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1 July 2018 Plant Fossils from the Arimine Formation (Oxfordian, Jurassic) of the Tetori Group in Arimine, Toyama Prefecture, Central Japan
Toshihiro Yamada
Author Affiliations +
Abstract

Ptilophyllum sp. and Zamites brevipennis are newly described from the middle Oxfordian Arimine Formation in the Arimine area, Toyama Prefecture, Central Japan. These two species characterize the vegetation of the Eurosinian paleophytogeographic province where a climate with dry season(s) prevailed. This finding, as well as the presence of a Kaizara Flora, suggests that Eurosinian-type vegetations continuously flourished during the late Bathonian to Oxfordian on the land of the Tetori Group. We also infer that Tetori-type floras first appeared during the Tithonian in the Tetori Group.

Introduction

The paleophytogeographic provinces were largely divided into the Siberian and Eurosinian provinces in Eastern Asia during the Middle Jurassic to Early Cretaceous period (Vakhrameev, 1987, 1991). The Siberian province, located north of the Eurosinian province, was characterized by a warm-temperate climate. The vegetation of the Siberian province was characterized by broadleaved gymnosperms (e.g. Podozamites, Dictyozamites and Neozamites), Ginkgoales, Czekanowskiales, and diverse pteridophytes such as Dicksoniaceae and Osmundaceae (Vakhrameev, 1987, 1991). In contrast, the Eurosinian province lay within a subtropical to tropical belt in which a seasonally dry climate mainly prevailed after the Bathonian (Vakhrameev, 1987, 1991). In the Eurosinian province, microphyllous gymnosperms flourished, such as Otozamites and Ptilophyllum (Bennettitales), Brachyphyllum, Pagiophyllum, and cheirolepidiaceous genera (Coniferales) (Vakhrameev, 1987, 1991). The genus Zamites (Bennettitales) was also unique to the Eurosinian province (Vakhrameev, 1987, 1991). The boundary between the two provinces was placed at the line connecting the middle part of Sikhote-alin and the southern margin of the Baikal region at the beginning of the Oxfordian (Vakhrameev, 1987, 1991), while its position fluctuated during the Middle to Late Jurassic (Vakhrameev, 1987, 1991).

Such a phytogeographic scheme is generally applicable in Japan, where Siberian-type and Eurosinian-type vegetations are represented by Tetori-type and Ryosekitype floras, respectively (Kimura, 1987, 1988, 2000). Tetori-type floras have been reported only from the Tetori Group distributed in the Hokushinetsu District (Figure 1), in the Inner Zone of Central Japan (Kimura, 1958, 1975, 1987, 1988; Kimura and Sekido, 1976; Yabe et al., 2003), whereas Ryoseki-type floras have been reported from Northeast Japan and the Outer Zone of Southwest Japan (Kimura, 1987, 1988, 2000; Kimura and Ohana, 1988a, b, 1989; Kimura et al., 1991). It has long been recognized that Tetori-type floras continuously flourished in the Tetori Group during the Middle Jurassic to the Early Cretaceous (Kimura, 1987, 1988, 2000). However, this interpretation is markedly different from observations in Eurasia of Eurosinian-type vegetation in the far northern region compared to the Tetori Group area during the Middle to Late Jurassic (Vakhrameev, 1987, 1991). Vakhrameev (1991) attempted to reconcile this discrepancy by hypothesizing that the Late Jurassic Tetori-type flora represents a vegetation type of the continental margin with high precipitation.

The “Kuzuryu Flora” (Kimura, 1958) constitutes the basis for the “Middle to Late Jurassic Tetori-type flora”, and was proposed to comprise plant fossil assemblages from Hakogase, Kowashimizu, Mochiana, Ushimaru, and Wakogo localities (Figure 1), where the Bajocian to Oxfordian “Kuzuryu Subgroup” of the Tetori Group outcrops (Kimura, 1958; Maeda, 1961a). However, stratigraphic revisions of these plant-bearing sediments have been conducted in the last 15 years based on ammonoids (Sato et al., 2003, 2008; Sato and Yamada, 2005) and radiometric dating (Kusuhashi et al., 2006; Kawagoe et al., 2012). As a result, it is now accepted that the sediments are younger than Tithonian (Yamada and Uemura, 2008; Figure 2).

