御所浦白亜紀資料館報，第20号，7–21ページ，2019年3月．
Bull. Goshoura Cret. Mus., No.20, 7-21, March, 2019.

Checklist of ostracods from the Pleistocene Ogushi
Formation, Amakusa City, Kumamoto, southwestern Japan
GengoTANAKA,1 Takumi MAEKAWA,2 Ryota URAKAWA,3 Toshifumi KOMATSU 4 and Yasuhisa HENMI 2( 1 Institute of Liberal Arts and Science, Kanazawa University Kakuma-machi, Kanazawa City, Ishikawa 920-1192, Japan )( 2 Aitsu Marine Station, Center for Water Cycle, Marine Environment and Disaster Management, Kumamoto University,
6061, Aitsu, Matsushima, Kami-amakusa City, Kumamoto 861-6102, Japan )( 3 Suncoh Consultant Co., Ltd., 1-8-9 Kamedo, Koutou-ku, Tokyo 136-0071, Japan )( 4 Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan)

Abstract
Abstract
Here
Ogushi Formation,
Formation,Itsuwa
ItsuwaTown,
Town,Amakusa
AmakusaCity,
City,
Hereweweshow
showthethechecklist
checklistofof Ostracoda
Ostracoda fromfrom thethe Pleistocene
Pleistocene Ogushi
Kumamoto
from thesediments. Twenty-four
Twenty-four genera
generaKumamoto Prefecture,
Prefecture, Japan
Japan forfor identifying
identifying ostracods
ostracods fromthe Quaternary
Quaternary sediments.
including39
ostracods
speciesaresystematicallycheckedandillustrated.
Shallowmarinetropicalostracodincluding 39 ostracods species are systematically checked and illustrated. Shallow marine tropical ostracod
Kotoracythere
the Ogushi
Ogushi Formation
Formationin
inthisthisstudy.
study.
Kotoracythereinconspicua
inconspicua(Brady,(Brady,1880)
1880) was
was firstly
firstly reported
reported fromfrom theKeywords
Keywords: :Crustacea,
Crustacea,Ogushi
OgushiFormation,
Formation,Ostracoda,
Ostracoda,Podocopida,
Podocopida,Systematics
Systematics
Introduction
Introduction
Ostracods
Ostracodsare
aretinytinycrustaceans
crustaceansthat
thathavehavelong
longstratigraphicalstratigraphicalwhich
Thisarticle
articlewhich occurredoccurred fromfromthetheOgushi
OgushiFormation.
Formation.This

fossilfossilrecord
recordatatleast
least500
500million
millionyears
years(e.g.,(e.g.,Williams
Williamset etal.,al.,focusesfocuseson
onthe
thesystematics
systematicsand
andillustration
illustrationfor
foridentifying
identifyingthe
the

2008)
2008) andand provide
provide good
good indicator
indicator forfor reconstructing
reconstructing

ostracods
ostracodsfrom
fromthetheOgushi
OgushiFormation.
Formation.

paleoenvironment.
paleoenvironment. Also,
Also, because
because ostracods
ostracods (especially(especially
Podocopa),
Podocopa),that
thatweweexamine
examinehere,
here,some
someofofwhich
whichhave
havebeen
been
shown
showntotobebeimportant
importantindicesindicesforforreconstructing
reconstructingCenozoic
Cenozoic

Materials
methods
Materials and methods
Unconsolidated
Unconsolidatedlight-graylight-graymud
mudwithwithshellshellfragments
fragmentswas
waspaleogeography
paleogeography (e.g.,(e.g., Tanaka
Tanaka etet al.,al., 2018).
2018). The
The
paleoenvironmental
thetheOgushipaleoenvironmentalanalysis
analysisusing
usingostracods
ostracodsfrom
fromOgushiused
usedininthis
thisstudy.
study.The
Theoriginal
originalmud
mudwaswasputted
puttedinto
intoa abucket
bucketandandadded
addedhothotwaterwater(around(around9898degrees).
degrees).The
Thesamples
sampleswere
were

