Bulletin of the Geological Survey of Japan, vol. 70 (1/2), p. 163–194, 2019

Notes and Comments

Middle to late Miocene radiolarians from ODP Site 1021
in the eastern North PacificShin-ichi Kamikuri1,*
Shin-ichi Kamikuri (2019) Middle to late Miocene radiolarians from ODP Site 1021 in the eastern North
Pacific. Bull. Geol. Surv. Japan, vol. 70 (1/2), p. 163–194, 1 figure, 24 plates.
Abstract: The purpose of this study is to present microphotgraphs of all the encountered taxa of the
middle to late Miocene age from Ocean Drilling Program (ODP) Site 1021 in the eastern North Pacific inorder to analyze the species diversity of radiolarians. Totally 149 species or species groups of radiolarians
were identified from Site 1021 in the eastern North Pacific. Micro-photographs have been illustrated in
the 24 plates, and a new species, Lychnocanoma californica, is described.
Keywords: eastern North Pacific, Miocene, radiolaria, new species

1. Introduction
The California Current system is one of the most
biologically productive ecosystems in the world’s oceanbecause they benefit from nutrient-rich coastal upwelling.
Ocean Drilling Program (ODP) Leg 167 was designed
to study the evolution of the California Current system
and associated upwelling systems from the middle
Miocene to the Quaternary (Lyle et al., 1997), and thirteensites were drilled from about 30°
N to 42°
N along theCalifornia continental margin in the eastern North Pacific
Ocean. Of these thirteen sites, Site 1021 was drilled for
paleoceanographic reconstruction of the northern regionof the area inﬂuenced by the California Current during the
Neogene. LaRiviere et al. (2012) estimated quantitative
geochemical sea surface temperature since the late middle
Miocene from Site 1021 in the eastern North Pacific.
Barron et al. (2002) presented weight percent opal
records since the late middle Miocene from Site 1021, andindicated that a dramatic decline occurred at about 7.6 Ma.
Radiolarians, which is one of the siliceous microfossil
group, were found in the sediment recovered from Site
1021, however its preservation of the fauna changed fromage to age (Lyle et al., 1997; Kamikuri, 2017). Sediments
older than the latest Miocene was relatively abundantin radiolarians, of which preservation was good. The
sediments from the middle to upper Miocene are suitable
for studies of taxonomy, biostratigraphy and species
diversity on radiolarians.
The most important taxonomic studies of the middle

1*

to upper Miocene in the eastern North Pacific is that ofCampbell and Clark (1944). The taxonomic studies werebased on siliceous sediments of onshore California. After
that, several biostratigaraphic studies of radiolarians wereconductive in the eastern North Pacific (Rowell, 1981;
Poore et al., 1981; Weaver et al., 1981; Perez-Guzman,
1985; Perez-Guzman and Casey, 1986). Kamikuri (2017)
studied biostratigraphic distribution of selected radiolarians
from ODP Site 1021 in the eastern North Pacific. The
purpose of this study is to present microphotgraphs of all
the encountered taxa of the middle to late Miocene age
from Site 1021 in the eastern North Pacific in order toanalyze the species diversity of radiolarians.

2. Material and methods
Site 1021 was drilled at a water depth of 4211.5 m(39°
5.248’N, 127°
46.985’W) in the eastern North Pacific(Fig. 1). The lithology of the middle to upper Miocene ofthis site is characterized by clay and diatom ooze withwell-preserved radiolarians (Lyle et al., 1997). A total of 49
sediment samples from 1021B-22X-1, 20-22 cm to 33X6, 20-22 cm (210.32 to 308.21 meters composite depth
below seaﬂoor; 7.50 to 12.83 Ma) were examined in thisstudy (Plates 1 to 24). Sample preparation for microscopic
examination followed the standard techniques (Sanfilippo
et al., 1985). Sediment samples were treated with H2O2
and HCl solution. The residues were sieved with 63 µm.
An optical microscope was used for observation andphotomicrographic work.

Faculty of Education, Ibaraki University, Bunkyo 2-1-1, Ibaraki 310-8512, Japan
Corresponding author: S. Kamikuri, Email: shin-ichi.kamikuri.
@vc.ibaraki.ac.jp− 163 −

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

150˚W

120˚W

90˚W

60˚N

Site 1021
30˚N

N. PacificFig. 1 Location map of ODP Site 1021 in the eastern North
Pacific.

0˚

3. Radiolarian
diversity
Fig. species
1 Kamikuri
Totally 149 species or species groups of radiolarians
were identified from Site 1021 in the eastern North
Pacific. Micro-photographs are illustrated in the 24 plates
including a new species, Lychnocanoma californica.

4. Taxonomic Notes
Genus Lychnocanoma Haeckel 1887, emend.
Foreman 1973
Lychnocanoma californica Kamikuri n. sp.
Plate 1, figs. 6-11.
Lychanocanoma nipponica type B. Kamikuri 2017, figs. 2a, b.
Holotype: MPC-42136; ODP Hole 1021B-26X-4, 70-72
cm, D42/0. Plate 1, figs 8a, b. Holotype is on depositin the micropaleontological reference collection of the
Natural Science Museum, Tokyo, Japan.
Description: Cephalis moderate in size with a few small
subcircular pores. Apical horn, simple unbladed andits length being 0.5 times to twice as long as cephalicdiameter. Collar stricture distinct. Thorax hemispherical,
usually thick-walled with a relatively smoothed surface
and being subcircular pores aligned longitudinally.
Thoracic pores, medium and regular in size, about
12-16 pores on a half circumference. Three feet, threebladed, robust, straight or slightly curved with outward
convexity. Feet have usually one or two proximal pores.

In some specimens, meshwork on the inner margin of
the feet.
Dimensions (based on ten specimens): Length of apicalhorn: up to 40 µm; cephalic diameter: 20-30 µm; lengthof thorax: 50-70 µm; width of thorax: 85-120 µm; lengthof foot: up to 170 µm.
Distinguishing characters: Lychnocanoma californica isclosely related to Lychnocanoma parallelipes Motoyama.
Lychnocanoma californica differs from L. parallelipes
by a relatively thin thorax with a smooth surface, and ashorter and thin apical horn. Lychnocanoma californica
can be distinguished from Lychnocanoma nipponica
Nakaseko and Lychnocanoma magnacornuta Sakai by
its parallel or slightly convergent feet.
Occurrence: Lychnocanoma californica (=Lychnocanoma
nipponica type B in original paper) occurred from 9.4 to
6.2 Ma in the late Miocene (Kamikuri, 2017).
Genus Actinomma Haeckel 1861a,
sensu Burridge et al. 2014
Actinomma hootsi (Campbell and Clark)
Plate 10, figs. 1a-4b, plate 16, figs. 8a, b.
Hexacontium hootsi Campbell and Clark 1944, p. 14, pl. 2, fig. 5.
Remarks: I changed the genus name to Actinomma,
because this species characterized by three cortical shells
with eight to ten unbranched spines.

− 164 −

Actinomma robusta (Kling)Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

pl. 1, figs. 6-10.

Plate 12, figs. 4a-8b.
Sphaeropyle robusta Kling 1973, p. 634, pl. 1, figs. 11,
12, pl. 9, figs. 9-13, pl. 13, figs. 1-5; Morley and Nigrini
1995, p. 81, pl. 1, figs. 6, 7.

Remarks: I changed genus name to Rhizosphaera, because
this species is similar to Rhizosphaera antarctica(Haeckel) in Dumitrica (2017).

Remarks: I changed the genus name to Actinomma,
because this species is similar to Actinomma langii(Dreyer) in Burridge et al. (2014).