Figure 1.

Distribution of the Tetori Group (shaded) based on Maeda (1961b) and the fossil locality (AR0021) in the Arimine area. Numbers indicate fossil localities of the “Kuzuryu Flora” and the Kaizara Flora; 1, Ushimaru; 2, Hakogase and Mochiana; 3, Kaizara; 4, Shimoyama; 5, Wakogo; 6, Kowashimizu. Abbreviations: As, Asuwagawa River; Jg, Joganjigawa River; Jz, Jinzugawa River; Kz, Kuzuryugawa River; Sg, Shogawa River; Td, Tedorigawa River.

f01_203.jpg

In addition, we reported a late Bathonian to Callovian Kaizara Flora from the Kaizara Formation in the Kuzuryu/Itoshiro area, Fukui Prefecture (Figures 1, 2), whose age was confirmed by ammonoids occurring along with the plants (Yamada and Uemura, 2008). The Kaizara Flora was classified as Eurosinian type by its abundant occurrence of bennettitalean Otozamites and Ptilophyllum (Yamada and Uemura, 2008). This result showed that the Tetori-type flora would have appeared after the Oxfordian in the Tetori Group area, but the exact age of its appearance has not been determined. Our data also implied that the floristic trends were shared between Eurasia and Japan in the Middle to Late Jurassic period, but this implication should be further tested by locating the Oxfordian plants from the Tetori Group.

In this study, two plants are reported from the middle Oxfordian Arimine Formation in the Arimine area, Toyama Prefecture (Figures 1, 2). Although only two species were recognized, they provide sufficient evidence to infer that a Tetori-type flora was not present during this period in the Tetori Group.

Material and geological settings

Plant fossils were collected from locality AR0021 in Arimine, Toyama City, Toyama Prefecture (Figure 1). All specimens are stored in the Palaeobotanical Collections of the National Museum of Nature and Science, Tsukuba (NSM PP).

In this locality, the lower part of the Arimine Formation, consisting of fine-to-medium sandstones of shallow marine origin (Sato and Yamada, 2014), outcrops. The middle Oxfordian age was inferred by the simultaneous occurrence of the ammonoid genera, Perisphinctes (Kranaosphinctes), P. (Dichotomosphinctes), and Ochetoceras (Sato and Yamada, 2014). Details on the collection site are available in Sato and Yamada (2014).

Figure 2.

Current interpretations of stratigraphic horizons bearing the “Kuzuryu Flora,” modified from Yamada and Uemura (2008). Stratigraphic ranges of floras reported from the Tetori Group are summarized in the rightmost column based on Yabe et al. (2003) and Yamada and Uemura (2008) (asterisk indicates the plant fossil assemblage from the Arimine Formation). The stratigraphy in Wakogo, Managawa (locality 5 in Figure 1) is not shown because it has yet to be precisely revised. However, radiometric dating suggests that the plant-bearing horizon in Wakogo is younger than the Tithonian (Kawagoe et al., 2012). Fm, Formation; F1, Flora.

f02_203.jpg

Systematic palaeobotany

Class Bennettiopsida
Order Bennettitales Engler, 1892
Family uncertain
Genus Ptilophyllum Morris, 1840

  • Type species.—Ptilophyllum acutifolium Morris, 1840.

  • Ptilophyllum sp.
    Figure 3 A, B

  • Ptilophyllum sp. A. Yamada and Uemura, 2008, p. 10, fig. 5D–F.

  • Specimens examined.—NSM PP-9925.

  • Description.—One specimen of compound leaf was collected whose apex and base were not preserved. Leaf fragment is 2.8 cm wide by 2.6 cm long. Rachis is ca. 1.3 mm wide and bears leaflets on the adaxial side. Angles between the rachis and leaflets range between 50 and 55 degrees. Leaflets are 12.7–15.7 mm long by 2.1–2.9 mm wide. Leaflet apices are obtusely pointed. Leaflet bases are slightly contracted on the acroscopic side, but decurrent on the basiscopic side. Veins run almost parallel and do not diverge acropetally. Concentration of veins ranges from 41.6 to 47.6 per cm, although veins could be observed in only two leaflets.