Formation
Formationwas
wasalreadyalreadydone
donebybyKawano
Kawanoetetal.al.(2011).
(2011).
AccordingtoKawanoetal.
(2011),
theOgushi
Formation
According to Kawano et al. (2011), the Ogushi Formation

washedwashedthroughthroughaasieve
sieveofofthe
theopening
openingofof125
125μm
μmand
anddrieddried
ininanovenat80
degrees
in
the
Aitsu
MarineStation(AMS)
an oven at 80 degrees in the Aitsu Marine Station (AMS)waswasdeposited
depositedduring
duringthe
theLateLatePleistocene
Pleistocene(MIS(MIS7),7),thethe
outcropoutcropofofthis
thisageageisisextremely
extremelyrare
rareininthetheKyushu
KyushuIsland,
Island,atat Kumamoto
Kumamoto University.
University.Ostracod
Ostracodspecimens
specimenspicked
pickedout
out
microscopeby
21
undergraduate
students
understereoscopic
under stereoscopic microscope by 21 undergraduate students

Japan.
Japan.The
Theoccurrence
occurrenceofofNeomonoceratina
Neomonoceratinadelicata
delicatafrom
from
this
formation
byKawanoetal.
(2011)
confirmed
thatthethis formation by Kawano et al. (2011) confirmed that the

species
speciesexisted
existedduring
duringthe
theLateLatePleistocene
Pleistocenefrom
fromKyushu
Kyushutoto
HonshuHonshuislands,
islands,Japan.
Japan.Present
Presentdistribution
distributionN.N.delicata
delicatais is

fromfromJava
JavaSeas
SeastotoRyukyu
RyukyuIslands
Islands(till(tillTokara
TokaraStraight)
Straight)viavia
the
2009;
thecoast
coastofofChina
Chinaandandnorthern
northernVietnam
Vietnam(Irizuki(Irizukietetal.,al.,2009;

TanakaTanakaetetal.,al.,2009).
2009).Although
Althoughthe
theostracod
ostracodassemblages
assemblages
fromtheOgushi
Formation
provideupdatingoffrom the Ogushi Formation provide updating ofostracod
ostracodpaleobiogeography
etetal.al.
paleobiogeographyduring
duringthe
theLateLatePleistocene,
Pleistocene,Kawano
Kawano(2011)
thethespecies(2011)did
didnotnotillustrate
illustrateand
andmention
mentionabout
about
species(see(see Tanaka
TanakaandandParticipantsParticipantsofof2016
2016basebaseexperimentexperimentofof
earth
earthsciencescienceclassclassininKumamoto
KumamotoUniversity,
University,2019),
2019),G.T.,
G.T.,T.T.
M.,
M.,R.
R.U.
U.and
andthen
thendigital
digitalimages
imagesofofselected
selectedspecimens
specimenswere
were
observed
observed andandtook
tookusingusingaaHITACHIHITACHITM-1000
TM-1000scanningscanning
electronelectronmicroscope
microscope(SEM)(SEM)under
undera alow
lowvacuum,
vacuum,and
andwithwitha anon-evaporation
non-evaporationcoating
coatingatatAMS.
AMS.

8

Systematic Palaeontology

Paradoxostoma setoense Schornikov, 1975, p. 27, 28, fig. 14.

The asterisk mark in front of each species name shows that

Remarks –This species was described by Schornikov (1975)

the species described with appendages by the author(s) oron the basis of the carapace and appendages (except forother author(s).

thoracopod III) from the rocky intertidal zone near the Seto
Marine Biological Laboratory, Seto Inland Sea, Japan.

Class Ostracoda Latreille, 1802

Okubo (1977) mentioned sexual dimorphism of color pattern

Family Bairdiidae Sars, 1865of the valve between female and male: The carapace ofGenus Neonesidea Maddocks, 1969

female has dark blue pigments almost of all areas under the
carapace, but the male is only pigmented dorso-central areas

Neonesidea sp.

with dark blue pigment.

Fig. 3.14
Family Cytheruridae G. W. Müller, 1894
Remarks – This fragmented specimen seems to Neonesidea

Genus Hemicytherura Elofson, 1941

oligodentata (Kajiyama, 1913), but it is difficult to identify
because of the juvenile stage. Because we could not discover*Hemicytherura choeae Kaseda et Ikeya, 2011

completely adult specimen, we did not identify the specimen.

(Tanaka et al., 2011 in reference)

Kajiyama (1913) firstly described this species with antennule,Figs. 2.6, 2.7

antenna, mandible, maxilla, fifth and sixth limbs, and furca.
Appendages including male copulatory organ was described

Hemicytherura choeae Kaseda et Ikeya, 2011, p. 32–34, figs.

by Okubo (1975a). Smith and Kamiya (2002) described

3F, 4E, 12.1a–12.1f, 12.2a –12.2f.

ontogenetic change of shell size, appendages and number ofRemarks – Kaseda and Ikeya, 2011 (in Tanaka et al., 2011)

pore canals of this species.

described the carapace and appendages from the rocky shore,
Hakona-Irie, coast of southern Noto-jima Island,

Family Bythocytheridae Sars, 1926

northeastern Noto Peninsula, central Japan.

