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Chapter 73. Some Quaternary ostracods of the Pannonian Basin, with a review of a few neglectoida

Chapter 73. Some Quaternary ostracods of the Pannonian Basin, with a review of a few neglectoida

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N.KRSTIC



1064



TABLE1

PLEISTOCENE



OSTRACODS

OF THREE BOREHOLES

(156200 m deep)



MIDDLE



'i

v)



+,



f



4



E

0)



8



.z



c)



3



Eucypris pigra

Metacypris crodata

Eucandona lewanderi

Candonopsis kingsleii

Candona candida

Candona weltneri

Cyclocypris laevis

Pseudocandona compressa

Ilyocypris monstrifca

Cyclocypris ovum

Cypris ophthalamica

Fabaefromiscandonafabaeformis

Hungarocypris madaraszi

Fabaeformiscandonaprotzi

Cyrpidopsis vidua

Cyclocypris serena

Pseudocandona marchica

Cyclocypris cf. ovum

Paracandona euplectella

Ilyocypris gibba

Paralirnnocythere compressa

Slerrocypris? clavata

Cypris pubera

Cyprois marginata

Cyclocypris globosa

Eucandona balatonica

Stanchevia crassa

Ilyocypris aff. bradyi

Herpetocypris indet.

Scottia browniana

Candona permanents*

Ilyocypris soka6i*

Scottia tumida

Ilyocypris salebr. salebrosa

Virgatocypris cf. elongata

Cyclocypris taubachensis

Ilyocypris caspiensis

Limnocythere aE. inopinata

Ilyocypris bijdicata

Candona banatica*

Limnocythere aff. stationis

Candona cf. montenegrina

Ilyocypris inermis minuta*

Cyclocypris diebeli



middle

cycle



upper

cycle



single

cycle

10 11



1



+

+

+

+++

/+I +



++

+

+

+

+

+

++

+ +

+

+

I+/



++

+

/+I +



+

+



PLIOCENE



LOWER



+



++



+

+++

++

++

+

+

+

+

+



10 11



+

+

+

+

+

+

+

+

+

++

+

+

+

+

+

+

+

+

+



1



10 11 1



UPPER



lower

cycle

10



11



ultim. penulcycle timate

cycle

1



+

+

+

+

++

+

++

+ +++

+

+

+

I+/

/+I



I+/



+

+



+



+



+

+



+



+

+ + +



+



+

+ ++



10 1 10 1



1



+



++



/+I



I+/



+

+++

?



+



/?I



+ i



+

+

+ + + +

+ + I+/

+

+

+ +

+

+



+



+

?



?



+



/+I

?



++

+

+

+



+

+

+



+

+ +



+

(Continued)



Quaternary Ostracodr of Pannonian Basin 1065



TABLE1-Continued.

10 1 1



!

UY



'3



*



Cyprinotus magnus*

Ilyocypris aff. biplicatal n.sp.1

Zlyocypris nsp. /cylindrical/

Cyprinotus n. sp. /smooth/

Cypridoptis aff. newtoni

Cypris sp. ltuberculate species/

Typholocypris sp.



1



10 11 1 10 1 1



+



Ilyocypris gr. decipiens

Pseudocandona aff. crispata

p)

Candona sp. /hi& neglectoid/

Zlyocypris gr. gibba /small/

.- Eucypris cf. famosa

Cypridopsis aff. vidfra

Cypria sp. /triangulate species/

Ilyocypris gr. bradyi /small/

New species and subspecies described from this region (Krsti6, 1985).



1



10 11



1 10 1 10



+



+



1-1



+++



+



+ + +



+



+

+



++



+

+

+

+

+

+



+



Zlyocypris from the gibba group and bradyi group etc. It is not possible to establish for certain

which species appear at the Pliocene-Pleistocene boundary. In Table 1 only three boreholes are

shown (BT-10, 2-11 and JT-1), in which ostracods were carefully studied and other evidence was

also complete. Two of them reached the Pliocene (depth of boreholes is 150 m.), while the third

one (with a depth of 200 m) did not.

Three main sedimentary cycles belong to the Lower Pleistocene s.1. (Boeckhi Beds). According

to the climatic theory, they should be Biber-Danube (Tiglian?) and Danube, Danube-Gum

(Waalian?) and Gunz, and Gum-Mindel (Cromerian?) and Mindel in age. Apart from Viviparus

boeckhi and Bithynia crassi testa, which are present mostly in the lower part of the Lower Pleistocene, there are micromammals-Arvicolagreeni (Upper Biharium) and Microtus gr. arvalis-agrestis

(uppermost Upper Biharium-Upponium to early Oldenburgium) showing affinities to Mindel.