  • Remarks.—Distinction among the “cycadophyte” foliar genera Otozamites, Ptilophyllum and Zamites is sometimes difficult when epidermal characters are not available. However, it is suggested that Ptilophyllum could be distinguished from the other two genera by decurrent basiscopic bases of leaflets and veins not diverging acropetally (Rees and Cleal, 2004; McLoughlin and Pott, 2009).

  • The obtained specimen could not be distinguished in leaf shape and leaflet vein concentration from Ptilophyllum sp. A from the Callovian Kaizara Formation in Kuzuryu/Itoshiro area, Fukui Prefecture (Yamada and Uemura, 2008). As reported in Yamada and Uemura (2008), Ptilophyllum sp. A, as well as our specimen, can be assigned either to P. cutchense Morris (1840) emend. Bose and Kasat (1972) or to P. chosiense Kimura, Okubo and Miyahashi (1991). However, specific assignment is not possible without the epidermal characteristics.

  • Figure 3.

    Plant fossils from the Arimine Formation. A, B, Ptilophyllum sp.; A, NSM PP-9925; B, line drawing of A; C–E, Zamites brevipennis; C, compound leaf, NSM PP-9926; D, compound leaf, NSM PP-9927; E, detached leaf, NSM PP-9928. Scale bars indicate 1 cm.

    f03_203.jpg

    Genus Zamites Brongniart, 1828

  • Type species.—Zamites gigas (Lindley et Hutton, 1837) Morris, 1841 emend. Harris, 1969.

  • Zamites brevipennis (Oishi) Takimoto, Ohana and Kimura, 2008
    Figure 3C–E

  • Pseudoctenis brevipennis Oishi, 1940, p. 322, pl. 28, figs. 5, 6; Kimura and Ohana, 1988b, p. 157, pl. 14, fig. 1, text-fig. 20a, b.

  • Zamites sp. A. Kimura and Ohana, 1988a, p. 124, pl. 7, figs. 4, 5.

  • Zamites sp. B. Kimura and Ohana, 1988a, p. 124, text-fig. 14.

  • Zamites sp. D. Kimura and Ohana, 1989, p. 15, pl. 1, fig. 5.

  • Zamites brevipennis (Oishi) Takimoto, Ohana and Kimura, 2008, p. 135. figs. 5.1–5.3.

  • Specimens examined.—NSM PP-9926 (Figure 3C), NSM PP-9927 (Figure 3D), NSM PP-9928 (Figure 3E), NSM PP-9929.

  • Description.—Two fragments of compound leaves (Figure 3C, D) and two detached leaflets (Figure 3E, NSM PP-9929) were collected. Both leaves lacked the apical and basal parts, as well as leaflets on the right side (Figure 3C, D). Leaves are more than 9 cm long (Figure 3C, D). Rachis is slender (i.e., 2.0–2.5 mm wide) and bears leaflets on the upper-lateral side at 75–80 degrees (Figure 3C, D). Leaflets are ca. 4.5 cm long by 1.2–1.3 cm wide (Figure 3C–E) and slightly overlap with adjacent ones (Figure 3C, D). Leaflet apices are obtuse (Figure 3D). Leaflet bases are equally contracted to two-thirds of the widest part (Figure 3C, D) and thickened to form a crescentic elevation (Figure 3C). Upper margins of leaflets are straight. Lower margins of leaflets are almost straight, but start to curve at the apical one-third of each leaflet (Figure 3D). Veins run almost parallel without anastomosis, and fork several times. Concentrations of veins range from 15 to 22 per cm (Figure 3C, E).

  • Remarks.—These specimens were classified as Zamites brevipennis, which was originally described from the Oxfordian Tochikubo Formation, Fukushima Prefecture, northeastern Japan, based on the slender rachis, short leaflets with obtuse apex and equally contracted base, crowded veins, and crescentic elevation at the base of the leaflets (Oishi, 1940; Takimoto et al., 2008). Zamites brevipennis is unique in that the leaflets are short relative to the width, as denoted by the specific epithet. Zamites carruthersii Seward from the Berriasian of the English Wealden (Watson and Sincock, 1992) is another species with short leaflets, but the leaflets are attached to a rachis by a narrow attachment without thickening in Z. carruthersii.

