Bulletin of the Geological Survey of Japan, vol. 70 (1/2), p. 195–209, 2019

Notes and Comments

Late Miocene polycystine radiolarians of the Japan Sea(IODP Exp. 346 Site U1425)
Kenji M. Matsuzaki1,* and Takuya Itaki2
Kenji M. Matsuzaki and Takuya Itaki (2019) Late Miocene polycystine radiolarians of the Japan Sea (IODP
Exp. 346 Site U1425). Bull. Geol. Surv. Japan, vol. 70 (1/2), p. 195–209, 1 figure, 2 tables, 9 plates.
Abstract: In this study, we have illustrated the 84 species/species group of polycystine radiolarians,
which were commonly encountered in the upper Miocene sediments at the Site U1425 of the Integrated
Ocean Drilling Program (IODP) in the Japan Sea. The micro-photographs of these species/species groupare illustrated in 9 plates.
Keywords: Integrated Ocean Drilling Program, late Miocene, Japan Sea, Polycystine radiolarians

1. Introduction

2. Material and methods

The Integrated Ocean Drilling Program (IODP)
Expedition 346 retrieved seven sites covering a wide
latitudinal and depth range in the Japan Sea and the East
China Sea. The sediment cores collected in the Japan Sea
cover the Holocene to the middle Miocene (e.g. Tada etal., 2015; Kamikuri et al., 2017). Polycystine radiolarians
are Protista bearing skeletons of amorphous silica andthey are the unique microfossil group, which can inhabit
intermediate and deep-water (Suzuki and Not, 2015).
They are also usually used as a biostratigraphic andpaleoceanographical index in the North Pacific, where
the preservation of carbonates is low in the deep-sea
sediments. In the deep-sea sediment of the Japan Sea, thepreservation of carbonates is lower than those recorded in
the North Pacific because of a calcite compensation depth
about 2,000 m (e.g. Ujiie and Ichikura, 1973), whereas
radiolarians are usually well-preserved in such carbonatepoor sediments in the Japan Sea. Therefore, polycystineradiolarians were examined at all sites recovered in theJapan Sea during the expedition 346 to define their local
biostratigraphy and establish a preliminary depth-age
model at each drilled site (Kamikuri et al., 2017). In thisstudy, we propose to show micro-photographs of theradiolarian species and/or species group, which often
occurred from the upper Miocene of IODP Exp. 346 Site
U1425.

In this study, we have analyzed radiolarians from 88
sediment core samples covering the late Miocene collectedfrom Sites U1425 drilled during IODP Expedition 346.
The Site U1425 is located at 39°
29.44’
N and 134°
26.55’
E(Fig. 1), in the central Japan Sea, at the middle of the
Yamato Bank, where the water depths is 1,909 m water
depth. The 88 samples were freeze-dried, and treated withdiluted hydrogen peroxide (H2O2) (15%) (50 ml of H2O2
at concentration of 30% diluted in 100 ml of water) andhydrochloric acid (15%) (40 ml of HCl at concentrationof 35–37% diluted in 100 ml of water) to remove organicand calcareous matter. The undissolved residue in eachsample was sieved over a 45-µm screen following themethod proposed in Tada et al. (2015). The examination ofpolycystine radiolarians was carried out under an optical
microscope Nikon Eclipse E 200 at magnifications of
100× to 400×. The photomicrographs were taken underan optical microscope at magnifications of 400× using
a digital camera Olympus SP-600UZ, with an opticalzoom of 5.0–75.0 mm, which is set on the used optical
microscope.

3. Radiolarian fauna
Totally 84 species and species group, including 1
collodarian, 44 spumellarians and 39 nassellarians wereencountered during the late Miocene in the Japan Sea.

1

Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo (7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan)

2

AIST, Geological Survey of Japan, Research Institute of Geology and Geoinformation*

Corresponding author: K.M. Matsuzaki, Email: km.

present address: Atmosphere and Ocean Research Institute, the University of Tokyo (5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564 Japan)@aori.u-tokyo.ac.jp− 195 −

Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Location of the studied site and generaloceanographic setting of the Japan Sea

50°N

Bathymetry :MamiyaStrait

KC: Kuroshio Current
TWC: Tsushima Warm Current
TWC B1: Tsushima Warm Current
Branch 1
TWC B2: Tsushima Warm Current
Branch 2
TWC B3: Tsushima Warm Current
Branch 3
LCC: Leman Cold Current

50 m
100 m

Okhotsk
Sea

250 m
500 m
750 m
1000 mSoya
Strait45°N
C
LC Japan1500 m2000 mTsugaru
StraitSite U1425