5. Species list

Genus Cinclopyramis Haeckel 1879,
sensu Suzuki et al. 2009
Cinclopyramis circumtexta (Haeckel) group
Plate 6, figs. 13, 14, 17.
Peripyramis circumtexta Haeckel 1887, p. 1162, pl. 54, fig. 5.
Peripyramis circumtexta Haeckel group in Petrushevskaya
1975, p. 587, pl. 13, fig. 29, pl. 44, figs. 5, 6.
Remarks: I changed the genus name to Cinclopyramis,
because Peripyramis is junior synonym of Cinclopyramis(Suzuki et al., 2009).
Genus Cycladophora Ehrenberg 1872, emend.
Lombari and Lazarus 1988
Cycladophora klingi Lombari and Lazarus
Plate 1, figs. 3a, b.
Cycladophora bicornis klingi Lombari and Lazarus 1988,
p. 108, pl. 4, figs. 1-5.
Remarks: Cycladophora klingi was described originallyas a subspecies of Cycladophora bicornis by Lombariand Lazarus (1988). I have raised this taxon to species
rank, because this species is distinguished from othercycladophorids by its small compact shape and lower
thorax skirt.
Genus Lamprotripus Haeckel 1882
Lamprotripus splendens (Campbell and Clark)
Plate 2, fig. 6
Pterocorys (Pterocyrtidium) splendens Campbell and
Clark 1944, p. 46, pl. 6, figs. 16, 19, 20.
Dictyophimus splendens (Campbell and Clark) in Morley
and Nigrini 1995, p. 79, pl. 7, figs. 3, 4.
Remarks: I changed genus name to Lamprotripus, because
this species is similar to Lamprotripus cortina (Haeckel)
and L. hirundo (Haeckel) in Matsuzaki et al. (2015).
Genus Rhizosphaera Haeckel 1861b,
sensu Dumitrica 2017
Rhizosphaera churchi (Campbell and Clark) group
Plate 8, figs. 1-8.
Plegmosphaera churchi Campbell and Clark 1944, p. 10,

Amphistylus angelinus (Campbell and Clark) in Takemura
1992, p. 741, pl. 1, figs. 8, 9. [Plate 14, fig. 13.]
Amphymenium amphistylium Haeckel in Morley and
Nigrini 1995, p. 78, pl. 1, figs. 8, 9. [Plate 19, fig. 4.]
Anthocyrtidium sp. A: This study. [Plate 3, figs. 9, 10.]
Anthocyrtidium sp. B: This study. [Plate 3, fig. 11.]Axoprunum bispiculum (Popofsky) in Takemura 1992, p.
741, pl. 1, figs. 1, 2. [Plate 14, fig. 11.]
Botryostrobus bramlettei (Campbell and Clark) in Nigrini
and Lombari 1984, p. N175, pl. 31, figs. 2a–2c. [Plate
1, fig. 12.]
Calocycletta caepa Moore 1972, p. 150, pl. 2, figs. 4–7.
[Plate 3, fig. 1.]
Calocycletta sp. A: This study. [Plate 3, fig. 5.]
Calocycletta sp. B: This study. [Plate 3, fig. 4.]
Calocycletta sp. C: This study. [Plate 3, figs. 2, 3.]
Carpocanium favosa (Haeckel): Carpocanistrum favosum(Haeckel) in Takahashi 1991, p. 131, pl. 45, fig. 8:
Carpocanium spp. in O’
Connor 1997, p. 111, pl. 3,
figs. 18–20. [Plate 1, fig. 15.]
Cenosphaera jenkinsi Campbell and Clark group:
Cenosphaera jenkinsi Campbell and Clark 1944, p.
9, pl. 1, figs. 2–4. [Plate 15, figs. 1–11; Plate 16, figs.
6, 7.]
Ceratocyrtis aff. mashae Bjørklund in Matsuzaki et al.
2015, p. 46, fig. 7.24. [Plate 5, figs. 10, 11.]
Ceratocyrtis sp. A: This study. [Plate 5, fig. 12.]
Ceratocyrtis sp. C: This study. [Plate 5, fig. 13.]
Cinclopyramis murrayana Haeckel in Matsuzaki et al.
2015, p. 58, figs. 9.19, 9. 20; Bathropyramis woodringi
Campbell and Clark 1944, p. 39, pl. 5, figs. 21, 22.
[Plate 6, fig. 7.]
Circodiscus circularis (Clark and Campbell) in Jackett
et al., 2008, p. 50, pl. 4, figs. 10, 12; Porodiscus
circularis Clark and Campbell 1942, p. 42, pl. 2, figs.
2, 6, 10. [Plate 20, figs. 1–4.]
Collosphaera glebulenta Bjørklund and Goll 1979, p.
1316, pl. 2, figs. 9–25. [Plate 17, figs. 1–6.]
Collosphaera reynoldsi Kamikuri 2010, p. 97, pl. 3, figs.
18-25. [Plate 17, fig. 7.]
Collosphaera sp. A: This study. [Plate 17, fig. 9.]
Collosphaera sp. B: This study. [Plate 17, fig. 8.]
Cornutella paloverdensis Campbell and Clark 1944, p. 40,
pl. 5, figs. 17, 20, 24, 25. [Plate 6, fig. 3.]
Cornutella profunda Ehrenberg in Nigrini and Lombari
1984, p. N93, pl. 22, fig. 1. [Plate 6, fig. 15.]
Cromydruppocarpus esterae Campbell and Clark 1944, p.
20, pl. 2, figs. 26–28. [Plate 14, figs. 4–6.]
Cycladophora bicornis (Popofsky) in Matsuzaki et al.

− 165 −

Bulletin of the Geological Survey of Japan, vol. 70 (1/2), 20192015, p. 63, figs. 8.19–8. 22; Not Cycladophorabicornis bicornis (Popofsky) in Lombari and Lazarus
1988, p. 106, pl. 5, figs. 9–12. [Plate 1, fig. 4.]
Cycladophora cabrilloensis (Campbell and Clark):
Clathrocyclas cabrilloensis Campbell and Clark 1944,
p. 48, pl. 7, fig. 1 (only); Cycladophora cabrilloensis
cabrilloensis (Campbell and Clark) in Lombari and
Lazarus 1988, p. 118, pl. 7, figs. 1–12. [Plate 1, fig. 1.]
Cycladophora cosma Lombari and Lazarus: Cycladophoracosma cosma Lombari and Lazarus 1988, p. 104, pl.
1, figs. 1-6; Cycladophora cosma irregularis Lombariand Lazarus 1988, p. 105, pl. 1, figs. 7–12. [Plate 1,
fig. 2.]Cycladophora sphaeris (Popova): Spuroclathrocylas
sphaeris Popova 1989, p. 73, pl. 11, fig. 17, pl. 12,
fig. 3; Cycladophora sakaii Motoyama 1996, p. 246,
pl. 4, figs. 4a–6b; Cycladophora sphaeris (Popova) in
Kamikuri 2017, fig. 8.5. [Plate 1, fig. 5.]
Cyrtocapsella cornuta Haeckel in Sakai 1980, p. 709, pl.
8, figs. 8a, 8b. [Plate 5, fig. 4.]
Cyrtocapsella japonica (Nakaseko) in Sakai 1980, p. 709,
pl. 8, figs. 7a, 7b. [Plate 5, figs. 8, 9.]Cyrtocapsella tetrapera Haeckel in Sakai 1980, p. 709,
pl. 8, figs. 5, 6. [Plate 5, fig. 5.]
Cyrtolagena sp. A: This study. [Plate 6, fig. 16.]
Dendrospyris aff. bursa (Sanfilippo and Riedel): This
study. [Plate 7, figs. 12, 13.]
Dendrospyris sp. A: This study. [Plate 7, figs. 3-5.]
Dendrospyris sp. B: This study. [Plate 7, fig. 6.]
Dendrospyris sp. C: This study. [Plate 7, fig. 8.]
Dendrospyris sp. D: This study. [Plate 7, fig. 9.]
Dendrospyris sp. E: This study. [Plate 7, fig. 11.]
Dendrospyris sp. F: This study. [Plate 7, fig. 14.]
Diartus hughesi (Campbell and Clark) in Sanfilippo et al.
1985, p. 655. Fig. 8.11. [Plate 19, figs. 20, 21.]Dictyocoryne malagaense (Campbell and Clark) group:
Rhopalodictyum malagaense Campbell and Clark
1944, p. 29, pl. 4, figs. 4, 5. [Plate 19, figs. 1, 2.]
Dictyocoryne sp. A: This study. [Plate 19, fig. 3.]
Dictyophimus sp. A: This study. [Plate 5, fig. 16.]
Didymocyrtis antepenultima (Riede and Sanfilippo) in
Sanfilippo et al. 1985, p. 657, fig. 8.6. [Plate 19, figs.
18, 19.]
Didymocyrtis laticonus (Riedel) in Sanfilippo et al. 1985,
p. 658, figs. 8.5a, 8.5b. [Plate 19, figs. 16, 17.]
Didymocyrtis penultima (Riede and Sanfilippo) in
Sanfilippo et al. 1985, p. 658, figs. 8.7a, 8.7b. [Plate
19, figs. 14, 15.]
Didymocyrtis sp. C: This study. [Plate 19, figs. 22, 23.]
Didymocyrtis sp. D: This study. [Plate 19, figs. 24, 25.]
Druppatractus hastatus Blueford 1982, p. 206, pl. 6, figs.
3, 4. [Plate 14, fig. 7.]
Eucyrtidium calvertense Martin in Morley and Nigrini
1995, p. 82, pl. 4, fig. 8. [Plate 4, fig. 8.]
Eucyrtidium cienkowskii Haeckel group in Sakai 1980, p.
710, pl. 7, figs. 8a–10. [Plate 4, figs. 9–11.]
Eucyrtidium hexagonatum Haeckel in Nigrini and