  • Zamites-type leaves were classified as the beimettitalean morphogenus Pterophyllum or the cycadalean morphogenus Pseudoctenis when epidemial characteristics were unavailable (Harris, 1964, 1969). Two Zamites-type leaves have been reported from the Tetori Group, i.e., Pseudoctenis sp. from the Callovian Kaizara Formation in the Kuzuryu/Itoshiro area, Fukui Prefecture (Yamada and Uemura, 2008), and Pterophyllum pachyrachis (Oishi) Kimura and Ohana (1987) from the Tithonian to Berriasian Yambara Formation in the eastern Izumi area, Fukui Prefecture (Oishi, 1940; for stratigraphic horizon of the specimen, see Yamada and Uemura, 2008). Both species have a thick rachis of ca. 1 cm diameter and long leaflets; thus, they are clearly different from Z. brevipennis.

  • Discussion

    It had been widely accepted that Tetori-type floras continuously flourished during the Middle Jurassic (the Bajocian) to Early Cretaceous in the Tetori Group (Kimura, 1958, 1975, 1987, 1988; Yabe et al., 2003). However, this interpretation contradicted the palaeobotanical data indicating that Eurosinian-type vegetation occurred far northward in Eurasia beyond the land of the Tetori Group during the Middle to Late Jurassic (Vakhrameev, 1987, 1991). Recent stratigraphic and palaeobotanical studies suggested that the Tetori-type flora should have appeared after the Oxfordian (Yamada and Uemura, 2008), but it remains to be clarified when the Tetori-type flora first appeared.

    In this study, Ptilophyllum sp. and Zamites brevipennis are described from the Oxfordian Arimine Formation of the Tetori Group distributed in the Arimine area, Toyama Prefecture (Figure 1). This is the first report of Oxfordian plants from the Tetori Group. These two genera are considered as indices of a climate with dry season(s) (Ziegler et al., 1993, 1996; Rees et al., 2000) that prevailed in the Eurosinian province during the Middle Jurassic to Early Cretaceous (Vakhrameev, 1987, 1991). In contrast, these plants have not been reported to date from any flora of the Siberian province, including Tetori-type floras (Kimura, 1987, 1988; Vakhrameev, 1987, 1991).

    Since the plant specimens used in this study were fossilized in shallow marine deposits, they possibly reflect the coastal vegetation only. However, post-Tithonian marine deposits of the Tetori Group include index species of the Siberian-type floras and do not contain these indices of a drier climate (Yamada and Uemura, 2008; T. Yamada, unpublished data). Therefore, it is likely that the typical Tetori-type flora did not flourish during the Oxfordian on the land of the Tetori Group. The Eurosinian-type vegetation is successively present from the late Bathonian to Oxfordian, although more plant fossils should be collected to develop a more comprehensive image of the Oxfordian flora of the Tetori Group.

    Two Eurosinian-type floras were reported from the Oxfordian of Northeast Japan: one from the Tochikubo Formation of the Somanakamura Group in Fukushima Prefecture (Kimura and Ohana, 1988a, b; Takimoto et al., 2008) and the other from the Oginohama Formation of the Ojika Group in Miyagi Prefecture (Kimura and Ghana, 1989). The plant fossil assemblage of the Arimine Formation is too incompletely clarified to compare to those of the Oginohama and Tochikubo formations in a species-by-species manner, but it should be noted that Z. brevipennis commonly occurs from all of these formations (Oishi, 1940; Kimura and Ghana, 1989; Takimoto et al., 2008). The common occurrence may imply that the floristic barrier was weak, if present, which separated the lands of these three formations. Whatever the case may be, plant fossils from the Arimine Formation add evidence that a Eurosinian-type flora prevailed also in the Inner Zone of Southwest Japan, resolving the discrepancy in the Oxfordian floras between Japan and the Eurasian region of East Asia (Vakhrameev, 1987, 1991).