The different thicknesses of the same cycles in different boreholes depends on the tectonics-slow or

fast sinking or even uplift(?) as well.

In the ostracod associations there are plenty of species which are still living as well as extinct

ones. At present it is not possible to name key ostracods. A possible key-species could be Zlyocypris malezi (SokaE, 1978, determined as Middle Pleistocene in a few cycles, some of which should

be Lower Pleistocene in age), and some other Ilyocypris species from the bradyi group. Cyprinotus

magnus (KrstiE, in press) has been found in the Waalian?-Gum. The genus Cyprinotus is not common in the Quaternary of the Pannonian basin, but there are more Cyprinotus in the rheophile

environment of the lower cycle (Tiglian?-Danube) with its wanner climate. The first records of

Ilyocypris sokaEi and Virgatocypris are from the lower cycle of Lower Pleistocene. Virgatocypris

is a Tertiary relic (known from the Middle Miocene).

The whole association from the three bore holes is given in Table 1. Here the change between

rheophile and stagnophile species through a single sedimentary cycle should be noted. In the

lowermost part of every cycle, where Lithoglyphus and similar molluscs representative of a highenergy environment (coarse sand, sometimes with pebbles) are present, there are no ostracods.

Just above it, in the moderate energy environment (medium to fine-grained sand), Scottiu browniana is most numerous, and sometimes forms a monospecific assemblage. Towards the top of the

ideal cycle, Scottia is slowly replaced by other ostracods, mostly Candona, Pseudocandona, Cyclocypris (mainly C. laevis), Zlyocypris and others indicating a lacustrine environment. This pic-



1066 N.rn1-16



TABLE

2

ENVIRONMENT



A



Q



Ostracods of the

MIDDLE PLEISTOCENE

in SE of Pannonian basin



NE BaEka

SF S1 S



Mixtacandona transleithanica

Typhlocypris cf. szocsi

Candona aff. breuili

Typhlocypris cf. hvarnensis

Mixtacandona botosaneanui

Typhlocypris cf. eremita

Pseudocandona cf. profundicola

Potamocypris zschokkei

Cypridopsissubterranea nermanica



Seottia browniana

F Ilyocypris salebrosa

Eucypris pigra

Cytherissa Iacustris

Metacypris cordata

Seottia tumida

Eucandona Ievanderi

Cyclocypris taubachensis

SI Candona permanenta

Ilyoeypris decipiens baczkae

Candona banatica

Limnocythere aff. inopinata

Candona cf. wegelini

Ilyocypris inermis minuta

Candona candida

Cyclocypris Iaevis

Candona weltneri obtusa

Ilyocypris biplicata

Candona cf. neglecta

Pseudocandona cf. crispata

Candona cf. candida

Ilyocypris monstrifca

Candona cf. paionica

Ilyocypris sokaEi

Cyclocypris cf. serena

Candona rawsoni

Pseudocandona compressa

Candona loieki

S Ilyocypris aff. bradyi ldiv.1

Notodromas monaeha

Virgatocypriscf. elongata

Fabaeformiscandonafabaeformis

Cypira ophthalamica

Candona cf. montenegrina

Candona lobipes

Limnocythere &. stationis

Pseudocandona cf. insculpta

Cyclocypris ovum

Fabaeformiscandonaprotzi

Limnocythere cf. baltica

Candonopsis kingsleii



NW Banat

SF S1 S

0



N E Banat

SF SI S



Middle

Banat

SF SI S



Srem

SF Sl S



0



.



. .

0



.

~-



0



0

0



.



0



0



0



0 ,



0 0



0

0



0 0 . .

0 0 . 0 0 0

0



0 0

0 0

0 . 0

0 . 0 .

0 0

0

0 .

0

0 0 0 0 0



0

0



0

0



0 0 . .

0 . 0 0

0 .



0



0



0 . 0 0



0



0



0

0 .

0 . 0



0



0 0

0

0



.

0



0



0 0



0



0 .

0 .



0



0



0 0

0 . .



0 .

0 0



0



0



.

0



0



0 .

0 .



.



0



0 0

0



.



0

0



0 . 0 0



.