Lombari 1984, p. N115, pl. 23, fig. 8. [Plate 4, fig. 7.]
Eucyrtidium inflatum Kling 1973, p. 636, pl. 11, figs. 7,
8, pl. 15, figs. 7-10. [Plate 4, fig. 13; Plate 5, fig. 15.]
Eucyrtidium sp. D: This study. [Plate 5, fig. 14.]
Eucyrtidium sp. E: This study. [Plate 4, fig. 12.]
Eucyrtidium sp. G: This study. [Plate 4, fig. 14.]
Excentrodiscus japonicus (Nakaseko and Nishimura) in
Kamikuri 2010, p. 86, pl. 2, figs. 2a–3b, 5a–6b, 8a–9b,
11a, 11b, 13a–14b, pl. 4, figs. 19a–19c. [Plate 10,
figs. 5–7.]
Gondwanaria campanulaeformis (Campbell and Clark),
Funakawa 2000, p. 100, pl. 1, figs. 1a–1d, pl. 7, figs.
1a, 1b, text-fig. 4. [Plate 6, fig. 2.]
Haliommetta miocenica (Campbell and Clark) group in
Petrushevskaya and Kozlova 1972, p. 517, pl. 9, figs.
8, 9. [Plate 9, figs. 1–9.]
Heliodiscus sp. A: This study. [Plate 24, fig. 9.]
Hexacontium aff. arachnoidale Hollande and Enjumet:
This study. [Plate 11, figs. 4, 5.]Hexacontium minerva Kamikuri 2010, p. 97, pl. 3, figs.
12a–14b, 16a–17b. [Plate 11, figs. 6–9.]
Hexacontium sp. A: This study. [Plate 11, fig. 1.]
Hexacontium sp. B: This study. [Plate 11, figs. 2, 3.]
Hexacontium sp. E: This study. [Plate 12, fig. 1.]
Hexastylus aculeata (Campbell and Clark): Staurolonche
aculeate Campbell and Clark 1944, p. 13, pl. 2, figs.
2, 3. [Plate 12, fig. 3.]
Hexastylus sp. A: This study. [Plate 12, fig. 2.]
Lamprocyclas hannai (Campbell and Clark): Calocyclas
hannai Campbell and Clark 1944, p. 48, pl. 6, figs.
21, 22; Lamprocyclas hannai (Campbell and Clark)
in Sanfilippo et al. 1985, fig. 29.8. [Plate 4, figs. 1–6.]
Lamprocyclas sp. C: This study. [Plate 3, figs. 12, 13.]
Lamprotripus cortina (Haeckel) in Matsuzaki et al. 2015,
p. 64, fig. 8.5. [Plate 2, fig. 4.]
Larcopyle aff. pylomaticus (Riedel): This study. [Plate
18, fig. 5.]
Larcopyle buetschlii Dreyer in Matsuzaki et al. 2015, p.
33, fig. 6.21–6.28. [Plate 18, figs. 18–22.]
Larcopyle polyacantha ( Campbell and Clark ) :Larnacantha polyacantha Campbell and Clark 1944,
p. 30, pl. 5, figs. 4-7. [Plate 18, figs. 7-17.]
Larcopyle sp. A: This study. [Plate 18, fig. 6.]
Larcospira moschkovskii Kruglikova in Nigrini and
Lombari 1984, p. S91, pl. 13, figs. 2a, 2b. [Plate 20,
fig. 17; Plate 22, fig. 8.]
Larcospira quadrangula Haeckel group in Nigrini and
Lombari 1984, p. S93, pl. 13, figs. 3a-3c. [Plate 18,
fig. 3; Plate 22, figs. 9, 10.]
Liosphaera hexagonia Haeckel in Takahashi and Honjo
1981, p. 146, pl. 1, fig. 23. [Plate 13, fig. 16.]
Lipmanella hister (Petrushevskaya) in Sugiyama andFurutani 1992, p. 209, pl. 13, figs. 7, 8. [Plate 6, fig.
11.]
Lipmanella redondoensis (Campbell and Clark) inFunakawa 2000, p. 108, pl. 4, figs. 2a–3c, pl. 7, figs.
6a–6c, text-fig. 8. [Plate 6, figs. 8–10.]− 166 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Lithelius aff. elliptica (Ehrenberg): This study. [Plate 18,
fig. 4.]
Lithelius klingi Kamikuri 2010, p. 95, pl. 4, figs. 9-14.
[Plate 18, fig. 1.]
Lithelius minor Jørgensen group: Lithelius minor
Jørgensen in Nigrini and Moore 1979, p. S135, pl.
17, figs. 3-4b. [Plate 18, fig. 2.]
Lithomelissa cf. ultima Caulet: Lithomelissa ultima Caulet
1979, p. 129, pl. 1, figs. 2, 3. [Plate 6, fig. 4.]
Lithomelissa sp. A: This study. [Plate 6, fig. 5.]
Lithomelissa sp. B: This study. [Plate 6, fig. 6.]
Lithopera neotera Sanfilippo and Riedel in Sanfilippo etal. 1985, p. 675, figs. 16.5a-16.4c. [Plate 5, fig. 3.]
Lithopera renzae Sanfilippo and Riedel in Sanfilippo et al.
1985, p. 675, figs. 16.4a, 16.5b. [Plate 5, figs. 1, 2.]Lophoconus bihastatus Clark and Campbell 1945, p. 47,
pl. 6, fig. 15. [Plate 3, fig. 6.]
Lophocyrtis aspera (Ehrenberg) in Sanfilippo and Caulet
1998, p. 14, pl. 3A, figs. 5-10, pl. 3B, figs. 1, 2, 5-9,
pl. 6, figs. 6-8. [Plate 6, fig. 1.]
Lophospyris laventaensis (Campbell and Clark ):Ceratospyris (Lophospyris) laventaensis Campbell
and Clark 1944, p. 36, pl. 5, fig. 15. [Plate 7, figs. 1, 2.]
Lychnocanoma magnacornuta Sakai in Motoyama 1996,
p. 248, pl. 5, figs. 10a-11. [Plate 2, fig. 5.]
Lychnocanoma nipponica (Nakaseko): Lychnocanium
nipponicum Nakaseko in Shilov 1995, p. 109, pl.
3, figs. 4a, 4b; Lychnocanoma nipponica nipponica(Nakaseko) in Morley and Nigrini 1995, p. 81, pl.
5, figs. 4, 5; Lychnocanoma nipponica (Nakaseko)
type A in Kamikuri 2017, pl. 6, figs. 1a, 1b. [Plate 2,
figs. 1, 2.]
Lychnodictyum aff. audax Riedel: This study. [Plate 2,
fig. 3.]
Perichlamydium scutaeforme Campbell and Clark 1944,
p. 24, pl. 3, figs. 14-16. [Plate, 20 figs. 10-15; Plate
23, figs. 9-12.]
Perichlamydium sp. K: This study. [Plate 24, figs. 7, 8.]
Perichlamydium sp. P: This study. [Plate 20, fig. 16.]
Phormospyris stabilis (Goll): Phormospyris stabilis
stabilis (Goll) in Nigrini and Lombari 1984, p. N59,
pl. 19, fig. 7. [Plate 7, fig. 7.]
Phormostichoartus fistula Nigrini in Nigrini and Lombari
1984, p. N183, pl. 31, figs. 6a-6c. [Plate 1, fig. 13.]
Phorticium clevei (Jørgensen) in Matsuzaki et al. 2015, p.
32, figs. 6.9, 6.10. [Plate 19, figs. 11-13.]
Phorticium sp. A: This study. [Plate 19, figs. 8-10.]
Polysolenia murrayana (Haeckel) in Nigrini and Moore
1979, p. S17, pl. 2, figs. 4a, 4b. [Plate 17, fig. 11.]
Polysolenia pseudarktios (Caulet): Acrosphaera pseudarktios
Caulet 1986, p. 226, pl. 1, fig. 8. [Plate 17, fig. 10.]Saturnalis circularis Haeckel in Takahashi 1991, p. 78,
pl. 15, figs. 15-18. [Plate 13, fig. 11.]
Spirocyrtis subscalaris Nigrini in Nigrini and Lombari
1984, p. N199, pl. 32, figs. 7a, 7b. [Plate 1, fig. 14.]
Spongaster sp. A: This study. [Plate 21, fig. 13.]
Spongodiscus cauleti Kamikuri 2010, p. 94, pl. 4, figs.