40°N

ido

kka

Ho

Sea

1250 m2500 m3000 mTWC B3

3500 mTWC B2
1

35°N

TWC

T WC B

4000 man)
Jap nshu(Ho4500 mTsushima
Strait5000 m
5500 mKC
Northwest
Pacific

China
Sea

130°E

135°E

140°E

6000 mOcean Data View

30°N East

6500 m145°E

Photomicrographs of all forms are shown from plate 1 toplate 9. For all these taxa, we have provided taxonomic
names and its related taxonomic references (Tables 1 and 2).
Acknowledgement
We would like to thank Drs. Shin-ichi Kamikuri andIsao Motoyama for having reviewed our manuscript andproviding us helpful suggestions. We also wish to thankDr. Noritoshi Suzuki for providing us valuable taxonomic
comments and remarks. We would like to thank theIntegrated Ocean Drilling Program (IODP) Expedition
346 for provide us the samples. We also wish to thankthe Kochi Core Center (KCC) and its curators for theirsampling assistance. This work was supported by the JSPS
Research Fellowship for Young Scientist grant 16J02142(MKM). This work was also finally partially financedby the IODP Exp. 346 After Cruise Research Program,
JAMSTEC.

References
Blueford, J. R. (1982) Miocene actinommid Radiolaria
from the equational Pacific. Micropaleontology, 28,
189–213.
Campbell, A. S. and Clark, B. L. (1944) Miocene
radiolarian faunas from southern California. Geol.

Fig. 1 This map has been modified from
Matsuzaki et al. (2018) and shows thelocation of Integrated Ocean Drilling
Program (IODP) Expedition 346 Site
U1425 and the majors paleoceanographic
setting of the Japan Sea. The base map isfrom Ocean Data View 4 (Schlitzer, 2016).

Soc. Amer., Spec. Pap., no. 51, 1–76.
Dogiel, V. A. and Reshetnyak, V. V. (1952) Materialy
po radiolyariyam severo-zapadnoy chasti tikhogo
okeana. Issledovanya Dalnevostochnykh Morei SSSR,
3, 5–36.
Ehrenberg, C. G. (1873) Mikrogeologische Studien uberdas kleinste Leben der Meeres-Tiefgrunde aller Zonen
und dessen geologischen Einﬂuss. Abhandlungen der
Koniglichen Akademie der Wissenschaften zu Berlin,
1872, 131–399.
Funakawa, S. (1995) Lophophaeninae (Radiolaria)
from the Upper Oligocene to Lower Miocene andintrageneric variation in their internal skeletal
structures. Jour. Geosci., Osaka City Univ., 38, 13–61.
Gladenkov, Y. and Devyatkin, E. (1992) Detal’
noeRaschlenenie Neogena Kamchatk. Ordena Trudnovogo
Krasnogo Znameni Geologicheskiy Institut, Rossiyskaya
Akademiya Nauk, 478, 55–200.
Haeckel E. (1887) Report on the Radiolaria collectedby H.M.S. Challenger during the years 1873–1876.
Report on the Scientific Results of the Voyage of
H.M.S. Challenger during the year 1873–1876,
Zoology, 18, 1–1803
Itaki T. (2009) Last Glacial to Holocene polycystineradiolarians from the Japan Sea. News of Osaka
Micropaleontol. (NOM), Spec. Vol., no. 14, 43–89.