0

0 .



0 .

0



. .

0



0

0

0



0



0.

0



0



0 0

0 0



0



0



.



00..



0



0



.



0



0

0



0



0



*



0



0



0



0

- 0

0 0



0



0

0

0



0 0

0 0

0



0



0 0

0

0 0 0



. .



0



0

0 . .

0



.



.

0



(Continued)



Quaternary Ostracods of Panrwnian Basin 1067



TABLE2-Continued.

~



ENVIOstracods of the

Middle

RONMIDDLE PLEISTOCENE

NE BaEka NW Banat NE Banat

Banat

Srem

SF S1 S SF S1 S SF S1 S SF S1 S SF S1 S

MENT

in SE of Pannonian basin

Darwinula stevensoni

Ilyocypris aff. gibba

0

Herpetocypris reptans

*?

*?

01

*?

0

Candona weltneri

0

0

0 .

0 0

S Cyclocypris cf. ovum

0 .

0 0

0 0

0 0

0

Fabaeformiscandona hyalina

0

Hungarocypris madaraszi

0

Cypridopsis vidua

0

Pseudocandona marchica

0 . 0 0 .

0 .

0 0

Paracandona euplectella

0

0

0 0

Pseudocandona albicans

0

0 0

Ilyocypris gibba

0

0 0

0 .

Physocypria cf. kraepelini

P Cyprinotus buIgaricus

0

Paralimnocythere compressa

0 .

0

0

0 0

0

Cyclocypris diebeli

Sclerocypris? clavata

. o o

0 0

Cypris pubera

0 0

0 0

0 0

Stanchevia crassa

0

Candona sp. /gigant/

Pp Eucandona balatonica

0 0

0

Cyclocypris globosa

* o

0

0 0

0 .

Cyprois marginata

0

number of positive samples

1

9 7 11 13 27 9

1 60 2 26 44 4

5 14

Explanation: 0 > 10%; 0 2-10%;

< 2% most in any of the samples. A=underground species, Q=spring

species, F=tluviatile species, Sl=stagnophiIe/lacusMnelspecies, S=stagnophile species, P=

palustrine species, Pp=species of periodic swamp.



.

.

..

.

. .

. .



. . .



. .



ture is repeated in every cycle. It is also seen in the Middle Pleistocene, but not in the Upper Pleistocene because Scottia browniana has disappeared.

The Middle Pleistocene (MakiS Beds) is the most widespread unit at the surface in the Pannonian basin, although it is represented by a single sedimentary cycle. Consequently, it was possible

to study it in detail and to distinguish three ecological groups of assemblages: fluvio-lacustrine,

lacustrine and stagnophile. In order to distinguish these two ecologically, key-species were used :

Scottia browniana and Cytherissa lacustris, the basis being Absolon's species distribution (1973).

From an ecological point of view, Scottia browniana appears in moderate energy environments.

The second ecologically important species, Cytherissa lacustris, which now lives in the deeper

parts of lakes, was used to distinguish a true lacustrine biofacies. In cases where C.lacustris was

absent (first two columns of Table 2), the absence of any palustrine species suggested a stagnant

biofacies, mainly lacustrine but from the shallow parts of the lakes (the true palustrine biofacies

is not yet known from the Middle Pleistocene of the Pannonian basin). The presence of assemblages

with Typhlocypris, Mixtacandona and the like, need to be explained since they should belong to

the nearshore environment. An explanation is also needed for the presence of rare species such as

Zlyocypris salebrosa Stepanaytis, Virgatocypris cf. V . elongata (Schneider), Candona rawsoni Traessler and Caclocypris diebeli Absolon, as well as Cyprois marginata, Notodromas monacha and even

Pseudocandona albicans. It is possible that they are climatically conditioned as the first two belong

to warm, and the others to cold, climatic zones. Stratigraphically, the cycle described here belongs



1068



N.KRSTIC



to the great Mindel-Riss interglacial period. There are many records of mammals such as Elephas

trogontherii from it. At the upper boundary of this cycle, many species known from the Lower

Pleistocene and even Upper Pliocene, disappear, including Scottia browniana, S. tumiria,

Virgatocypris (as a genus), Candona permanenta, Zlyocypris salebros salebrosa, Z. sokaEi and

other ostracods, as well as some molluscs like Pisidium clessini.