1-4. [Plate 24, figs. 5, 6.]
Spongodiscus resurgens Ehrenberg in Petrushevskaya andKozlova 1972, p. 528, pl. 21, fig. 5. [Plate 21, figs.
1-12.]
Spongodiscus sp. D: This study. [Plate 21, fig. 14.]
Spongopyle osculosa Dreyer in Nigrini and Moore 1979,
p. S115, pl. 15, fig. 1. [Plate 22, figs. 5-7.]
Spongotrochus sol Campbell and Clark 1944, p. 28, pl. 4,
figs. 7, 9-11. [Plate 24, figs. 1, 2.]
Spongotrochus sp. B: This study. [Plate 22, fig. 1.]
Spongotrochus sp. C: This study. [Plate 22, figs. 2-4.]
Spongotrochus sp. Z: This study. [Plate 24, figs. 3, 4.]Spongurus cylindricus Haeckel in Takahashi 1991, p. 85,
pl. 17, figs. 6-9. [Plate 19, fig. 5.]
Stichocorys delmontensis (Campbell and Clark) in
Kamikuri 2012, p. 24, pl. 1, figs. 1-9, pl. 3, figs. 1-6.
[Plate 5, fig. 7.]
Stichocorys peregrina (Riedel) in Kamikuri 2012, p. 25,
pl. 2, figs. 1-9, pl. 3, figs. 7-12. [Plate 5, fig. 6.]
Stylatractus neptunus Haeckel in Petrushevskaya andKozlova 1972, p. 520, pl. 11, fig. 11. [Plate 16, figs.
3-5.]Stylatractus santaeannae (Campbell and Clark) in
Petrushevskaya and Kozlova 1972, p. 520, pl. 11,
fig. 10. [Plate 16, fig. 9.]
Stylatractus universus Hays in Morley and Nigrini 1995,
p. 82, pl. 2, fig. 3. [Plate 14, fig. 12.]Stylodictya ornata Campbell and Clark 1944, p. 26, pl. 3,
fig. 20. [Plate 23, figs. 1-6.]Stylodictya tenuispina Jørgensen 1905, p. 118, pl. 10, fig.
39. [Plate 23, figs. 7, 8.]
Stylodictya sp. A: This study. [Plate 20, figs. 5-9.]Stylosphaera radiosa Ehrenberg in Petrushevskaya
and Kozlova 1972, p. 520; Amphisphaera radiosa(Ehrenberg) group in Petrushevskaya 1975, p. 570,
pl. 2, figs. 18-20; Lithatractus santaennae pusillus
Campbell and Clark 1944, p. 19, pl. 2, figs. 23-25.
[Plate 14, figs. 1-3.]Stylosphaera timmsi (Campbell and Clark): Stylosphaera(?) timmsi (Campbell and Clark) in Sugiyama andFurutani 1992, p. 203, pl. 12, figs. 3, 4, pl. 15, figs. 1,
2. [Plate 14, figs. 8-10.]
Styptosphaera spumacea Haeckel in Vitukhin 1993, pl.
27, fig. 6, pl. 28, fig. 5. [Plate 16, figs. 1, 2.]Tetrapyle circularis/fruticosa group: Tetrapyle circularis
Haeckel in Zhang and Suzuki, 2017, p. 15, figs. 8.18.15, 9.1-9.9; Tetrapyle fruticosa (Tan and Chen)in Zhang and Suzuki 2017, p. 18, figs. 10.1-10.4;
Tetrapyle spp. (juvenile form) in Zhang and Suzuki
2017, p. 19, figs. 11.1-11.18. [Plate 19, figs. 6, 7.]
Thecosphaera dedoensis Nakaseko in Motoyama 1996,
pl. 2, fig. 2. [Plate 13, figs. 1-8.]
Thecosphaera sp. A: This study. [Plate 13, figs. 9, 10.]
Thecosphaera sp. B: This study. [Plate 13, figs. 12-15.]
Theocorys perforalvus O’
Connor 1997, p. 86, pl. 4, figs.
9-12, pl. 10, figs. 9-14, pl. 11, fig. 6. [Plate 6, fig. 12.]
Thecorythium sp. A: This study. [Plate 3, fig. 7.]− 167 −

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

Tholospyris kantiana (Haeckel) in Nigrini and Lombari
1984, p. N71, pl. 20, figs. 2a–2c. [Plate 7, fig. 10.]
Acknowledgement
The authors are grateful to Dr. Kenji M. Matsuzaki forreviewing the manuscript. Samples were provided by the
Ocean Drilling Program (ODP).
This work was also supported in part by the Japan
Society for the Promotion of Science (JSPS) KAKENHI
Grant Number 15K17780 (S. Kamikuri).

References
Barron, J. A., Lyle, M. and Koizumi, I. (2002) Late Miocene
and early Pliocene biosiliceous sedimentation along
the California margin. Revista Mexicana de Ciencias
Geologicas, 19, 161–169.
Bjørklund, K. R. and Goll, R. M. (1979) Internal
skeletal structures of Collosphaera and Trisolenia:
a case of repetitive evolution in the Collosphaeridae(Radiolaria). Jour. Paleontol., 53, 1293–1326.
Blueford, R. (1982) Miocene actinommid Radiolaria
from the equatorial Pacific. Micropaleontology, 28,
189–213.
Burridge, A. K., Bjørklund, K. R., Kruglikova, S. B.
and Hammer, Ø. (2014) Inter- and intraspecificmorphological variation of four shelled Actinomma
taxa (Radiolaria) in polar and subpolar regions.
Marine Micropaleontol., 110, p. 50–71.
Campbell, A. S. and Clark, B. L. (1944) Miocene
radiolarian faunas from southern California. Geol.
Soc. Amer., Spec. Pap., 51, 1–76.
Caulet, J. -P. (1979) Les Radiolaires des boues superficielles
de la Méditerranée. Bulletin du Muséum Nationald’Histoire Naturelle, Série 3, 39, 217–287.
Caulet, J. -P. (1986) Radiolarians from the southwest
Pacific. In Kennett, J. P., von der Borch, C. C. etal., eds., Init. Rep. Deep Sea Drilling Project, 90,
Washington, D. C.: U.S. Government Printing Office,835–861.
Clark, B. L. and Campbell, A. S. (1942) Eocene radiolarianfaunas from the Mt. Diablo area, California. Geol.
Soc. Amer., Spec. Pap., 39, 1–112.
Clark, B. L. and Campbell, A. S. (1945) Radiolaria
from the Kreyenhagen formation near Los Banos,
California. Geol. Soc. Amer., Mem., 10, 1–66.
Dumitrica, P. (2017) Contribution to the knowledge of
the Entactinaria radiolarian family Rhizosphaeridae
Haeckel and description of some new genera andspecies. Revue de Micropaléontol., 60, 469–491.
Ehrenberg, C. G. (1872) Mikrogeologische Studien überdas kleinste Leben der Meeres-Tiefgrunde aller Zonen
und dessen geologischen Einﬂuss. Abhandlungen derK. Akademie der Wissenschaften zu Berlin, Jahrg,
1872, 131–399.
Foreman, H. P. (1973) Radiolaria of Leg 10 with systematics
and ranges for the families Amphipyndacidae,