− 196 −

Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Kamikuri, S. (2010) New late Neogene radiolarian species
from the middle to high latitudes of the North Pacific.
Revue Micropaleontol., 53, 85–106.
Kamikuri, S. (2012) Evolutionary changes in the biometryof the fossil radiolarian Stichocorys peregrina lineage
in the eastern equatorial and eastern North Pacific.
Marine Micropaleontol., 90, 13–28.
Kamikuri, S., Itaki, T., Motoyama, I. and Matsuzaki,
K. M. (2017) Radiolarian biostratigraphy frommiddle Miocene to late Pleistocene in the Japan Sea.
Paleontol. Res., 21, 397–421.
Kozlova, G. E. (1960) Radiolyarii srednego i verkhnego
miotsena Severnogo Sakhalina. In Subbotina, N.N.,ed., Mikrofauna SSSR XI. Trudyi Vsesoyuznogo
Nauchno-Issledovatel’skogo Geologicheskogo Instituta,
Gosgortekhizdat, 153, 307–325.
Kruglikova, S. B. (1974) Kharakternye vidy radiolayriy v
donnykh osadkakh voreal’
noi zony Tikhogo okeana.
In Zhuze, A. P., ed., Mikropaleontologiya Okeanov i
Morey, Akaemiya Nauk SSSR, Okeanograficheskaya
Komissiya, Nauka, Moskow (in Russian with English
abstract), 187–196.
Lazarus, D., Faust, K. and Popova-Goll, I. (2005) New
species of prunoid radiolarians from the Antarctic
Neogene. Jour. Micropalaeontol., 24, 97–121.
Matsuzaki, K. M., Suzuki, N. and Nishi, H. (2015) Middle
to Upper Pleistocene Polycystine Radiolarians fromHole 902-C9001C, Northwestern Pacific. Paleontol.
Res., 19, no. s1, 1–77.
Matsuzaki, K. M., Itaki, T., Tada, R. and Kamikuri, S.
(2018) Paleoceanographic history of the Japan Sea
over the last 9.5 million years inferred from radiolarianassemblages (IODP Expedition 346 Sites U1425 andU1430), Progress in Earth and Planetary Science,5(54), 1–33. doi: 10.1186/s40645-018-0204-7.
Martin, G. C. (1904) Radiolaria, in Miocene. Maryland
Geological Survey, The John Hopkins Press, 447–459.
Morley, J. J. and Nigrini, C. (1995) Miocene to Pleistocene
radiolarian biostratigraphy of North Pacific Sites
881, 884, 885, 886 and 887. In Rea, D. K., Basov, I.
A., Scholl, D. W. and Allan, J. F., eds., Proc. Ocean
Drilling Program, Sci. Results, 145, Ocean Drilling
Program, College Station, 55–91.
Motoyama, I. ( 1996 ) Late Neogene radiolarianbiostratigraphy in the subarctic northwest Pacific.
Micropaleontology, 42, 221–262.
Motoyama, I., Kurihara, T. and Itaki, T. (2017)
Neogene biosiliceous sedimentary sequence andradiolarian biostratigraphy in the Tainai area, Niigata
Prefecture. Sci. Rep. Niigata Univ. (Geology), no. 22(Supplement), 91–102.
Nakaseko, K. and Nishimura, A. (1971) A new species ofActinomma from the Neogene Formation, Japan. Sci.
Rep. Coll. General Educ., Osaka Univ., 20, 67–70.
Nigrini, C. (1977) Tropical Cenozoic Artostrobiidae(Radiolaria). Micropaleontology, 23, 241–269.
Nigrini, C. and Lombari, G. (1984) A guide to Miocene

Radiolaria. Cushman Foundation for ForaminiferalRes., Spec. Publ., no. 22, i-xvii; S1-S102; N1-N206,
33 plates.
Petrushevskaya, M. G. (1971) Radiolyarii Nassellaria v
planktone Mirovogo okeana. Trudyi Zoologicheskogo
Instituta, Akademiya Nauk, SSSR, 9, 1–294. (inRussian)Petrushevskaya, M. G. (1975) Cenozoic radiolarians of
the Antarctic, Leg 29, DSDP. Init. Rep. Deep-Sea
Drilling Project, U.S. Government Printing Office,29, 541–675. Washington, D. C.
Popofsky, A. (1908) Die Radiolarien der Antarktis (mit
Ausnahme der Tripyleen). Deutsche SüdpolarExpedition 1901–1903, Zoologie, 10, 185–305.
Popofsky, A. ( 1912 ) Die Sphaerellarien desWarmwassergebietes. Deutsche Sudpolar-Expedition
1901-1903, Zoologie, 5, 73–159.
Popofsky, A. ( 1913 ) Die Nassellarien desWarmwassergebietes. Deutsche Südpolar-Expedition
1901–1903, Zoologie, 14, 216–416.
Renaudie, J. and Lazarus, D. B. (2012) New species of
Neogene radiolarians from the Southern Ocean. Jour.
Micropalaeontol., 31, 29–52.
Renaudie, J. and Lazarus, D. B. (2013) New species of
Neogene radiolarians from the Southern Ocean–Part
II. Jour. Micropalaeontol., 32, 59–86.
Schlitzer, R. (2016) Ocean Data View, http://odv.awi.de,
2016.
Shilov, V. V. (1995) Miocene-Pliocene radiolarians fromLeg 145, North Pacific. In Rea, D. K., Basov, I. A.,
School, D. W. and Allan, J. F., eds., Proc. Ocean
Drilling Program, Sci. Results, 145, Ocean Drilling
Program, College Station, 93–116.
Sugiyama, K. (1993) Skeletal structures of Lower andMiddle Miocene Lophophaenids (Radiolaria) from
central Japan. Trans. Proc. Palaeontol. Soc. Japan,
New Ser., no. 169, 44–72.
Suzuki, N. (2006) Ontogenetic growth and variation in
the skeletal structure of two late neogene sphaeropylespecies (polycystina radiolarians). Jour. Paleontol.,
80, 849–866.
Suzuki, N. and Not, F. (2015) Biology and ecology ofRadiolaria. In Ohtsuka, S., Suzaki, T., Horiguchi,T., Suzuki, N. and Not, F., eds., Marine Protists,
Springer, Tokyo, 179–222.
Tada, R., Murray, R. W., Alvarez Zarikian, C. A., Anderson,
Jr. W. T., Bassetti, M. A., Brace, B. J., Clemens, S.
C., da Costa, G. M. H., Dickens, G. R., Dunlea, A.
G., Gallagher, S. J., Giosan, L., Henderson, A. C.
G., Holbourn, A. E., Ikehara, K., Irino, T., Itaki,T., Karasuda, A., Kinsley, C. W., Kubota, Y., Lee,G. S., Lee, K. E., Lofi, J., Lopes, C., Peterson, L.
C., Saavedra-Pellitero, M., Sagawa, T., Singh, R.
K., Sugisaki, S., Toucanne, S., Wan, S., Xuan, C.,
Zheng, H. and Ziegler, M. (2015) Site U1425. In Tada,
R., Murray, R. W., Alvarez Zarikian, C. A. and theExpedition 346 Scientists, Proc. IODP, 346: College− 197 −

Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Station, TX (Integrated Ocean Drilling Program). doi:
10.2204/iodp.proc.346.106.2015
Takahashi, K. (1991) Radiolaria: Flux, ecology, andTaxonomy in the Pacific and Atlantic. Ocean andBiocoenosis Series, Wood Hole Oceanographic
Institutions, no. 3, 1–301.
Ujiie, H. and Ichikura, M. (1973) Holocene to uppermost
Pleistocene in a piston core from off San’in District,
Sea of Japan. Trans. Proc. Paleontol. Soc. Japan, no.
91, 137–150.
Vitukhin, V. S. (1993) Subdivision of the Russian Far
East Cenozoic sediments based on Radiolaria.

Transactions, Geol. Inst., Russian Academy Sci., 485,
1–105.
Zhang, L. and Suzuki, N. (2017) Taxonomy and species
diversity of Holocene pylonioid radiolarians fromsurface sediments of the northeastern Indian Ocean.
Palaeontologia Electronica, no. 3, 1–68.

Recieved Feburuary 23, 2018
Accepted September 18, 2018
Published on-line January 18, 2019

IODP Exp. 346 Site U1425 から産出した日本海の後期中新世放散虫
松崎賢史・板木拓也
要 旨
本研究では，日本海で実施された国際深海掘削計画（IODP）Expedition 346の掘削サイトU1425で頻繁に産出した上部
中新統の放散虫化石84種/種群について報告している．これらの顕微鏡写真を9図版に図示した．

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Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Table 1 Taxonomic references of the encountered Collodarians and Spumellarians
Species nameplate(s)-Figure(S)Taxonomic references

Rhizosphaera aff. variabilium (Nakaseko)

1.1-1.2

Gladenkov and Devyatkin, 1992, pl. 32, fig. 2

Hexaconthium minerva Kamikuri

1.3

Kamikuri, 2010, p. 97-98, figs. 12a-12b; 16a-16b

Rhizosphaera urumica Vituchin

1.4

Vitukhin, 1993, p. 87-88, pl. 30, fig. 5

Hexastylus spp. sensu Nigrini and Lombari

1.5

Nigrini, and Lombari, 1984, S 17, Pl. 3, figs. 1a-1c

Acrosphaera muse Kamikuri

1.6

Kamikuri, 2010, p. 96-97, figs. 4a-6

Rhizosphaera sp. A

1.7

this study

Cenosphaera cf. compacta Haeckel

1.8

Blueford, 1982, p. 193-194, pl. 1, figs. 3, 4

Actinomma robusta (Kling) juvenile form

1.9, 1.11

Suzuki, 2006, p. 863-865, figs. 11.1-11.28

Actinomma aff. okurai Nakaseko and Nishimura

1.10, 1.12

Nakaseko and Nishimura, 1971, p. 68, pl. 1, figs. 1-8

Axoprunum bispiculum (Popofsky)

1.13

Popofsky, 1912, p. 91, pl. 2, fig. 2

Druppatractus irregularis Popofsky

1.14

Blueford, 1982, p. 204, 206, pl. 6, figs. 7a, 7b

Stylosphaera pyriformis (Bailey)

1.15

Matsuzaki et al ., 2015, p. 12, Figs. 5.10

Perichlamydium scutaeforme Campbell and Clark

2.1

Campbell and Clark, 1944, Pl. 3, Fig. 15 only

Perichlamydium cf. praetextum (Ehrenberg)