Genus Bythoceratina Hornibrook, 1952
*Hemicytherura cuneata Hanai, 1957
Bythoceratina subjaponica Zhou, 1995

(Hanai, 1957b in reference)

Fig. 1.15

Fig. 2.8

Bythoceretina subjaponica Zhou, 1995, p. 80, 81, pl. 4, figs.

Hemicytherura cuneata Hanai, 1957, p. 24, 25, pl. 2, figs. 2a,5, 6a, 6b.

2b, text-figs. 1a, 1b.

Remarks – Zhou (1995) described this species from theRemarks – Hanai (1957b) described this species from the

Recent sediment of Hyuga-nada, Kyushu Island. The

Recent sand collected at a shore behind an Imperial villa,

specimens consisted of one right valve (holotype) and one

Hayama-cho, Kanagawa Prefecture, Japan (see Ikeya et al.,left valve (paratype), and recovered from 42 m in depth.

2003). The materials consist of two complete carapaces

Zhou mentioned that this species also occurred from Recent(holotype and paratype). All appendages including malesamples from the Tosa Bay, Kumano-nada and off Tanabe.

copulatory organ of this species were described by Okubo

There are no soft parts description.

(1980).

Family Paradoxostomatidae Brady and Norman, 1889

*Hemicytherura tricarinata Hanai, 1957（Hanai, 1957b inGenus Hemicytherura Fischer, 1855

reference）
Figs. 2.9, 2.10, 4.16

*Paradoxostoma setoense Schornikov, 1975
Fig. 3.15

Hemicytherura tricarinata Hanai, 1957, p. 25, 26, pl. 2, figs.
3a, 3b.

9

Fig.1. SEM images of ostracods from the Pleistocene Ogushi Formation, Amakusa, Kyushu, Japan. 1–4. Aurila cymba (Brady,
1869). 1. Right lateral view of adult specimen. 2. Left lateral view of adult specimen. 3. Left lateral view of juvenile specimen. 4.
Left lateral view of juvenile specimen. 6–8. Aurila hataii Ishizaki, 1968. 5. Left lateral view of juvenile specimen.6. Left lateral viewof juvenile specimen. 7. Right lateral view of juvenile specimen. 8. Left lateral view of juvenile specimen. 9–14. Bicornucythere
bisanensis s.l. (Okubo, 1975), 9. Right lateral view of adult male specimen. 10. Left lateral view of adult male specimen. 11. Leftlateral view of adult female specimen. 12. Right lateral view of adult female specimen. 13. Left lateral view of juvenile specimen.
14. Left lateral view of juvenile specimen.15. Fragmented left lateral view of juvenile specimen. of Bythoceratina subjaponica
Zhou, 1995 16. Callistocythere hotaru Yajima, 1982, left lateral view of adult specimen. 17–20. Callistocythere hayamensis Hanai,
1957. 17. Left lateral view of adult male specimen. 18. Left lateral view of adult female specimen. 19. Right lateral view of adultfemale specimen. 20. Left lateral view of juvenile specimen.

10

Fig. 2. SEM images of ostracods from the Pleistocene Ogushi Formation, Amakusa, Kyushu, Japan. 1. Cytheromorphaacupunctata (Brady, 1880), left lateral view of adult male specimen. 2. Cobanocythere sp., right lateral view of adult specimen. 3,
4. Coquimba ishizakii Yajima, 1978. 3. Right lateral view of adult specimen. 4. Left lateral view of juvenile specimen. 5. Cythere
nishinipponica Okubo, 1976, right lateral view of juvenile specimen. 6, 7. Hemicytherura choeae Kaseda et Ikeya, 2011 in
Tanaka et al. (2011). 6. Left lateral view of adult specimen. 7. Left lateral view of adult specimen. 8. Hemicytherura cuneata Hanai,
1957, left lateral view of adult female specimen. 9, 10. Hemicytherura tricarinata Hanai, 1957. 9. Right lateral view of adultspecimen. 10. Left lateral view of juvenile specimen. 11. Kotoracythere inconspicua (Brady, 1880), left lateral view of adultspecimen. 12–15. Loxoconcha tosaensis Ishizaki, 1968 12. Left lateral view of adult female specimen. 13. Right lateral view ofadult female specimen. 14. Right lateral view of adult male specimen. 15. lateral view of juvenile specimen. 16–18. Loxoconcha
harimensis Okubo, 1980. 16. Right lateral view of adult female specimen. 17. Right lateral view of adult male specimen. 18. Rightlateral view of juvenile specimen. 19, 20. Loxoconcha japonica Ishizaki, 1968. 19. Right lateral view of adult female specimen. 20.
Left lateral view of juvenile specimen. All scale bars are 100 μm.