Artostrobiidae, and Theoperidae. In Worzel, J.L.,
Bryant, W., et al., eds., Init. Rep. Deep Sea Drilling
Project, 10, Washington, D. C.: U.S. Government
Printing Office, 407–474.
Funakawa, S. (2000) Internal skeletal structures of the
Cenozoic genera Gondwanaria, Lipmanella andLithomelissa (Plagiacanthidae, Nassellaria) and theirtaxonomy. Micropaleontology, 46, 97–121.
Haeckel, E. (1861a) Über neue, lebende Radiolariandes Mittelmeeres und legte die dazu gehörigen
Abbildungen. Monatsberichte der Königlich Preu
βischen Akademie der Wissenschaften zu Berlin,
1860, 794–817.
Haeckel, E. (1861b) Abbildungen and Diagnosen neuer
Gattungen und Arten von lebenden Radiolarien desMittelmeeres, 1860. Monatsberichte der KöniglichPreu βischen Akademie der Wissenschaften zu Berlin,
1860, 835–845.
Haeckel, E. (1879) Natürliche Schöpfungsgeschichte.
Reimer, Berlin, 1–718.
Haeckel, E. (1882) Entwurf eines Radiolarien-System
auf Grund von Studien der Challenger Radiolarien.
Jenaische Zeitschrift Naturwissenschaft, 15, 418–472.
Haeckel, E. (1887) Report on the Radiolaria collected by
H. M. S. Challenger during the years 1873-76. Report
Voyage Challenger, Zoology, 18, 1–140.
Jackett, S. -J., Baumgartner, P. O. and Bandini, A. N.
(2008) A new low-latitude late Paleocene-early
Eocene radiolarian biozonation based on unitaryassociations: applications for accreted terranes.
Stratigraphy, 54, 39–62.
Jørgensen, E. (1905) The protist plankton and the diatoms
in bottom samples. Bergens Museum Skrift, 7, 49–151.
Kamikuri, S. (2010) New late Neogene radiolarian species
from the middle to high latitudes of the North Pacific.
Revue de Micropaléontol., 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. (2017) Late Neogene radiolarian biostratigraphy of the eastern North Pacific ODP Sites
1020/1021. Paleontol. Res., 21, 230–254.
Kling, S. A. (1973) Radiolaria from the eastern North
Pacific, Deep Sea Drilling Project Leg 18. In Kulm, L.
D., von Huene, R., et al., Init. Rep. Deep Sea Drilling
Project, 18, Washington, D. C.: U.S. Government
Printing Office, 617–671.
LaRiviere, J. P., Ravelo, A. C., Crimmins, A., Dekens,
P. S., Ford, H. L., Lyle, M. and Wara, M. W. (2012)
Late Miocene decoupling of oceanic warmth andatmospheric carbon dioxide forcing. Nature, 486,
97–100.
Lombari, G. and Lazarus, D. B. (1988) Neogene
cycladophorid radiolarians from North Atlantic,
Antarctic, and North Pacific deep-sea sediments.
Micropaleontology, 34, 97–135.

− 168 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Lyle, M., Koizumi, I., Richter, C., Behl, R. J., Bodén, P.,
Caulet, J. -P., Delaney, M. L., deMenocal, P., Desmet,
M., Fornaciari, E., Hayashida, A., Heider, F., Hood, J.,
Hova,, S. A., Janecek, T. R., Janik, A. G., Kennett, J.,
Lund, D., Castillo, M. L. M., Maruyama, T., Merrill,
R. B., Mossman, D. J., Pike, J., Ravelo, A. C., Vera, G.
A. R., Stax, R., Tada, R., Thurow, J. and Yamamoto,M. (1997) Proc. Ocean Drilling Program, Init. Rep.,
167, Ocean Drilling Program, College Station, TX,
1–1378.
Matsuzaki, K. M., Suzuki, N. and Nishi, H. (2015) Middle
to Upper Pleistocene polycystine radiolarians fromHole 902-C9001C, northwestern Pacific. Paleontol.
Res., 19, 1–77.
Moore, T. C. Jr. (1972) Mid-Tertiary evolution of theradiolarian genus Calocycletta. Micropaleontology,
18, 144–152.
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, College Station,
TX (Ocean Drilling Program), 55–91.
Motoyama, I. (1996) Late Neogene radiolarian biostratigraphy in the subarctic Northwest Pacific. Micropaleontology, 42, 221–262.
Nigrini C. and Lombari, G. (1984) A guide to Miocene
Radiolaria. Cushman Found. Foram. Res., Spec. Pub.,
22, S1-S102, N1-N206.
Nigrini, C. and Moore, T. C., Jr. (1979) A guide to modern
Radiolaria. Cushman Found. Foram. Res., Spec. Pub.,
16, S1-S142, N1-N106.
O’
Connor, B. (1997) New radiolarian from the Oligocene
and early Miocene of Northland, New Zealand.
Micropaleontology, 43, 63–100.
Perez-Guzman, A. M. (1985) Radiolarian biostratigraphyof the late Miocene in Baja California and the Tres
Marias Islands, Mexico. Micropaleontology, 31,
320–334.
Perez-Guzman, A. M. and Casey, R. E. (1986) Paleoceanographic reconstructions from radiolarian-bearing Baja
California and adjacent sections. In Casey, R. E. andBarron, J. A., eds., Siliceous Microfossil and Microplankton of the Monterey Formation and Modern
Analogs, Society of Economic Paleontologists andMineralogists, Pacific Section, 45, 55–68.
Petrushevskaya, M. G. (1975) Cenozoic radiolarians of
the Antarctic, Leg 29, DSDP. In Kennett, J. P., Houtz,
R. E., et al., Init. Rep. Deep Sea Drilling Project, 29,
Washington (U.S. Govt. Printing Office), 541–675.
Petrushevskaya, M. G. and Kozlova, G. E. (1972)
Radiolaria, Leg 14, Deep Sea Drilling Project. In
Hayes, D. E., Pimm, A. C., et al., Init. Rep. Deep Sea
Drilling Project, 14, Washington (U.S. Govt. Printing
Office), 495–648.
Poore, R. Z., McDougall J. A., Barron, J. A., Brabb, E. E.
and Kling, S. A. (1981) Microfossil biostratigraphy

and biochronology of the type Relizian and Luisianstages of California. In Garrison, R. E. and Douglas,
R. G., eds., The Monterey Formation and Related
Siliceous Rocks of California, Society of Economic
Paleontologists and Mineralogists, Pacific Section,
15, 15–41.
Popova, I. (1989) New insight on the systematics ofsome Theopiliinae (Radiolaria). In Anonymous ed.,
Paleontologo-Stratigraphicheskie Issledavaniya
Fanerozoya, Dal’nego Vostoka, Dal’nevostochniy
Otdel Akademii Nauka SSSR, Vladivostok,
68–77, 131, and 143–145. (in Russian; original title
translated).
Rowell, H. C. (1981) Diatom biostratigraphy of theMonterey Formation, Palos Verdes Hills, California.
In Garrison, R. E. and Douglas, R. G., eds., The
Monterey Formation and Related Siliceous Rocks of
California, Society of Economic Paleontologists andMineralogists, Pacific Section, 15, 55–70.
Sakai, T. (1980) Radiolarians from Sites 434, 435, and436, Northwest Pacific, Leg 56, Deep Sea Drilling
Project. In Scientific Party, Init. Rep. Deep Sea
Drilling Project, 56/57, Washington (U.S. Govt.
Printing Office), 695–733.
Sanfilippo, A. and Caulet, J.-P. (1998) Taxonomy andevolution of Paleogene Antarctic and tropical
Lophocyrtid radiolarians. Micropaleontology, 44,
1–43.
Sanfilippo, A., Westberg-Smith, M. J. and Riedel, W.
R. (1985) Cenozoic radiolaria. In Bolli, H. M.,
Saunders, J. B. and Perch-Nielsen, K., eds., Plankton
Stratigraphy, Cambridge Univ. Press, Cambridge,
UK, 631–712.
Shilov, V. V. (1995) Miocene-Pleistocene radiolarians
from Leg 145, North Pacific. In Rea, D. K., Basov, I.
A., Scholl, D. W. and Allan, J. F., eds., Proc. Ocean
Drilling Program, Sci. Results, 145, College Station,
TX (Ocean Drilling Program), 93–116.
Sugiyama, K. and Furutani, H. (1992). Middle Miocene
radiolarians from the Oidawara Formation, Mizunami
Group, Gifu Prefecture, central Japan. Bull. Mizunami
Fossil Mus., 19, 199-213.
Suzuki, N., Ogane, K. and Chiba, K. (2009) Middle Eocene
polycystine radiolarians from the Site 1172, Leg 189,
Southwest Pacific. News Osaka Micropaleontol.
(NOM), Spec. Vol., no. 14, 239–296.
Takahashi, K. (1991) Radiolaria: ﬂux, ecology, andtaxonomy in the Pacific and Atlantic. Ocean
Biocoenosis Series, no. 3, Woods Hole Oceanographic
Institution, 1–303.
Takahashi, K. and Honjo, S. (1981) Vertical fluxof Radiolaria: A taxon-quantitative sediment
trap study from the western tropical Atlantic.
Miocropaleontology, 27, 140–190.
Takemura, A. (1992) Radiolarian Paleogene biostratigraphy
in the Southern Indian Ocean, Leg 120. In Wise, S.
W., Jr., Schlich, R., et al., Proc. ODP, Sci. Results,− 169 −