    The oldest plant assemblages of the Tetori-type flora are those from the Tithonian Ushimaru Formation distributed in the Shokawa area of Gifu Prefecture (Kimura, 1958; Maeda, 1961b; Yamada and Uemura, 2008; Figures 1,2). An almost coeval assemblage of the Tetori-type flora was also reported from the Tithonian Ashidani Formation in eastern Izumi, Fukui Prefecture (Kimura, 1958; Yamada and Uemura, 2008; Figures 1, 2). In summary, plant fossils from the Oxfordian Arimine Formation suggest that Tetori-type floras appeared after the Tithonian on the land of the Tetori Group. The Eurosinian-type flora disappeared during the late Oxfordian to Tithonian when deposition was interrupted in the Tetori Group (Sato and Yamada, 2014).

    Acknowledgements

    This study was partly supported by the Research Project of the National Museum of Nature and Science under the name “Historical Development and Origin of Biodiversity under Global Environmental Dynamics.” The Hokuriku Electric Power Company, Ministry of the Environment, and Toyama Prefecture kindly gave me permission to collect specimens in Chubu Sangaku National Park (Chubu Mountain National Park). I am grateful to T. Hayashi, K. Hachiya, and Y. Mizuno for their assistance in the collection of specimens.

    References

    1.

    Bose, M. N. and Kasat, M. L., 1972: The genus Ptilophyllum in India. Palaeobotanist, vol. 19, p. 115–145. Google Scholar

    2.

    Brongniart, A., 1828: Prodrome d'une Histoire des Végétaux Fossiles. Dictionnaire des Sciences Naturelles, vol. 57, p. 1–223. Google Scholar

    3.

    Engler, A., 1892: Syllabus der Vorlesungen über specielle und medicinisch-pharmaceutische Botanik, XXIII + 184 p. Borntraeger, Berlin. Google Scholar

    4.

    Harris, T. M., 1964: The Yorkshire Jurassic Flora II. Caytoniales, Cycadales and Pteridosperms, 191 p. British Museum (Natural History), London. Google Scholar

    5.

    Harris, T. M., 1969: The Yorkshire Jurassic Flora III. Bennettitales, 186 p. British Museum (Natural History), London. Google Scholar

    6.

    Kawagoe, Y., Sano, S., Orihashi, Y., Obara, H., Kouchi, Y. and Otoh, S., 2012: New detrital zircon age data from the Tetori Group in the Mana and Itoshiro areas of Fukui Prefecture, central Japan. Memoir of the Fukui Prefectural Dinosaur Museum, vol. 11, p. 1–18. Google Scholar

    7.

    Kimura, T., 1958: On the Tetori flora (Part 1). Mesozoic plants from the Kuzuryu Sub-Group, Tetori Group, Japan. Bulletin of the Senior High School Attached to the Tokyo University of Education, vol. 2.2. p. 1–47. Google Scholar

    8.

    Kimura, T., 1975: Middle-Late Early Cretaceous plants newly found from the upper course of the Kuzuryu River Area, Fukui Prefecture, Japan. Transactions and Proceedings of the Palaeontological Society of Japan, New Series, no. 98, p. 55–93. Google Scholar

    9.

    Kimura, T., 1987: Recent knowledge of Jurassic and Early Cretaceous floras in Japan and phytogeography of this time in East Asia. Bulletin of the Tokyo Gakugei University, Section 4, vol. 39, p. 87–115. Google Scholar

    10.

    Kimura, T., 1988: Jurassic macrofloras in Japan and palaeophytogeography in East Asia. Bulletin of the Tokyo Gakugei University, Section 4, vol. 40, p. 147–164. Google Scholar

    11.

    Kimura, T., 2000: Early Cretaceous climatic provinces in Japan and adjacent regions on the basis of fossil land plants. In, Okada, H. and Mateen N. J. eds., Cretaceous Environments of Asia. Developments in Palaeontology and Stratigraphy, vol. 17, p. 155–161. Elsevier, Amsterdam. Google Scholar

    12.

    Kimura, T. and Ghana, T., 1987: Middle Jurassic and some Late Liassic plants from the Toyora Group, southwest Japan (II). Bulletin of the National Science Museum, Series C, vol. 13, p. 115–148. Google Scholar

    13.