11Fig. 3. SEM images of ostracods from the Pleistocene Ogushi Formation, Amakusa, Kyushu, Japan. 1, 2. Loxoconcha japonica
Ishizaki, 1968. 1. Left lateral view of juvenile specimen with ventral alate ridge. 2. Right lateral view of juvenile specimen. 3–5.
Loxoconcha kitanipponica Ishizaki, 1971. 3. Right lateral view of adult male specimen. 4. Left lateral view of adult female
specimen. 5. Left lateral view of juvenile specimen. 6. Loxoconcha pulchra Ishizaki, 1968, left lateral view of juvenile specimen.
7–11. Loxoconcha uranouchiensis Ishizaki, 1968. 7. Left lateral view of adult male specimen. 8. Right lateral view of adult malespecimen. 9. Left lateral view of adult female specimen. 10. Right lateral view of adult female specimen. 11. Left lateral view ofjuvenile specimen. 12, 13. Neomonoceratina delicata Ishizaki et Kato, 1976. 12. Right lateral view of adult specimen. 13. Leftlateral view of juvenile specimen. 14. Neonesidea sp., right lateral view of juvenile specimen. 15. Paradoxostoma setoense
Schornikov, 1975, fragmented valve, left lateral view of juvenile specimen. 16. Parakrithella pseudadonta (Hanai, 1959), rightlateral view of adult male specimen. 17. Perissocytheridea inabai Okubo, 1983, left lateral view of juvenile specimen. 18–20.
Pistocythereis bradyformis (Ishizaki, 1968). 18. Left lateral view of adult male specimen. 19. Left lateral view of juvenile specimen.
20. Right lateral view of juvenile specimen. All scale bars are 100 μm.

12Fig. 4. SEM images of ostracods from the Pleistocene Ogushi Formation, Amakusa, Kyushu, Japan. 1, 2. Pistocythereis
bradyformis (Ishizaki, 1968). 1. Left lateral view of juvenile specimen. 2. Right lateral view of juvenile specimen. 3–5.
Pistocythereis bradyi (Ishizaki, 1968). 3. Right lateral view of adult female specimen. 4. Left lateral view of adult male specimen. 5.
Left lateral view of juvenile specimen. 6, 7. Pontocythere kashiwarensis (Hanai, 1959). 6. Left lateral view of adult specimen. 7.
Left lateral view of juvenile specimen. 8. Pontocythere miurensis (Hanai, 1959), right lateral view of juvenile specimen. 9.
Pontocythere subjaponica (Hanai, 1959), right lateral view of adult female specimen. 10–13. Spinileberis quadriaculeata (Brady,
1880). 10. Left lateral view of adult female specimen. 11. Left lateral view of adult male specimen. 12. Right lateral view of adultmale specimen. 13. Left lateral view of juvenile specimen. 14. Schizocythere kishinouyei (Kajiyama, 1913), right lateral view ofjuvenile specimen. 15. Semicytherura kazahana Yamada et al., 2005, left lateral view of adult male specimen. 16. Hemicytherura
tricarinata Hanai, 1957, left lateral view of juvenile specimen. 17, 18. Semicytherura miurensis (Hanai, 1957). 17. Right lateralview of adult male specimen. 18. Left lateral view of juvenile specimen. 19. Semicytherura sp., right lateral view of adult specimen.
20. Trachyleberis niitsumai Ishizaki, 1971, left lateral view of adult male specimen. All scale bars are 100 μm.

13Fig. 5. SEM images of ostracods from the Pleistocene Ogushi Formation, Amakusa, Kyushu, Japan. 1, 2. Trachyleberis niitsumai
Ishizaki, 1971. 1. Left lateral view of juvenile specimen. 2. Right lateral view of adult female specimen. 3–5. Xestoleberis hanaii
Ishizaki, 1968. 3. Left lateral view of juvenile specimen. 4. Right lateral view of juvenile specimen. 5. Right lateral view of juvenile
specimen. 6. Pistocythereis bradyformis (Ishizaki, 1968), enlargement of mid-anterior area of fig. 4.1. 7. Pistocythereis bradyi(Ishizaki, 1968), enlargement of mid-anterior area of 4.5. 8. Schizocythere kishinouyei (Kajiyama, 1913), enlargement of central
area of fig. 4.14. 9. Semicytherura miurensis (Hanai, 1957), enlargement of mid-posterior area of fig. 4.17. 10. Xestoleberis hanaii
Ishizaki, 1968, enlargement of central area of fig. 5.4. 11. Kotoracythere inconspicua (Brady, 1880), enlargement of central areaof fig. 2.11.