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

120, College Station, TX (Ocean Drilling Program),
735–756.
Vitukhin, D. I. (1993) Subdivision of the Russian Far
East Cenozoic sediments based on Radiolaria.
Transactions, Geol. Inst., Russian Academi Sci., 485,
p. 1–105. (in Russian with English abstract).
Weaver, F. M., Casey, R. E. and Perez, A. M. (1981)
Stratigraphic and paleoceanographic signiﬁcanceof early Pliocene to middle Miocene radiolarianassemblages from Northern to Baja California.
In Garrison, R. E. and Douglas, R. G., eds., The
Monterey Formation and Related Siliceous Rocks of

California, Society of Economic Paleontologists andMineralogists, Paciﬁc Section, 15, 71–86.
Zhang, L. and Suzuki, N. (2017) Taxonomy and species
diversity of Holocene pylonioid radiolarians fromsurface sediments of the northeastern Indian Ocean.
Palaeontol. Electron., 20.3.48A, 1–68.

Recieved December 19, 2017
Accepted September 18, 2018
Published on-line January 18, 2019北東太平洋における国際深海掘削計画（ODP）1021 地点の中部および上部中新統から産出した放散虫化石
上栗伸一
要 旨
北東太平洋における国際深海掘削計画（ODP）1021地点の中部および上部中新統から，合計149種の放散虫化石が産出した．その写真を24枚のプレートに示した．これらの分類群にはActinom moidea科，Eurcy r tidioidea科，Hexast ylioidea
科，Litheliid ae科，Lych nocanoidea科およびSpongodiscid ae科を含む40の未同定種が含まれている．本論文において
Lychnocanoma californicaを新種として記載した．

− 170 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 1

2a
1a

3a

4a

6b

9a

100 µm

1b

3b

6a

2b

9b

4b

7a

7b

10a

10b

5a

5b

8a

8b

11a

11b

15a
12a
Plate 1

12b

13a

13b

14a

15b

14b

Illustrations of the encountered radiolarians. 1: Cycladophora cabrilloensis (Campbell and Clark) (Sample 1021B-26X-4,
70-72 cm, 9.0 Ma); 2: Cycladophora cosma Lombari and Lazarus (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 3:
Cycladophora klingi Lombari and Lazarus (Sample 1021B-26X-6, 20-22 cm, 9.0 Ma); 4: Cycladophora bicornis (Popofsky)(Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 5: Cycladophora sphaeris (Popova) (Sample 1021B-22X-6, 20-22 cm, 7.8 Ma);
6–11: Lychnocanoma californica n. sp. (6–8, 11: Sample 1021B-26X-4, 70-72 cm, 9.0 Ma; 9, 10: Sample 1021B-26X-2,
120-122 cm, 8.9 Ma); 12: Botryostrobus bramlettei (Campbell and Clark) (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 13:
Phormostichoartus fistula Nigrini (Sample 1021B-32X-6, 20-22 cm, 12.2 Ma); 14: Spirocyrtis subscalaris Nigrini (Sample
1021B-26X-6, 20-22 cm, 9.0 Ma); 15: Carpocanium favosa (Haeckel) (Sample 1021B-32X-6, 20-22 cm, 12.2 Ma).
− 171 −

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

Plate 2

2a

1b

2b

1a

3a

3b
100 µm4

5aPlate 25b

6

7Illustrations of the encountered radiolarians. 1, 2: Lychnocanoma nipponica (Nakaseko) (Sample 1021B-33X-2, 120-122 cm,
12.5 Ma); 3: Lychnodictyum aff. audax Riedel (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 4: Lamprotripus cortina (Haeckel)(Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 5: Lychnocanoma magnacornuta Sakai (Sample 1021B-29X-4, 70-72 cm, 10.2Ma); 6: Lamprotripus splendens (Campbell and Clark) (Sample 1021B-29X-2, 120-122 cm, 10.1 Ma); 7: Pterocanium sp. A(Sample 1021B-32X-4, 70-72 cm, 12.1 Ma).
− 172 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 3

1a

1b
2a

2b
3a

4a

4b

5a

5b
3b
100 µm6a9aPlate 3

6b

9b

7a

10a

10b

8a

7b

11

12

8b

13

Illustrations of the encountered radiolarians. 1: Calocycletta caepa Moore (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 2, 3:
Calocycletta sp. C (2: Sample 1021B-32X-6, 20-22 cm, 12.8 Ma; 3: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 4: Calocycletta
sp. B (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 5: Calocycletta sp. A (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 6:
Lophoconus bihastatus Clark and Campbell (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 7: Theocorythium sp. A (Sample
1021B-26X-4, 70-72 cm, 9.0 Ma); 8: Albatrossidium sp. C (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 9, 10: Anthocyrtidium
sp. A (9: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma; 10: Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 11: Anthocyrtidium sp. B(Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 12, 13: Lamprocyclas sp. C (Sample 1021B-29X-4, 70-72 cm, 10.2 Ma).
− 173 −

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

Plate 4

2a
1a

11

1b

4a

4b

7a

7b

12a

2b

100 µm

5a

6a

5b

8a

12b

3

8b

13a

6b

10

9

13b
14a

14b

Plate 4 Illustrations of the encountered radiolarians. 1–3: Lamprocyclas hannai (Campbell and Clark) type A (1, 3: Sample 1021B-33X-2,
120-122 cm, 12.5 Ma; 2: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma); 4–6: Lamprocyclas hannai (Campbell and Clark) type B(4, 5: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma; 6: 1021B-32X-4, 70-72 cm, 12.1 Ma); 7: Eucyrtidium hexagonatum Haeckel(Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 8: Eucyrtidium calvertense Martin (Sample 1021B-31X-6, 20-22 cm, 11.6 Ma);
9–11: Eucyrtidium cienkowskii Haeckel group (9, 10: Sample 1021B-26X-4, 70-72 cm, 9.0 Ma; 11: Sample 1021B-28X-6,
20-22 cm, 9.8 Ma); 12: Eucyrtidium sp. E (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 13: Eucyrtidium inflatum Kling(Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 14: Eucyrtidium sp. G (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 174 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 5

1a

1b

2a

5a

3

2b

5b
7

4a

100 µm

4b

9a
8a

6

9b

10

8b

13

14a

14b

11

15a

15b

12

16a
Plate 5

16b

17a

17b

Illustrations of the encountered radiolarians. 1, 2: Lithopera renzae Sanfilippo and Riedel (1: Sample 1021B-32X-6, 20-22 cm,
12.2 Ma; 2: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 3: Lithopera neotera Sanfilippo and Riedel (Sample 1021B-32X-6,
20-22 cm, 12.2 Ma); 4: Cyrtocapsella cornuta Haeckel (Sample 1021B-33X-4, 70-72 cm, 12.7 Ma); 5: Cyrtocapsella tetrapera
Haeckel (Sample 1021B-33X-4, 70-72 cm, 12.7 Ma); 6: Stichocorys peregrina (Riedel) (Sample 1021B-28X-6, 20-22 cm, 9.8Ma); 7: Stichocorys delmontensis (Campbell and Clark) (Sample 1021B-31X-6, 20-22 cm, 11.6 Ma); 8, 9: Cyrtocapsella japonica(Nakaseko) (8: Sample 1021B-33X-4, 70-72 cm, 12.7 Ma; 9: Sample 1021B-32X-4, 70-72 cm, 12.1 Ma); 10, 11: Ceratocyrtis
aff. mashae Bjørklund (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 12: Ceratocyrtis sp. A (Sample 1021B-33X-2, 120-122
cm, 12.5 Ma); 13: Ceratocyrtis sp. C (Sample 1021B-32X-6, 20-22 cm, 12.2 Ma); 14: Eucyrtidium sp. D (Sample 1021B-32X-4,
70-72 cm, 12.1 Ma); 15: Eucyrtidium inflatum Kling (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 16: Dictyophimus sp. A(Sample 1021B-32X-4, 70-72 cm, 12.1 Ma); 17: Pterocanium sp. A (Sample 1021B-32X-4, 70-72 cm, 12.1 Ma).
− 175 −