2.2

Petrushevskaya, 1975, p. 575, pl. 6, fig. 10

Stylochlamydium cf. venustum (Bailey)2.3-2.4

Matsuzaki et al ., 2015, p. 28, Figs. 4.2-4.4

Spongotrochus sp. A

2.5

This study

Spongodiscus cauletti group Kamikuri

2.6-2.7

Kamikuri, 2010, p. 94, Pl. 4, Figs. 1-4

Spongopyle osculosa Dreyer

2.9

Matsuzaki et al ., 2015, p. 23, Figs. 4.12-4.13

Flustrella spp. (young forms)

2.10-2.11

This study

Spongodiscus sp. A

2.14

This study

Flustrella sp. A

2.8, 2.12- 2.13, 2.15-2.19

This study

Spongodiscidae juveniles spp.

2.20-2.21

This study

Stylodictya tenuispina Jørgensen group2.22-2.27

Matsuzaki et al ., 2015, p. 27-28, Figs. 4.20

Tetrapyle cf. circularis Haeckel

3.1

Zhang and Suzuki, 2017, p. 15-18, Figs. 8-9

Tetrapyle cf. fruticosa (Tan and Chen)

3.2

Zhang and Suzuki, 2017, p. 18-19, Fig. 10

Phorticium cf. polycladum Tan and Tchang

3.3-3.4, 3.8

Zhang and Suzuki, 2017, p. 43-45, Fig. 12

Prunulum coccymelia Haekcel group

3.5-3.6, 3.11, 3.14-3.18

Haeckel, 1887, p. 313, pl. 39, fig. 4

Phorticium sp. A

3.7

This study

Phorticium aff. scitulum Zhang and Suzuki

3.9-3.10, 3.12-3.13

Zhang and Suzuki, 2017, p. 45-47, Fig. 26

Sphaerolarnacillium sp. A

3.19-3.26

This study

Larcopyle aff. polyacantha (Campbell and Clark)

4.1-4.4

Motoyama et al ., 2017, Fig. 9.12 only

Larcopyle weddellium Lazarus, Faust and Popova-Goll group

4.5-4.14

Lazarus et al ., 2005, p. 117, 119, pl. 10, figs. 1-14

Larcopyle sp. A

4.15

This study

Larcopyle labyrinthusa Lazarus, Faust and Popova-Goll

4.16-4.17

Lazarus et al ., 2005, p. 111, 119, pl. 5, figs. 14-24

Larcopyle sp. B

4.18

This study

Lithelius sp. A

4.19

This study

Lithelius cf. nautiloides (Popofsky)

4.20

Matsuzaki et al ., 2015, p. 37, Fig. 6.29

Lithelius sp. B

4.21

This study

Lithelius sp. C

4.22-4.23

This study

Lihelius barbatus Motoyama

5.1-5.4, 5.7

Motoyama, 1996, p. 243, pl. 3, figs. 11-14

Spiremaria cf. decens Kozlova

5.5-5.6, 5.8-5.11

Kozlova, 1960, p. 315-316, pl. 4, fig. 3

Lithelidae gen et sp. indet

5.12, 5.16-5.17

This study

Lithelius aff. spiralis (Ehrenberg) group

5.13-5.15

Matsuzaki et al ., 2015, p. 38, Fig. 6.31

Phacodiscus aff. calvertense (Martin)

5.18-5.19

Martin, 1904, p. 456, pl. 30, fig. 17

Lithelius klingi Kamikuri

5.20-5.21

Kamikuri, 2010, p. 95-96, pl. 4, figs. 9-14

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Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Table 2 Taxonomic references of the encountered Nassellarians

Species namePlate (s)-Figure (s)Taxonomic references

Dendrospyris sp. A

6.1

This study

Dendrospyris sp. B

6.2-6.3

This study

Dendrospyris sp. C

6.4, 6.6

This study

Dendrospyris sp. D

6.5

This study

Undet. Triospyridae

6.7This study

Dendrospyris sp. E

6.8

This study

Dendrospyris cf. eurus Kamikuri

6.9-6.10

Kamikuri, 2010, p.100, Pl. 5, figs. 19-22 only

Zygocircus archicircus Popofsky

6.11-6.12

Popofsky, 1913, p. 285-286, text-fig. 13

Zygocircus ? sp. A

6.13

This study

Steganocubus sp. A

6.14-6.16

This study

Peridium sphaerum Funakawa

6.17-6.19

Funakawa, 1995, p. 21-22, pl. 2, figs. 1a-4b

Steganocubus ? sp.

