetic synthesis. Tectonophysics, 85:313340.CrossRefGoogle Scholar
Ichikawa, K. and Yao, A. 1976. Two new genera of Mesozoic cyrtoid radiolarians from Japan, p. 110117. In Takayanagi, Y. and Saito, T. (eds.), Progress in Micropaleontology. Micropaleontology Press.Google Scholar
Kojima, S. 1984. Paleozoic-Mesozoic strata in the Takayama area, Gifu Prefecture, central Japan: their stratigraphy and structure. Journal of the Geological Society of Japan, 90:175190 (in Japanese with English abstract).Google Scholar
Müller, J. 1858. Über die Thalassicollen, Polycystinen und Acanthometren des Mittelmeeres. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1858, p. 162.Google Scholar
Nakaseko, K. and Sugano, K. 1973. Neogene radiolarian zonation in Japan. The Memoirs of the Geological Society of Japan, 8:2333 (in Japanese with English abstract).Google Scholar
Nishimura, A. and Yamauchi, M. 1984. Radiolarians from the Nankai Trough in the Northwest Pacific. News of Osaka Micropaleontologists, Special Volume 6, 148 p.Google Scholar
Oba, T. 1967. Planktonic foraminifera from the deep-sea cores of the Indian Ocean. Science Reports of Tohoku University, Second series, Geology, 38:193219.Google Scholar
Petrushevskaya, M. G. 1962. Znachenie rosta skeleta radiolyarii dlya sistematiki. Zoologicheskii Zhurnal, 41:331341.Google Scholar
Petrushevskaya, M. G. 1971. On the natural system of polycystine Radiolaria (Class Sarcodina), p. 981992. In Proceedings of Second Planktonic Conference, Roma, 1970 Edizioni Tecnoscienza, Rome.Google Scholar
Riedel, W. R. 1967. Protozoa (Subclass Radiolaria), p. 291298. In Harland, W. B. et al. (eds.), The Fossil Record. Geological Society of London.Google Scholar
Riedel, W. R. 1971. Systematic classification of polycystine Radiolaria, p. 649661. In Funnell, B. M. and Riedel, W. R. (eds.), The Micropaleontology of Oceans. Cambridge University Press.Google Scholar
Riedel, W. R. and Sanfilippo, A. 1974. Radiolaria from the southern Indian Ocean, DSDP Leg 26. Initial Reports of Deep Sea Drilling Project, 26:771813.Google Scholar
Riedel, W. R. and Sanfilippo, A. 1978. Stratigraphy and evolution of tropical Cenozoic radiolarians. Micropaleontology, 24:6196.CrossRefGoogle Scholar
Sugano, K. and Nakaseko, K. 1971. On the assemblage of fossil radiolaria in the neighbourhood of Kitakanbara Plain, Niigata Prefecture, Japan—studies of fossil radiolarian stratigraphy of the Neogene Formation, Niigata Prefecture, Japan (Part 3). Memoirs of Osaka Kyoiku University, series 3, 20:6379 (in Japanese with English abstract).Google Scholar
Takemura, A. and Hirota, K. 1983. Radiolarians from dolomitic nodules of the Tsurushi Formation, Sado Island, Japan. News of Osaka Micropaleontologists, 10:2938 (in Japanese with English abstract).Google Scholar
Takemura, A. and Nakaseko, K. 1982a. Two new Jurassic genera of Family Palaeoscenidiidae (Radiolaria). Transactions and Proceedings of the Palaeontological Society of Japan, new series, 128:452464.Google Scholar
Takemura, A. and Nakaseko, K. 1982b. On cephalic structures of Jurassic Nassellaria, p. 183194. In JRS 81 Osaka, Proceedings of the First Japanese Radiolarian Symposium, News of Osaka Micropaleontologists, Special Volume 5 (in Japanese with English abstract).Google Scholar
Takemura, A. and Nakaseko, K. 1983. Perseus, a new genus of Jurassic Palaeoscenidiidae and the phylogeny of subfamily Hilarisirecinae. Memoirs of the Faculty of Science, Kyoto University, Series of Geology and Mineralogy, 49:111118.Google Scholar
Takemura, A. and Yamauchi, M. 1984. The cephalic structure of Cornutella (Radiolaria) and its phylogeny. News of Osaka Micropaleontologists, 12:3339 (in Japanese with English abstract).Google Scholar
Wakita, K. and Okamura, Y. 1982. Mesozoic sedimentary rocks containing allochthonous blocks, Gujo-hachiman, Gifu Prefecture, central Japan. Bulletin of Geological Survey of Japan, 33:161185 (in Japanese with English abstract).Google Scholar
Yao, A. 1972. Radiolarian fauna from the Mino belt in the northern part of the Inuyama area, central Japan. Part I: spongosaturnalids. Journal of Geoscience, Osaka City University, 15:2164.Google Scholar
Yao, A. 1979. Radiolarian fauna from the Mino belt in the northern part of the Inuyama area, central Japan. Part II: Nassellaria 1. Journal of Geoscience, Osaka City University, 22:2172.Google Scholar
Yao, A., Matsuoka, A. and Nakatani, T. 1982. Triassic and Jurassic radiolarian assemblages in Southwest Japan, p. 2743. In JRS 81 Osaka, Proceedings of the First Japanese Radiolarian Symposium, News of Osaka Micropaleontologists, Special Volume 5 (in Japanese with English abstract).Google Scholar