    Kimura, T. and Ghana, T., 1988a: Late Jurassic plants from the Tochikubo Formation (Oxfordian), Somanakamura Group, in the Outer Zone of Northeast Japan. I. Bulletin of the National Science Museum, Series C, vol. 14, p. 103–133. Google Scholar

    14.

    Kimura, T. and Ghana, T., 1988b: Late Jurassic plants from the Tochikubo Formation (Oxfordian), Somanakamura Group, in the Outer Zone of Northeast Japan. II. Bulletin of the National Science Museum, Series C, vol. 14, p. 151–185. Google Scholar

    15.

    Kimura, T. and Ghana, T., 1989: Late Jurassic plants from the Oginohama Formation, Oshika Group, in the Outer Zone of Northeast Japan. (I). Bulletin of the National Science Museum, Series C, vol. 15. p. 1–24. Google Scholar

    16.

    Kimura, T., Okubo, A. and Miyahashi, H., 1991: Cuticular study of Ptilophyllum leaves from the Lower Cretaceous Choshi Group, in the Outer Zone of Japan. Bulletin of the National Science Museum, Series C, vol. 17, p. 129–152. Google Scholar

    17.

    Kimura, T. and Sekido, S., 1976: Mesozoic plants from the Akaiwa Formation (Upper Neocomian), the Itoshiro Group, Central Honshu, Japan. Transactions and Proceedings of the Palaeontological Society of Japan, New Series, no. 103, p. 343–378, pls. 36–39. Google Scholar

    18.

    Kusuhashi, N., Matsumoto, A., Murakami, M., Tagami, T., Hirata, T., Iizuka, T., Handa, T. and Matsuoka, H., 2006: Zircon U-Pb ages from tuff beds of the upper Mesozoic Tetori Group in the Shokawa district, Gifu Prefecture, central Japan. Island Arc, vol. 15, p. 378–390. Google Scholar

    19.

    Lindley, J. and Hutton, W., 1837: The Fossil Flora of Great Britain; or, Figures and Descriptions of the Vegetable Remains found in a Fossil State in this Country, Part 3, 208 p., pls. 157–230. John Ridgeway, London. Google Scholar

    20.

    Maeda, S., 1961a: The Tetori Group along the Asuwa River in Fukui Prefecture. Journal of Geography, vol. 70, p. 65–69. (in Japanese with English abstractGoogle Scholar

    21.

    Maeda, S., 1961b: On the geological history of the Mesozoic Tetori Group in Japan. Journal of College of Arts and Sciences, Chiba University, Natural Sciences Series, vol. 3, p. 369–426. (in Japanese with English abstractGoogle Scholar

    22.

    McLoughlin, S. and Pott, C., 2009: The Jurassic flora of Western Australia. GFF, vol. 131, p. 113–136. Google Scholar

    23.

    Morris, J., 1840: Appendix and P1. XXI. In, Grant, C. W. ed., Memoir to Illustrate a Geological Map of Cutch, p. 289–329. Transactions of the Geological Society of London, 2nd Series, vol. 5. The Geological Society of London, London. Google Scholar

    24.

    Morris, J., 1841: Remarks upon the recent and fossil Cycadaceae. Annals and Magazine of Natural History, vol. 7, p. 110–120. Google Scholar

    25.

    Oishi, S., 1940: The Mesozoic floras of Japan. Journal of the Faculty of Sciences, Hokkaido Imperial University, Section 4, vol. 5, p. 123–480. Google Scholar

    26.

    Rees, P. M. and Cleal, C. J., 2004: Lower Jurassic floras from Hope Bay and Botany Bay, Antarctica. Special Papers in Palaeontology, no. 72. p. 5–89. Google Scholar

    27.

    Rees, P. M., Ziegler, A. M. and Valdes, P. J., 2000: Jurassic phytogeography and climates: new data and model comparisons. In, Huber, B. T., Macleod, K. G. and Wing, S. L. eds., Warm Climates in Earth History, p. 297–318. Cambridge University Press, Cambridge. Google Scholar

    28.