6.20

This study

Cryptogyrus aff. trachylobus Sugiyama

6.21-6.22

Sugiyama, 1993, p. 65, 67-68, fig. 19.1a-19.5, 20.1a-20.2b

Lophophaenidae gen. et sp. indet.

6.23

This study

Botryopera ? gibbera Renaudie and Lazarus

6.24-6.27

Renaudie and Lazarus, 2012, p. 47, pl. 7, figs. 3A-6B

Pseudodictyophimus cf. elegans Dogiel and Reshetnyak

6.28

Dogiel and Reshetnyak, 1952, p. 14-15, fig. 7

Pseudodictyophimus sp. A

6.29

This study

Siphocampe arachnea/lineata (Ehrenberg) group6.30-6.31

Nigrini, 1977, p. 256, pl.3, figs. 7-8

Botryostrobus bramlettei Campbell and Clark) group6.32-6.33

Nigrini and Lombari, 1984, N 175-N 176, Pl. 31, figs. 2a-2c

Botryocampe aff. robusta (Kruglikova)

6.34-6.35

Kruglikova, 1974, p. 194, pl. 2, figs. 15-19

Botryopera? daleki

6.36

Renaudie and Lazarus, 2013, p. 68, pl. 6, figs. 1A-1C, 4A-4B

Cycladophora nakasekoi Motoyama

7.1-7.14

Motoyama, 1996, p. 243-246, Pl. 4, figs. 1-3

Cycladophora cf. nakasekoi Motoyama

7.15-7.22

Motoyama, 1996, p. 243-246, Pl. 4, figs. 1-3

Cycladophora cf. sphaeris (Popova)

7.23

Popova 1989, p. 73, pl. 11, fig. 17, pl. 12, fig. 3

Cycladophora sphaeris (Popova)

7.24-7.26

Popova 1989, p. 73, pl. 11, fig. 17, pl. 12, fig. 3

Cycladophora cosma cosma Lombari and Lazarus

7.27-7.28

Morley and Nigrini, 1995, p. 81, pl. 4, fig. 2

Cycladophora aff. cornuta (Bailey)

7.29

Kruglikova, 1974, p. 193-194, pl. 2, figs. 12-14

Stichocorys delmontensis (Campbell and Clark)

8.1

Kamikuri, 2012, Pl. 1, figs. 4, 8 only

Stichocorys peregrina (Riedel) "equatorial form"

8.2-8.8, 8.11

Kamikuri, 2012, Pl. 2, figs. 1-9

Stichocorys peregrina (Riedel) "North Pacific form"

8.9-10, 8.12-8.21

Kamikuri, 2012, Pl. 3, figs. 1-12

Stichocorys sp. A

8.22-8.23

This study

Lychnocanoma magnacornuta Sakai

9.1

Motoyama, 1996, p. 248, pl. 5, figs. 10-11

Lychnocanoma parallelipes Motoyama

9.2

Motoyama, 1996, p. 248, 250, pl. 5, figs. 12a-14

Lipmanella redondoensis (Campbell & Clark)

9.3-9.4

Shilov, 1995, p. 110, pl. 3 fig. 5

Cinclopyramis sp.A

9.5-9.6

This study

Cyrtolagena cuspidata (Bailey)9.7-9.8

Petrushevskaya, 1971, pl. 89, figs. 4-6

Cornutella bimarginatus (Haeckel)

9.9-9.12

Gladenkov and Devyatkin, 1992, pl. 34, fig. 8

Cornutella trochus Ehrenberg

9.13-9.15

Ehrenberg, 1873, p. 286-287, pl. 9, fig. 14

Carpocanarium papillosum (Ehrenberg) group9.16-9.21

Takahashi, 1991, p. 132, pl. 45, figs. 16,17− 200 −

Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Plate 1

1-2: Rhizosphaera aff. variabilium (Nakaseko) (346-U1425B-34H4-46-48 cm); 3: Hexaconthium minerva Kamikuri(346-U1425B-28H3-149-147 cm); 4: Rhizosphaera urumica Vituchin (346-U1425B-CC-12-17 cm); 5: Hexastylus spp.
sensu Nigrini and Lombari (346-U1425B-34H4-46-48 cm); 6: Acrosphaera muse Kamikuri (346-U1425B-CC-12-17 cm); 7:
Rhizosphaera sp. A (346-U1425B-34H4-46-48 cm); 8: Cenosphaera cf. compacta Haeckel (346-U1425B-47H1-91-93 cm); 9,
11: Actinomma robusta (Kling) juvenile form (9. 346-U1425B-47H1-91-93 cm; 11: 346-U1425B-28H3-147-149 cm); 10, 12:
Actinomma aff. okurai Nakaseko and Nishimura (10. 346-U1425B-34H4-46-48 cm; 12. 346-U1425B-47H1-91-93 cm); 13:
Axoprunum bispiculum (Popofsky) (346-U1425B-34H4-46-48 cm); 14: Druppatractus irregularis Popofsky (346-U1425B47H1-91-93 cm); 15: Stylosphaera pyriformis (Bailey) (346-U1425B-47H1-91-93 cm).
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Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Plate 2