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

Plate 6

1a

3a

1b
2a

4a

5a

4b

3b

2b

6a

5b

6b

7

9a
8a

8b

100 µm11a
10a

Plate 6

12

11b

10b

14
13

9b

15

16

17

Illustrations of the encountered radiolarians. 1: Lophocyrtis aspera (Ehrenberg) (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 2:
Gondwanaria campanulaeformis (Campbell and Clark) (Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 3: Cornutella paloverdensis
Campbell and Clark (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 4: Lithomelissa cf. ultima Caulet (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 5: Lithomelissa sp. A (Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 6: Lithomelissa sp. B (Sample
1021B-28X-6, 20-22 cm, 9.8 Ma); 7: Cinclopyramis murrayana Haeckel (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 8–10:
Lipmanella redondoensis (Campbell and Clark) (8: Sample 1021B-26X-2, 120-122 cm, 8.9 Ma; 9: Sample 1021B-26X-4, 70-72
cm, 9.0 Ma; 10: 1021B-33X-4, 70-72 cm, 12.7 Ma); 11: Lipmanella hister (Petrushevskaya) (Sample 1021B-26X-4, 70-72
cm, 9.0 Ma); 12: Theocorys perforalvus O’Connor (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 13, 14, 17: Cinclopyramis
circumtexta (Haeckel) group (13, Sample 1021B-28X-6, 20-22 cm, 9.8 Ma; 14: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma;
17: Sample 1021B-24X-1, 120-122 cm, 8.1 Ma); 15: Cornutella profunda Ehrenberg (Sample 1021B-26X-4, 70-72 cm, 9.0Ma); 16: Cyrtolagena sp. A (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 176 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 7

1a

2b

2a

1b

100 µm

3a

5a

4a

3b

7a

7b

5b

8a

8b

6a

6b

9a

9b

14a

12

10

14b

13

11
Plate 74b

Illustrations of the encountered radiolarians. 1, 2: Lophospyris laventaensis (Campbell and Clark) (Sample 1021B-26X-4, 70-72
cm, 9.0 Ma); 3–5: Dendrospyris sp. A (3, 4: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma; 5: Sample 1021B-32X-6, 20-22
cm, 12.2 Ma); 6: Dendrospyris sp. B (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 7: Phormospyris stabilis (Goll) (Sample
1021B-33X-2, 120-122 cm, 12.5 Ma); 8: Dendrospyris sp. C (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 9: Dendrospyris
sp. D (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 10: Tholospyris kantiana (Haeckel) (Sample 1021B-33X-2, 120-122 cm,
12.5 Ma); 11: Dendrospyris sp. E (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 12, 13: Dendrospyris aff. bursa (Sanfilippo andRiedel) (Sample 1021B-29X-2, 120-122 cm, 10.1 Ma); 14: Dendrospyris sp. F (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 177 −

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

Plate 8

1a

2

1b

4a
3a

3b
100 µm4b5a7aPlate 8

5b

7b

6a

6b

8a

8b

Illustrations of the encountered radiolarians. 1–8: Rhizosphaera churchi (Campbell and Clark) group (1–4, 7: Sample
1021B-26X-4, 70-72 cm, 9.0 Ma; 5: Sample 1021B-27X-1, 20-22 cm, 9.1 Ma; 6: Sample 1021B-33X-2, 120-122 cm, 12.5
Ma; 8: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma).
− 178 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 9

2a
1a

3a

5a

7a
Plate 92b1b

100 µm

4a

4b

6a

6b

3b

5b

7b

8a

8b

9a

9b

Illustrations of the encountered radiolarians. 1–9: Haliommetta miocenica (Campbell and Clark) group (1, 2, 4: Sample
1021B-33X-2, 120-122 cm, 12.5 Ma; 3, 6–8: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma; 5: 1021B-28X-6, 20-22 cm, 9.8 Ma).
− 179 −

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

Plate 10

1a

1b

2a

100 µm

2b
3a

3b

5a

4a

4b
5b

6a

7a

6b

7b

Plate 10 Illustrations of the encountered radiolarians. 1–4: Actinomma hootsi (Campbell and Clark) (Sample 1021B-33X-2, 120-122
cm, 12.5 Ma); 5–7: Excentrodiscus japonicus (Nakaseko and Nishimura) (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma).
− 180 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 11

1a

1b

2a

2b
3a

3b

4a

4b

6a

6b

8a

8b

100 µm

7a

7b

9a

9b

5a

5b

Plate 11 Illustrations of the encountered radiolarians. 1: Hexacontium sp. A (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 2, 3: Hexacontium sp. B(2: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma; 3: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma); 4, 5: Hexacontium aff. arachnoidale
Hollande and Enjumet (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 6–9: Hexacontium minerva Kamikuri (6, 8: Sample 1021B-32X-6,
20-22 cm, 12.2 Ma; 7: Sample 1021B-28X-6, 20-22 cm, 9.8 Ma; 9: Sample 1021B-29X-4, 70-72 cm, 10.2 Ma).
− 181 −

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

Plate 12

1a

2a

2b

3a

3b

100 µm

1b

4a

6a

5a

4b

6b

7a

7b

5b

8a

8b

Plate 12 Illustrations of the encountered radiolarians. 1: Hexacontium sp. E (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 2: Hexastylus
sp. A (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 3: Hexastylus aculeata (Campbell and Clark) (Sample 1021B-32X-6, 20-22
cm, 12.2 Ma); 4–8: Actinomma robusta (Kling) (4, 7: Sample 1021B-26X-4, 70-72 cm, 9.0 Ma; 5, 6: Sample 1021B-28X-6,
20-22 cm, 9.8 Ma; 8: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma).
− 182 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 13

1a

1b

2a

2b

3a

4a

4b

5a

5b

3b

6a

6b

7a

7b

9a

12a

9b

12b

10a

13a

8

10b

13b

11

100 µm

14a

14b

15a

15b
16

Plate 13 Illustrations of the encountered radiolarians. 1–8: Thecosphaera dedoensis Nakaseko (1–5: Sample 1021B-32X-6, 20-22 cm,
12.2 Ma; 6: 1021B-26X-4, 70-72 cm, 9.0 Ma; 7, 8: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 9, 10: Thecosphaera sp. A(Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 11: Saturnalis circularis Haeckel (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 12–15:
Thecosphaera sp. B (12, 13, 15: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma; 14: Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 16:
Liosphaera hexagonia Haeckel (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma).
− 183 −

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

Plate 14

1a

1b

4a

4b

8a
7a

2a

2b

5a

5b

8b

7b

9a

12

11a

3a

3b

6a

6b

10a

10b

9b

13a

13b
100 µm11b

Plate 14 Illustrations of the encountered radiolarians. 1–3: Stylosphaera radiosa Ehrenberg (1: Sample 1021B-32X-6, 20-22 cm, 12.2
Ma; 2, 3: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 4–6: Cromydruppocarpus esterae Campbell and Clark (Sample
1021B-33X-2, 120-122 cm, 12.5 Ma); 7: Druppatractus hastatus Blueford (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma);
8–10: Stylosphaera timmsi (Campbell and Clark) (8, 10: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma; 9: Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 11: Axoprunum bispiculum (Popofsky) (Sample 1021B-28X-6, 20-22 cm, 9.8 Ma); 12: Stylatractus
universus Hays (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 13: Amphistylus angelinus (Campbell and Clark) (Sample
1021B-32X-6, 20-22 cm, 12.2 Ma).
− 184 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 15