    Sato, T., Asami, T., Hachiya, K. and Mizuno, Y., 2008: Discovery of Neocosmoceras, a Berriasian (early Cretaceous) ammonite, from Mitarai in the upper reaches of the Shokawa River in Gifu Prefecture, Japan. Bulletin of the Mizunami Fossil Museum, vol. 34, p. 77–80. Google Scholar

    29.

    Sato, T., Hachiya, K. and Mizuno, Y., 2003: Latest Jurassic-Early Cretaceous ammonites from the Tetori Group in Shokawa, Gifu Prefecture. Bulletin of the Mizunami Fossil Museum, vol. 30, p. 151–167. Google Scholar

    30.

    Sato, T. and Yamada, T., 2005: Early Tithonian (Late Jurassic) ammonite Parapallasiceras newly discovered from the Itoshiro Subgroup (Tetori Group) in the Hida Belt, northern Central Japan. Proceedings of the Japan Academy, Series B, vol. 81, p. 267–272. Google Scholar

    31.

    Sato, T. and Yamada, T., 2014: A new Oxfordian (Late Jurassic) ammonite assemblage from the Arimine Formation (Tetori Group) in the Arimine area, southeastern Toyama Prefecture, northern Central Japan. Bulletin of the National Museum of Nature and Science, Series C, vol. 40, p. 21–55. Google Scholar

    32.

    Takimoto, H., Ohana, T. and Kimura, T., 2008: New fossil plants from the Upper Jurassic Tochikubo and Tomizawa formations, Somanakamura Group, Fukushima Prefecture, Northeast Japan. Paleontological Research, vol. 12, p. 129–144. Google Scholar

    33.

    Vakhrameev, V. A., 1987: Climates and the distribution of some gymnosperms in Asia during the Jurassic and Cretaceous. Review of Palaeobotany and Palynology, vol. 51, p. 205–212. Google Scholar

    34.

    Vakhrameev, V. A., 1991 : Jurassic and Cretaceous Floras and Climates of the Earth, 318 p. Cambridge University Press, Cambridge. Google Scholar

    35.

    Watson, J. and Sincock, C. A., 1992: Bennettitales of the English Wealden. Monograph of the Palaeontographical Society, vol. 145, p. 1–228. pls. 1–23. Google Scholar

    36.

    Yabe, A., Terada, K. and Sekido, S., 2003: The Tetori-type flora, revisited: a review. Memoir of the Fukui Prefectura1 Dinosaur Museum, vol. 2, p. 23–42. Google Scholar

    37.

    Yamada, T. and Uemura, K., 2008: The plant fossils from the Raizara Formation (Callovian, Jurassic) of the Tetori Group in the Izumi district, Fukui Prefecture, Central Japan. Paleontological Research, vol. 12, p. 1–17. Google Scholar

    38.

    Ziegler, A. M., Parrish, J. M., Yao, J., Gyllenhaal, E. D., Rowley, D. B., Parrish, J. T., Shangyou, N., Bekker, A. and Huiver, M. L., 1993: Early Mesozoic phytogeography and climate. Philosophical Transactions of the Royal Society of London, Series B, vol. 341, p. 297–305. Google Scholar

    39.

    Ziegler, A. M., Rees, P. M., Rowley, D. B., Bekker, A., Qing, L. and Huiver, M. L., 1996: Mesozoic assembly of Asia: constraints from fossil floras, tectonics, and paleomagnetism. In, Yin, A. and Harrison, M. eds., The Tectonic Evolution of Asia, p. 371–400. Cambridge University Press, Cambridge. Google Scholar
    © by the Palaeontological Society of Japan
    Toshihiro Yamada "Plant Fossils from the Arimine Formation (Oxfordian, Jurassic) of the Tetori Group in Arimine, Toyama Prefecture, Central Japan," Paleontological Research 22(3), 203-209, (1 July 2018). https://doi.org/10.2517/2017PR017
    Received: 10 July 2017; Accepted: 25 August 2017; Published: 1 July 2018
    KEYWORDS
    Arimine Formation
    Oxfordian
    Ptilophyllum
    Tetori Group
    Tetori-type flora
    Zamites
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