1: Perichlamydium scutaeforme Campbell and Clark (346-U1425B-28H3-147-149 cm); 2: Perichlamydium cf. praetextum(Ehrenberg) (346-U1425B-28H3-147-149 cm); 3-4: Stylochlamydium cf. venustum (Bailey) (346-U1425B-34H4-46-48 cm); 5:
Spongotrochus sp. A (346-U1425B-47H1-91-93 cm); 6-7: Spongodiscus cauletti group Kamikuri (6: 346-U1425B-47H1-91-93
cm; 7: 346-U1425B-34H4-46-48 cm); 8, 12-13, 15-19: Flustrella sp. A (8. 346-U1425B-47H1-91-93 cm; 12,15-18. 346-U1425B34H4-46-48 cm); 9: Spongopyle osculosa Dreyer (346-U1425B-28H3-147-149 cm); 10-11: Flustrella spp. (young forms) (10.
346-U1425B-28H3-147-149 cm; 11. 346-U1425B-47H1-91-93 cm); 14: Spongodiscus sp. A (14: 346-U1425B-34H4-46-48
cm); 20-21: Spongodiscidae juveniles spp. (346-U1425B-47H1-91-93 cm); 22-27: Stylodictya tenuispina Jørgensen group(23-24. 346-U1425B-34H4-46-48 cm; 22, 25-27. 346-U1425B-47H1-91-93 cm).
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Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Plate 3

1: Tetrapyle cf. circularis Haeckel (346-U1425B-34H4-46-48 cm); 2: Tetrapyle cf. fruticosa (Tan and Chen) (346-U1425B-34H4-46-48
cm); 3-4, 8: Phorticium cf. polycladum Tan and Tchang (3, 8. 346-U1425B-34H4-46-48 cm; 4. 346-U1425B-28H3-147-149 cm);
5-6, 11, 14-18: Prunulum coccymelia Haekcel group (5,18. 346-U1425B-34H4-46-48 cm; 6,16,17. 346-U1425B-47H1-91-93 cm;
11. 346-U1425B-28H3-147-149 cm; 14. 346-U1425B-47H1-91-93 cm; 15. 346-U1425B-28H3-147-149 cm); 7: Phorticium sp.
A (346-U1425B-34H4-46-48 cm); 9-10, 12-13: Phorticium aff. scitulum Zhang and Suzuki (9,10,12. 346-U1425B-34H4-46-48
cm; 13. 346-U1425B-47H1-91-93 cm); 19-26: Sphaerolarnacillium sp. A (346-U1425B-34H4-46-48 cm).
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Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Plate 41-4: Larcopyle aff. polyacantha (Campbell and Clark) (346-U1425B-47H1-91-93 cm); 5-14: Larcopyle weddellium Lazarus,
Faust and Popova-Goll group (346-U1425B-47H1-91-93 cm); 15: Larcopyle sp. A (346-U1425B-34H4-46-48 cm); 16-17:
Larcopyle labyrinthusa Lazarus, Faust and Popova-Goll (16. 346-U1425B-34H4-46-48 cm; 17. 346-U1425B-47H1-91-93cm); 18: Larcopyle sp. B (346-U1425B-34H4-46-48 cm); 19: Lithelius sp. A (346-U1425B-34H4-46-48 cm); 20: Lithelius cf.
nautiloides (Popofsky) (346-U1425B-47H1-91-93 cm); 21: Lithelius sp. B (346-U1425B-47H1-91-93 cm); 22-23: Lithelius
sp. C (346-U1425B-34H4-46-48 cm).

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Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Plate 5

1-4, 7: Lihelius barbatus Motoyama (346-U1425B-28H3-147-149 cm). 5-6, 7, 8-11: Spiremaria cf. decens Kozlova(346-U1425B-28H3-147-149 cm). 12, 16-17: Lithelidae gen et sp. indet (12. 346-U1425B-28H3-147-149 cm; 16-17.
346-U1425B-47H1-91-93 cm); 13-15: Lithelius aff. spiralis group (Ehrenberg) (13, 14. 346-U1425B-47H1-91-93 cm; 15.
346-U1425B-34H4-46-48 cm); 18-19: Phacodiscus aff. calvertense (Martin) (346-U1425B-47H1-91-93 cm); 20-21: Lithelius
klingi Kamikuri (346-U1425B-47H1-91-93 cm).