The Upper Pleistocene is the second most widespread unit in the Pannonian basin. Unfortunately for ostracod research, it consists of aeolian and swampy loess, the latter with a very scarce

microfauna. Riss loesses (not yet documented palaeontologically) are developed only in the southernmost part of the Pannonian basin which at that time was sinking and was not much exposed

to later erosion. The Riss-Wurm interglacial (Eemian) sediments on the southern rim of the

Pannonian basin are known as the Bulbulder terrace sediments. They consist of reworked loesslike silt, with rare, well rounded (many times reworked) pebbles and, near the Neogene limestone

on the bank, intercalcations of breccia. Further north, in BaEka there are also some records of rare,

well-rounded pebbles in the base of the Wurm loess and above the Middle Pleistocene. The Wurm

silt is spread out on wide loess sheets. It seems that in Wurm-2, the climate was more humid so

that small water bodies had grown bigger and had ostracods living in them, not only molluscs as

was the case before and after this time. The picture is complicated by synsedimentary and later

tectonic movements which produced the fluvio-lacustrine Szentes unit, preserved in some places,

and of proven Wurm-2 age.

Ostracods are very rare in the Upper Pleistocene. Scarce finds of solitary valves in swampy loess

are of little help in reconstructing the biotope. The more or less rich ostracod associations were

only found in the level attributed to Wurm-2. There two types of associations could be distinguished, namely the Candona-Zlyocyprisassemblage and the Typhlocypris-P. albicans assemblage.

The Candona-Zlyocyprisassemblage belongs to a kind of lacustrine biotope (the middle part of the

Szentes unit). Together with Elephas primigenius of the Wurm-2 evolutionary level, the ostracod

association consists of: Candona paionica, Zlyocypris biplicata, Eucandona levanderi, Zlyocypris

monstrifica, Limnocythere aff. L. inopinata, Ilyocypris decipiens. At the top of the cycle (started

by fluviatile crossbedded coarse sand with pebbles at the base), this association is slowly replaced

by an assemblage containing Paralimnocythere compressa, Eucandona balatonica, Cypris pubera

and Cyprois marginata, but Cyclocypris laevis, Candona paionica, C. fasciolata, C. candida, Pseudocandona compressa, Zlyocypris inermis, etc. are still present. The second assemblage, with Typhlocypris eremita, Pseudocandona albicans (parallela), Mixtacandona botosaneanui, M . transleithanica,

and also Ilyocypris gibba, Candona candida, Eucypris pigra and others, was found in the second

loess horizon, so it should also belong to Wurm-2. It is possible that this assemblage belongs to

small water bodies, perhaps small lakes. The species P . albicans could indicate a cold climatic

period, but the other representatives of the second association do not have clear climatic implications.

The Holocene sediments form a thin surface sheet about one metre thick. In origin they are

overbank fluviatile deposits and consist of silt which is rich in organic matter. Rarely and close

to the rivers, there are filled in old river. channels which contain plenty of ostracods in the silty

parts of the sequence, mainly sandy and pebbly at the base and silty at the top. The ostracod

assemblages consist of Candona paionica, C. candida, Eucandona levanderi, Pseudocandona marPLATEl-Female and male left valves. Figs. 1,2. Candona (Cundonu) neglectu Sars, Recent, Mavrovo spring (coll.

det. Petkovski). Fig. 3. Candona (Cundoncr) fasciolutu Petkovski, Wurm-2, Kikinda. Figs. 4, 5. Cundonu

(Candonu) cf. C. puionicu Petkovski-winter form, Holocene, Gloianj 4. male right valve. Figs. 6, 7. Cundonu

(Candona) cf. C.puionicu Petkovski-summer form, Holocene, Gloianj. Figs. 8, 9. Candona (Candonu) cf. C.

puionicu Petkovski Wurm-2, Kikinda. Figs. 10, 11. Condona (Candonu) cf. C. puionicu Petkovski, Middle

Pleistocene, Banatsko Karadjordjevo.



Quaternary Ostracodr of Pannonian Basin 1071



chica, P. compressa, Cypris pubera, Physocypria kraepelini, Cypria ophthalamica, Cypridopsis vidua,

Zlyocypris salebrosa carinata and others. Such an assemblage again indicates a lacustrine environment, defined as a river lake by geomorphological analysis. At the time when ostracods lived in it,

the lake was 1-3 m deep, as determined on the basis of the Charophyta. In the microfauna, warm

climate species are represented by Zlyocypris salebrosa carinata and Physocypria kraepelini (most

common species) and perhaps also by Eucandona levanderi,an abundant species in the Quaternary

of the Pannonian basin.