1a

4a

4b

6a

6b

100 µm

3b

5a

5b

8a

7b

10a
9a

2b

1b

3a

7a

2a

9b

8b

10b

11a

11b

Plate 15 Illustrations of the encountered radiolarians. 1–11: Cenosphaera jenkinsi Campbell and Clark group (1, 3, 5: Sample
1021B-28X-6, 20-22 cm, 9.8 Ma; 2, 4, 6–11: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma).
− 185 −

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

Plate 16

1a

2a

1b

2b

5a
3a

3b

6a

4a

4b

7a

6b

7b

5b

9a

9b

100 µm8a8bPlate 16 Illustrations of the encountered radiolarians. 1, 2: Styptosphaera spumacea Haeckel (Sample 1021B-32X-6, 20-22 cm, 12.2
Ma); 3–5: Stylatractus neptunus Haeckel (3: Sample 1021B-32X-6, 20-22 cm, 12.2 Ma; 4: Sample 1021B-26X-6, 20-22 cm,
9.0 Ma; 5: Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 6, 7: Cenosphaera jenkinsi Campbell and Clark group (Sample
1021B-32X-6, 20-22 cm, 12.2 Ma); 8: Actinomma hootsi (Campbell and Clark) (Sample 1021B-33X-2, 120-122 cm, 12.5
Ma); 9: Stylatractus santaeannae (Campbell and Clark) (Sample 1021B-32X-6, 20-22 cm, 12.2 Ma).
− 186 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 17

1a

1b

2a

2b

3a

3b

4a

4b

5a

7

5b

8a

10a

6a

6b

100 µm

8b

10b

9a

9b

11a

11b

Plate 17 Illustrations of the encountered radiolarians. 1–6: Collosphaera glebulenta Bjørklund and Goll (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 7: Collosphaera reynoldsi Kamikuri (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 8: Collosphaera
sp. B (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 9: Collosphaera sp. A (Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 10:
Polysolenia pseudarktios (Caulet) (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 11: Polysolenia murrayana (Haeckel)(Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 187 −

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

Plate 18

2

1

3

5

4

100 µm

7

13

18

8

9

10

15

14

20

19

11

6

12

16

17

21

22

Plate 18 Illustrations of the encountered radiolarians. 1: Lithelius klingi Kamikuri (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 2:
Lithelius minor Jørgensen group (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 3: Larcospira quadrangula Haeckel group(Sample 1021B-33X-2, 120-122 cm, 12.5 Ma), 4: Lithelius aff. elliptica (Ehrenberg) (Sample 1021B-33X-2, 120-122 cm,
12.5 Ma); 5: Larcopyle aff. pylomaticus (Riedel) (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 6: Larcopyle sp. A (Sample
1021B-33X-2, 120-122 cm, 12.5 Ma); 7–11: Larcopyle polyacantha (Campbell and Clark) type A (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 12: Larcopyle polyacantha (Campbell and Clark) type B (Sample 1021B-33X-2, 120-122 cm, 12.5
Ma); 13–17: Larcopyle polyacantha (Campbell and Clark) type C (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 18–22:
Larcopyle buetschlii Dreyer (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 188 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 191
100 µm
2
3

6
8

4

5

15
16

15

20

21

22

12

11

13

9

7

14

10

19

16
385
17

23

18

24

25

Plate 19 Illustrations of the encountered radiolarians. 1, 2: Dictyocoryne malagaense (Campbell and Clark) group (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 3: Dictyocoryne sp. A (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 4: Amphymenium amphistylium
Haeckel (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 5: Spongurus cylindricus Haeckel (Sample 1021B-33X-2, 120-122 cm,
12.5 Ma); 6, 7: Tetrapyle circularis/fruticosa group (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma); 8–10: Phorticium sp. A (Sample
1021B-26X-2, 120-122 cm, 8.9 Ma); 11–13: Phorticium clevei (Jørgensen) (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma); 14:
15: Didymocyrtis penultima (Riedel) (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma); 16, 17: Didymocyrtis laticonus (Riedel)(Sample 1021B-33X-4, 70-72 cm, 12.7 Ma); 18, 19: Didymocyrtis antepenultima (Riedel and Sanfilippo) (Sample 1021B-32X-1,
20-22 cm, 11.7 Ma); 20, 21: Diartus hughesi (Campbell and Clark) (20: Sample 1021B-26X-2, 120-122 cm, 8.9 Ma; 21: Sample
1021B-28X-6, 20-22 cm, 9.8 Ma); 22, 23: Didymocyrtis sp. C (Sample 1021B-31X-6, 20-22 cm, 11.6 Ma); 24, 25: Didymocyrtis
sp. D (24: Sample 1021B-26X-2, 120-122 cm, 8.9 Ma; 25: Sample 1021B-27X-1, 20-22 cm, 9.1 Ma).
− 189 −

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

Plate 20

2

1

3

4

9

8
6

5

10

7

12

11

13

17
15

14

16

100 µmPlate 20 Illustrations of the encountered radiolarians. 1–4: Circodiscus circularis (Clark and Campbell) (Sample 1021B-33X-2, 120-122
cm, 12.5 Ma); 5–9: Stylodictya sp. A (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 10–15: Perichlamydium scutaeforme
Campbell and Clark type A (10, 14, 15: Sample 1021B-26X-2, 120-122 cm, 8.9 Ma; 11–13: Sample 1021B-26X-4, 70-72
cm, 9.0 Ma); 16: Perichlamydium sp. P (Sample 1021B-25X-4, 70-72 cm, 8.6 Ma); 17: Larcospira moschkovskii Kruglikova(Sample 1021B-33X-2, 120-122 cm, 12.5 Ma).
− 190 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 214
1

100 µm

2

3

5

9

8

7

6

11

10

12

13

14

Plate 21 Illustrations of the encountered radiolarians. 1–12: Spongodiscus resurgens Ehrenberg (Sample 1021B-33X-2, 120-122 cm,
12.5 Ma); 13: Spongaster sp. A (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 14: Spongodiscus sp. D (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma).
− 191 −

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

Plate 222
1

100 µm

8

3

4
9

5

6

7

10

Plate 22 Illustrations of the encountered radiolarians. 1: Spongotrochus sp. B (Sample 1021B-24X-4, 70-72 cm, 8.3 Ma); 2–4:
Spongotrochus sp. C (Sample 1021B-24X-4, 70-72 cm, 8.3 Ma); 5–7: Spongopyle osculosa Dreyer (Sample 1021B-33X-2,
120-122 cm, 12.5 Ma); 8: Larcospira moschkovskii Kruglikova (Sample 1021B-33X-2, 120-122 cm, 12.5 Ma); 9, 10: Larcospiraquadrangula Haeckel group (9: Sample 1021B-26X-2, 120-122 cm, 8.9 Ma; 10: Sample 1021B-27X-1, 20-22 cm, 9.1 Ma).

− 192 −

Middle to late Miocene radiolarians in the eastern North Pacific (Kamikuri)

Plate 233
2
1

100 µm

5

4

6

8

7

9

10

11

12

Plate 23 Illustrations of the encountered radiolarians. 1–6: Stylodictya ornata Campbell and Clark (Sample 1021B-26X-2, 120-122 cm,
8.9 Ma); 7, 8: Stylodictya tenuispina Jørgensen (Sample 1021B-25X-4, 70-72 cm, 8.6 Ma); 9, 10: Perichlamydium scutaeforme
Campbell and Clark type B (Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 11, 12: Perichlamydium scutaeforme Campbell and
Clark type C (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma).
− 193 −

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

Plate 24

3

2

1

4
3

6

7

8

9

5
100 µmPlate 24 Illustrations of the encountered radiolarians. 1: Spongotrochus sol Campbell and Clark type A (Sample 1021B-26X-2, 120-122
cm, 8.9 Ma); 2: Spongotrochus sol Campbell and Clark type B (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma); 3, 4: Spongotrochus
sp. Z (Sample 1021B-26X-2, 120-122 cm, 8.9 Ma); 5, 6: Spongodiscus cauleti Kamikuri (5: Sample 1021B-31X-1, 20-22 cm,
11.1 Ma; 6: Sample 1021B-30X-4, 70-72 cm, 10.8 Ma); 7, 8: Perichlamydium sp. K (7: Sample 1021B-26X-2, 120-122 cm,
8.9 Ma; 8: Sample 1021B-26X-4, 70-72 cm, 9.0 Ma); 9: Heliodiscus sp. A (Sample 1021B-26X-6, 20-22 cm, 9.0 Ma).
− 194 −