14

Remarks – The type materials (holotype, carapace; paratype,
carapace) were recovered from the Recent beach sand from

Loxoconcha harimensis Okubo, 1980, p. 422–424, figs. 16,

about 1km NE of Akase Station, Uto Peninsula, Kumamoto

19g–19l.

Prefecture, Kyushu Island (Hanai, 1957b). Okubo (1980)

Remarks – This species was described by Okubo (1980)

described female appendages and male copulatory organfrom the sample of the rocky shores of intertidal zone, Aioi,

from the intertidal zones of the Seto Inland Sea. Our figured

Hyogo Prefecture, the Seto Inland Sea, Japan. Okubo (1980)

specimens (Pl. 2, fig. 15; Pl. 6, fig. 3) are juvenile the species.

illustrated transmitted valves of male and all appendages

Kamiya (1988a) figured the life habitat of the species as

including male copulatory organ although he did not show

sandy bottom under Zostera bed in Aburatsubo Cove, central

SEM image of this species. Kamiya (1988a) figured the life

Japan.

habitat of this species (he figured as L. sp.) as sandy bottom
under Zostera bed in Aburatsubo Cove, central Japan.
Genus Semicytherura Wagner, 1957
*Loxoconcha japonica Ishizaki, 1968
*Semicytherura kazahana Yamada et al., 2005

Figs. 2.19, 2.20, 3.1, 3.2

Fig. 4.15
Loxoconcha japonica Ishizaki, 1968, p. 28, 29, pl. 2, fig. 1, pl.
Semicytherura kazahana Yamada et al., 2005, p. 251–255,

6, figs. 10-12.

figs. 2C, 6, 7.

Remarks – The appendages including male copulatory

Remarks – Yamada et al. (2005) described this species fromorgan were described by Okubo (1980) from the rocky shore

the intertidal zone of Aburatsubo Bay, Kanagawa Prefecture,of intertidal zone, near Mukaishima Marine Biologicalcentral Japan. They also described appendages including

Station, Hiroshima University, Hiroshima Prefecture, Seto

male copulatory organ and number of pore canals of theInland Sea, Japan. The life cycle and microhabitat (typical

species.

phytal habitat) of this species has explored by Kamiya (1988a,
1988b, 1988c, 1989a, 1989b) in detail. The biogeograpghical

Semicytherura miurensis (Hanai, 1957) (Hanai, 1957b inreference)

distribution of L. japonica and its morphological variation
were discussed by Tanaka and Ikeya (2002).

Figs. 4.17, 4.18, 5.9
Loxoconcha kitanipponica Ishizaki, 1971
Cytherura miurensis Hanai, 1957, p. 18, 19, pl. 2, figs. 4a, 4b,

Figs. 3.3–3.5

text-figs. 4a, 4b.
Remarks – Hanai (1957b) described this species from the

Loxoconcha kitanipponica Ishizaki, 1971, p. 87, pl. 5, fig. 4,

Recent beach sand from shore behind an Imperial villa,pl. 6, figs. 11, 12, pl. 7, fig. 10.

Hayama-machi, Kanagawa Prefecture, Japan.

Remarks – Ishizaki (1971) described this species from the
Recent sandy mud collected from Aomori Bay, northern

Semicytherura sp.

Honshu Island, Japan (21 m in water depth).

Fig. 4.19*Loxoconcha pulchra Ishizaki, 1968
Remarks – The figured specimen is an undescribed species

Fig. 3.6of the genus Semicytherura.
Loxoconcha pulchra Ishizaki, 1968, p. 31, pl. 1, fig. 16, pl. 7,
Family Loxoconchidae Sars, 1926

figs. 19, 20.