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Plate 6

1: Dendrospyris sp. A (346-U1425B-34H4-46-48 cm); 2-3: Dendrospyris sp. B (2. 346-U1425B-34H4-46-48 cm; 3.
346-U1425B-47H1-91-93 cm); 4, 6: Dendrospyris sp. C (346-U1425B-47H1-91-93 cm); 5: Dendrospyris sp. D (346-U1425B47H1-91-93 cm); 7: Undet. Triospyridae (346-U1425B-34H4-46-48 cm); 8: Dendrospyris sp. E (346-U1425B-47H1-91-93cm); 9-10: Dendrospyris cf. eurus Kamikuri (346-U1425B-47H1-91-93 cm); 11-12: Zygocircus archicircus Popofsky (11-12.
346-U1425B-34H4-46-48 cm); 13: Zygocircus? sp. A (346-U1425B-34H4-46-48 cm); 14-16: Steganocubus sp. A (346-U1425B30HCC-12-17 cm; 13. 346-U1425D-29H1-45-47 cm); 17-19: Peridium sphaerum Funakawa (346-U1425B-28H3-147-149 cm);
20: Steganocubus? sp. (346-U1425B-28H3-147-149 cm); 21-22: Cryptogyrus aff. trachylobus Sugiyama (21. 346-U1425B47H1-91-93 cm; 22, 346-U1425B-34H4-46-48 cm); 23: Lophophaenidae gen. et sp. indet. (346-U1425B-34H4-46-48 cm);
24-27: Botryopera? gibbera Renaudie and Lazarus (346-U1425B-47H1-91-93 cm); 28: Pseudodictyophimus cf. elegans Dogiel
and Reshetnyak (346-U1425B-28H3-147-149 cm); 29: Pseudodictyophimus sp. A (346-U1425B-34H4-46-48 cm); 30-31:
Siphocampe arachnea/lineata (Ehrenberg) group (346-U1425B-34H4-46-48 cm); 32-33: Botryostrobus bramlettei Campbell
and Clark) group (346-U1425B-47H1-91-93 cm); 34-35: Botryocampe aff. robusta (Kruglikova) (346-U1425B-30HCC-12-17cm); 36: Botryopera? daleki Renaudie and Lazarus (346-U1425B-28H3-147-149 cm).
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Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Plate 7

1-14: Cycladophora nakasekoi Motoyama (346-U1425B-47H1-91-93 cm); 15-22: Cycladophora aff. nakasekoi Motoyama(346-U1425B-47H1-91-93 cm); 23: Cycladophora cf. sphaeris (Popova) (346-U1425B-34H4-46-48 cm); 24-26: Cycladophorasphaeris (Popova) (346-U1425B-28H3-147-149 cm); 27-28: Cycladophora cosma cosma Lombari and Lazarus (346-U1425B47H1-91-93 cm); 29: Cycladophora aff. cornuta (Bailey) (346-U1425B-47H1-91-93 cm).
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Bulletin of the Geological Survey of Japan, vol.70 (1/2), 2019

Plate 8

1: Stichocorys delmontensis (Campbell and Clark) (346-U1425B-34H4-46-48 cm); 2-8, 11: Stichocorys peregrina (Riedel)"equatorial form" (346-U1425B-34H4-46-48 cm); 9-10, 12-21: Stichocorys peregrina (Riedel) "North Pacific form"(); 22-23:
Stichocorys sp. A (346-U1425B-34H4-46-48 cm).

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Late Miocene radiolarians of the Japan Sea (Matsuzaki and Itaki)

Plate 91: Lychnocanoma magnacornuta Sakai (346-U1425B-51HCC-24-29 cm); 2: Lychnocanoma parallelipes Motoyama(346-U1425D-29H1-45-47 cm); 3-4: Lipmanella redondoensis (Campbell & Clark) (346-U1425B-47H1-91-93 cm);
5-6: Cinclopyramis quadrata (Haeckel) comb. nov. (346-U1425B-47H1-91-93 cm); 7-8: Cyrtolagena cuspidata (Bailey)(346-U1425B-47H1-91-93 cm); 9-12: Cornutella bimarginatus (Haeckel) (9. 346-U1425B-28H3-147-149 cm; 10-12.
346-U1425B-47H1-91-93 cm); 13-15: Cornutella trochus Ehrenberg (346-U1425B-47H1-91-93 cm); 16-21: Carpocanarium
papillosum (Ehrenberg) group (346-U1425B-47H1-91-93 cm).

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