Candona neglecta and its allies are abundant in the Quaternary of the Pannonian basin. This is

a large group of species which is very similar in the form of their shells. Here its features will be

discussed and its relationships to the Recent representatives, a discussion that was initiated by Absolon (1978, p. 25-27).

Candona neglecta Sars is a southern species, described from Lake Garda in Italy. It has a beanshaped shell (Pl. 1, fig. 1) with a curvate, relatively high anterior part, and a moderately rounded

posteroventral one.

Candonafasciolata Petkovski, described from the mountain region on the Balkan peninsula,

is a form common in central and northern Europe. Its shape is somewhere between that of a bean

and a triangle, and it has a less curved posterior margin, a narrower rounded posteroventral margin

and a lower anterior than C. neglecta. The inflation of the carapace is a little bit more than that

of the previous form. The specimens from the cool Wiirm-2 (Pl. 1, fig. 3) are a little shorter than

the Recent ones.

Candona permanenta KristiE (1989, from the Lower-Middle Pleistocene, has an almost evenly

curved anterior margin (see P1.2, fig. 10). The posterior part of the ventral margin is clearly convex,

and the axis of posteroventral roundness directed much higher than in all previously discussed species. Otherwise, in shape it is closest to C. neglecta, but straighter whilst c . neglecta is somewhat

crescent-shaped.

Candona cf. C. neglecta, as described by Diebel and Pietrzeniuk (1978, p. 49, fig. 3), is also found

in the Pannonian basin in the sediments of the great Mindel-Riss interglacial period. It seems to

have developed from C. permanenta and in Tables 1 and 2 they are not separated. The main feature

of C. cf. C. neglecta is the low anterior part of the left valve and the deep ventral concavity.

Thus, the anterior part of the ventral margin (concavity) is parallel to the dorsal margin as in C.

neglecta, but more clearly so.

Candona aff. C. montenegrina Petkovski, another Quaternary member of the C. neglecta group,

is crescent-shaped (Pl. 2, fig. 7), because its anterior margin has marked infracurvature and the

axis of posteroventral roundness is directed downwards more than in any of previous species. It

is not related to C. montenegrina from Skadar Lake (Pl. 2, fig. 8) which has a straight carapace, but

the previous designation was not changed after studying comparative material. Candona aff. C.

montenegrina is closer to C. dedelica, also crescent-shaped, but shorter (PI. 2, fig. 1).

Candonapaionica Pektovski has a large rounded posteroventral margin and is not much inflated

(PI. 2, figs. 5,7,8, 10). It seems that the types from Dorjan lake are even more rounded posteroventrally.

Candona banatica Kristi6 (in press) is a relatively small and high species, easily distinguishable

PLATE2-Female and male left valves. Figs. 1,2. Canhnu (CGndonu) dedelica Petkovski, Recent, Ohrid lake (coU.

det. Petkovski). Figs. 3,4. Candona (Candona) nutronphila Petkovski, Recent, Elemir in Panonian basin.

Figs. 5,6. Candonu (Candona) altoides Petkovski, Recent, Gevgelia (coll. det . Petkovski). Fig. 7. Candona

(Candona) aff. C. montenegrinu Petkovski, Middle Pleistocene, BaEka Topola. Figs. 8, 9. Candonu (Curadom)

montenegrina Petkovski, Recent, Skadar lake(col1. det. Petkovski). Figs. 10,ll. Candonu (Candonu) permunenta

Krsti6, paratypes, Lower Pleistocene, borehole JT-1 from 65.15 m.



1072 N. KRSTIC



from the other members of the C. neglecfa group by the short angular concavity of the ventral

margin. It is described from the Middle Pleistocene, but it is also present in the Lower Pleistocene.



ACKNOWLEDGEMENT

Without the Recent comparative material of T. Petkovski it would have been impossible to

discuss the C. neglecfa group.



REFERENCES

Most of the references are in MILOJEVIC-KRAMZAR,

D. (1984).

Bibliography; In Stevanovid P., SokaE A., Krstib N., Gagib N. and Milojevib-KramfarD. Research of fossil and

Recent ostracodes in Yugoslavia and revue of the Palaeo, Meso and Neogeographic features of Southeastern

Europe. VII International Symposium on Ostracods. Additional reports. Zapisnici Srpskog geol. dt dtva

(Compte rendue de sciences geol. SOC. serbe), za 1983, Beograd.