Genus Loxoconcha Sars, 1865

Remarks – This species was described by Ishizaki (1968)
from Uranouchi Bay, Kochi Prefecture, Shikoku Island,*Loxoconcha harimensis Okubo, 1980

Japan. Appendages including male copulatory organ were

Figs. 2.16–2.18

described by Nakao and Tsukagoshi (2002) from sandy

15bottoms of the Obitsu River estuary, Boso Peninsula, central

from the muddy bottom sediment in the Seto Inland Sea,

Japan.

Japan at a depth of 27.5 m. The appendages including male
copulatory organ were described by Okubo (1978) from the
Loxoconcha tosaensis Ishizaki, 1968
Figs. 2.12–2.15

sand-mud sediment in subtidal and intertidal zone from the
Seto Inland Sea, Japan.

Loxoconcha tosaensis Ishizaki, 1968, p. 31, 32, pl. 2, fig. 3, pl.

Family Leptocytheridae Hanai, 1957(Hanai, 1957a in

7, figs. 6–9.

reference)

Remarks – Loxoconcha tosaensis was described from theGenus Callistocythere Ruggieri, 1953

Uranouchi Bay by Ishizaki (1968) on the basis of empty
valves. On the basis of valve shape and ornamentation,

Callistocythere hayamensis Hanai, 1957 (Hanai, 1957a in

Loxoconcha tosaensis is probably a junior synonym ofreference)

Loxoconcha bispinosa Kajiyama, 1913. However, Kajiyama

Figs. 1.17–1.20(1913) did not designate type specimen and also were notdeposited his type specimens. We use L. tosaensis as

Callistocythere hayamensis Hanai, 1957, p. 455, 456, pl. 7,

justifiable taxonomic name. Soft parts are only described

figs. 2a–2d.

antennule and male copulatory organ by Kajiyama (1913).

Remarks – Hanai (1957a) described this species from the

Kamiya (1988a) figured the life habitat of this species (heRecent beach sand from shore behind an Imperial villa,

figured as L. bispinosa) as sandy bottom under Zostera bed in

Hayama-machi, Kanagawa Prefecture, Japan.

Aburatsubo Cove, central Japan.
Callistocythere hotaru Yajima, 1982
*Loxoconcha uranouchiensis Ishizaki, 1968

Fig. 1.16

Figs. 3.7–3.11
Callistocythere hotaru Yajima, 1982, p. 190, 191, pl. 11, figs.
Loxoconcha uranouchiensis Ishizaki, 1968, p. 32, pl. 7, figs.

5, 6, text-figs. 14-1, 14-2.

2, 3.

Remarks – This species was described by Yajima (1982)

Remarks – Appendages including male copulatory organfrom the Early Pleistocene Kiyokawa Formation (MIS7.4 towere described by Okubo (1980) from sandy bank under7.3), near Yokota railway station, Hirakawa-machi, Chiba

Zostera from the Seto Inland Sea. The life cycle andPrefecture, central Japan.

microhabitat (typical sandy bottom of Zostera bed) of thisspecies has explored by Kamiya (1988a, 1988b, 1988c,

Family Pectocytheridae Hanai, 1957（Hanai, 1957a in

1989a, 1989b) in detail. Recently, Le et al. (2016) describedreference）

L. yoshidai from sandy beach at Bise, Motobu Peninsula,

Genus Kotoracythere Ishizaki, 1966

Okinawa Island, Japan. L. uranouchiensis differs from L.
yoshidai by having widely arched postero-ventral margin,*Kotoracythere inconspicua (Brady, 1880)

more inflated lateral outline and no distinct muri diverging

Figs. 2.11, 5.11

from the mid-anterior area to posteriorly.
Cythere inconspicua Brady, 1880, p. 70, 71, pl. 13, figs. 1a–
Genus Cytheromorpha Hirschmann, 1909

1d.
Remarks – This species was described by Brady (1880)*Cytheromorpha acupunctata（Brady, 1880）

from sand material from Torres Straits (284 m in water

Fig. 2.1

depth). Complete appendages including female copulatoryorgan were described by Wouters (2003) from the intertidal

Cythere acupunctata Brady, 1880, p. 68, pl. 14, figs. 1a–1h.

zone of the Cape Verde Islands, Atlantic Ocean. The

Remarks – The specimen was described by (Brady, 1880)

polymorphism, biogeography and fossil record of this species16

were discussed by Witte and Van Harten (1991).

Cythere nishinipponica Okubo, 1976: p. 113–117, figs. 1–3.
Remarks – This species was described by Okubo (1976a)

Family Cobanocytheridae Schornikov, 1975
Genus Cobanocythere Hartmann, 1959

from various intertidal zone from the Seto Inland Sea, Japan.
Okubo (1976a) also figured and described appendages.

Cobanocythere sp.

Genus Spinileberis Hanai, 1961 (Hanai, 1961b in reference)

Fig. 2.2*Spinileberis quadriaculeata (Brady, 1880)
Figs. 4.10–4.13

Remarks – This family consisted only interstitial species
based on a molecular phylogenetic analysis using 18S rDNA

Cythere quadriaculeata Brady, 1880: p. 86, 87, pl. 22,(Higashi, 2010).

figs.2a-d, pl. 25, figs. 4a-d.
Remarks – This species was described by Brady (1880)

Family Xestoleberididae Sars, 1928

from the Seto Inland Sea, Japan at a depth of 27.5 m. The

Genus Xestoleberis Sars, 1865

description of full appendages was by Okubo (1978) fromsand-mud shores in subtidal and intertidal zones of Seto

Xestoleberis hanaii Ishizaki, 1968

Inland Sea, Japan.

Figs. 5.3–5.5, 5.10
Family Schizocytheridae Howe, 1961 (in Benson et al.,
Xestoleberis hanaii Ishizaki, 1968: p. 41, 42, pl. 9, figs. 1, 2.

1961)

Remarks – The short life-cycle (about one month to reach

Genus Schizocythere Triebel, 1950

adult) of this species was noted by Ikeya and Kato (2000).

*Schizocythere kishinouyei (Kajiyama, 1913)

The male copulatory organs of the species were figured by

Figs. 4.14, 5.8

Sato and Kamiya (2007), and two morphological types(L-type and I-type) were reported around Japan.

Cythere kishinouyei Kajiyama, 1913: p. 11, figs. 61–63.
Remarks – Kajiyama (1913) described this species fromFamily Krithidae Mandelstam, 1958 (in Bubikjan, 1958)

Misaki, Kanagawa Prefecture, Japan on the basis of three

Genus Parakrithella Hanai, 1961 (in Benson et al., 1961)

appendages and male copulatory organ. However, Kajiyama(1913) did not designate type specimen and also were not

Parakrithella pseudadonta (Hanai, 1959)

deposited his type specimens. Hanai (1970) described all

Fig. 3.16

appendages including male copulatory organ from medium
sand from beach in front of the Imperial Villa, Kanagawa

Neocyprideis pseudadonta hanai, 1959: p. 300, pl. 17, figs. 5

Prefecture, Japan.

–9, text-figs. 2a, 2b.
Remarks – The appendages with male copulatory organ

Genus Neomonoceratina Kingma, 1948

were described by Okubo (1976b). Tanaka (2016) compared

Neomonoceratina delicata Ishizaki et Kato, 1976

the appendages of this species between female and male, he

Figs. 3.12, 3.13

also mentioned this species living from 0 m to 17.5 m inwater depth.

Neomonoceratina delicata Ishizaki et Kato, 1976: p. 136–
138, pl. 3, figs. 7–10, pl. 4, figs. 1–3, text-fig. 8.
Family Cytheridae Baird, 1850

Remarks – Ishizaki and Kato (1976) described this species

Genus Cythere O. F. Müller, 1785

from the Late Pleistocene (MIS 5) Furuya Mud from*Cythere nishinipponica Okubo, 1976 (Okubo, 1976a in

ShizuokaPrefecture,

centralJapan.

The(paleo-)reference)biogeographical distribution of the species was mentioned by

Fig. 2.5

Irizuki et al. (2009). The occurrences of this species from theOgushi Formation is the most southern fossil record during

17

the Late Pleistocene (MIS 7) (Kawano et al., 2011). Present

sand from the shore in front of the Imperial Villa at Hayama,

distribution of this species from Java Seas to Ryukyu Islands

Kanagawa Prefecture, Japan. Okubo (1977) described(till Tokara Straight) via the coast of China and northern

appendages with male copulatory organ of this species from

Vietnam (Irizuki et al., 2009; Tanaka et al., 2009).

muddy sand under Zostera beds from the Seto Inland Sea,
Japan.

Family Cytherideidae Sars, 1925
Genus Perissocytheridea Stephenson, 1938

Family Trachyleberididae Sylvester-Bradley, 1948

Perissocytheridea inabai Okubo, 1983

Genus Trachyleberis Brady, 1898

Fig. 3.17

Trachyleberis niitsumai Ishizaki, 1971
Figs. 4.20, 5.1, 5.2

Perissocytheridea inabai Okubo, 1983: p. 410.
Remarks –Okubo (1983) described this species as new

Trachyleberis niitsumai Ishizaki, 1971: p. 93, pl. 5, fig. 3, pl.

species based on his previously published literature (Okubo,

6, fig. 10, pl. 7, fig. 9.

1979). Okubo (1979) reported this species from mud

Remarks –Ishizaki (1971) reported this species from Aomori

sediment dredged at a depth of 15 m from the Seto Inland

Bay, northern Honshu Island, Japan. The biogeography andSea, Japan.

type species were mentioned by Brandão et al. (2013).

Family Cushmanideidae Puri, 1974 (in Hartmann and Puri,

Genus Bicornucythere Schornikov and Shajtarov, 1979

1974)

*Bicornucythere bisanensis s.l.(Okubo, 1975) (Okubo,

Genus Bicornucythere Schornikov and Shajtarov, 1979

1975b in reference)

Pontocythere kashiwarensis (Hanai, 1959)

Figs. 1.9–1.14

Figs. 4.6, 4.7
Leguminocythereis bisanensis Okubo, 1975: p. 26–30, figs. 2,
Cushmanidea kashiwarensis Hanai, 1959: p. 297, pl. 17, figs.

3.

1–4.

Remarks –This species was described by Okubo (1975)

Remarks – Hanai (1959) described this species from a sandfrom mud sediment 20 m off the coast of Shibukawa,sediment from the shore of Kashiwara, about 200 m

Tamano City, Okayama Prefecture, the Seto Inland Sea,

southeast of Dozanto, Yamaga, Ashiya Town, Fukuoka

Japan. He also described appendages including male

Prefecture, Japan.

copulatory organ. According to Abe (1988), there are fourmorpho-types (A, M, P, G type) around Far East. Our figured

Pontocythere miurensis (Hanai, 1959)

specimen would be classified A type of Abe (1988).

Fig. 4.8
Genus Pistocythereis Gou, 1983 (in Gou et al., 1983)
Cushmanidea miurensis Hanai, 1959: p. 299, pl. 16, figs. 7–

Pistocythereis bradyformis (Ishizaki, 1968)

10, text-figs. 1a, 1b.

Figs. 3.18–3.20, 4.1, 4.2, 5.6

Remarks – This species was described by Hanai (1959)
from beach sand from the shore in front of the Imperial Villa

Echinocythereis bradyformis Ishizaki, 1968: p. 40, pl. 8, fig.

at Hayama, Kanagawa Prefecture, Japan.

4.
Remarks – This species was described by Ishizaki (1968)*Pontocythere subjaponica (Hanai, 1959)

from the Uranouchi Bay, Shikoku Island, Japan, on the basis

Fig. 4.9of left valve. Okubo (1979) re-described this species as maleof E. bradyi (Ishizaki, 1968) from subtidal zone of muddy

Cushmanidea subjaponica Hanai, 1959: p. 298, 299, pl. 16,

shores from the Seto Inland Sea, Japan. Okubo (1979)

figs. 4–6.

regarded E. bradyformis (Ishizaki, 1968) as male of E. bradyi.

Remarks – Hanai (1959) described this species from beach

However, on the basis of presence of ridges running from

18

anterior area to postero-ventral area in E. bradyformis, themale and female designated by Okubo (1979) is different

Coquimba ishizakii Yajima, 1978: p. 397, 398, pl. 49, figs. 4a

species. Although Okubo (1979) described appendages of E.

–4c, text-fig. 7, figs. 3a, 3b.

bradyi, we cannot identify his figured appendages are

Remarks – This species was described by Yajima (1978)

Pistocythereis bradyi or P. bradyformis.

from the Late Pleistocene Yabu Formation, Sengen Shrine,
Kisarazu City, Boso Peninsula, central Japan.

Pistocythereis bradyi (Ishizaki, 1968)
Figs. 4.3–4.5, 5.7
Acknowledgements
Echinocythereis bradyi Ishizaki, 1968: p. 40, pl. 9, fig. 17.

I (G.T.) dedicate this paper to the late Professor Emeritus

Remarks – This species was described by Ishizaki (1968)

Noriyuki Ikeya (Shizuoka University) and his wife Chieko

from the Uranouchi Bay, Shikoku Island, Japan, on the basis

Ikeya (Makinohara City, Shizuoka) for providing me theof left valve. Okubo (1979) re-described this species as

original sediment.

female of E. bradyi (Ishizaki, 1968) from subtidal zone of
muddy shores from the Seto Inland Sea, Japan. See remarks

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