OTHERREFERENCES

1973. Ostracoden aus einigen Profilen spat- und postglazialer Karbonatablagerungen in Mitteleuropa.

Mitt. Bayer Staatssamml. Palaont. hist. Geol., 13,47-94.

1978. Die Gattung Candona (Ostracoda) im Quartar von Europa. Rozpr. ceskosl. Akad. Ved, r. matem. Prir.

Ved, 88 (5). 76.

BODA, J. 1957. Stratigraphische Auswertung fossile Ostracoden aus Ungarn. Ann. Univ. Sci. Budapes., Sect. Geol., 1,

21-23.

DIEBEL, K. and PIETRZENIUK,E. 1978. Die Ostracodenfauna aus den jungpleistozanen (weichselkaltzeitlichen)Deckschichten von Burgtonna in Thuringen. Quartarpalaont., 3, 207-221.

KOLLMANN, K. 1960. Cytherideinae und Schulerideinae n. subfam. (Ostracoda) aus dem Neogen des ostl. Oesterreich.

Mitt. Geol. Ges. in Wien. 51, 89-195.

KRSTIC, N. (1985). Nove vrste kvartarnih ostrakoda iz Vojvodine (New specis of the Quaternary ostracodes from

Vojvodina). Radovi Geoinst., 18.

PETKOVSKI, T. 1959. Susswasserostracodesaus Jugoslavien VI. Acra Musei maced. scii nut., VI 3 (55), 53-75, Skopje.

SOKAC, A. 1978. Pleistocene ostracode fauna of the Pannonian basin in Croatia. Paleont. Jugosl., 20, p. 52.

SZELES, hi. 1968. Pleistozbe Ostracoden-Fauna aus der Bohrung Jaszladany-1. Foldt. Kozl., 98, ( 3 4 , 394-407.

ABSOLON, A.



-



Preliminary Notes on

the Japanese Miocene Ostracoda

MICHIKO

YAJIMA

Tokyo Seitoku Gakuen. Tokyo, Japan



ABSTRACT

During Early Middle Miocene, 16.5-15.5 Ma, shallow, warm water ostracods lived in the Palaeo-Setouchi Province (Shobara, Tsuyama and Mizunami) and in Northeast Japan (Kanazawa

and Sendai). The fauna has close affinities with that of the Pleistocene and Recent, distributed

along the Pacific coast of Southwest Japan. During Middle Miocene, 15.5-9 Ma, shallow cold to

temperate water ostracods became widespread in Northeast Japan (Sekinohana, Sugota and

Kamikoani). The fauna is similar to Pleistocene and Recent faunas distributed along the Japan

Sea and Pacific coasts in Northeast Japan. The existence of two faunas in the Middle Miocene,

an earlier warm and a later cold one, confirms recent findings of tectonic and palaeogeographical

studies.



INTRODUCTION

The biostratigraphy and chronology of the Japanese Miocene have recently been vigorously

investigated, and a precise time scale has become available (Tsuchi et al., 1981). Sediments older

than the Early Middle Miocene are very scarce in Japan. The sediments of the early Middle Miocene ranging from 16.5-15.5 Ma, Blow’s (1969) N 8 zone, are dominated by shallow marine facies

rich in mega- and microfossils. Geloina-bearing molluscan assemblages of intertidal facies demonstrate the existence of mangrove swamps. Other assemblages of tropical to subtropical, shallow marine molluscan fossils are also present. These sediments are succeeded by offshore muddy or diatomaceous sediments. They represent the beginning phase of a major transgression in Japanese

Neogene history. At this time a shallow marine basin, the Palaeo-Setouchi Province, developed in

the Chugoku area of Southwest Japan and the Mizunami area of central Japan (Text-fig. 1).

In the Middle Miocene, Southwest Japan was emergent, while in Northeast Japan deposition of

thick marine sediments took place (Text-fig. 2).

Although these Miocene sediments are rich in mega- and microfossils, studies of ostracod

faunas are rare. Ishizaki (1963) described a small fauna from the Sunakosaka Member of the

Yatsuo Formation, east of Kanazawa. Recently this member was correlated with the Kurosedani

Formation of Blow’s N 8 zone (Tsuchi, 1981). Ishizaki (1966) also reported ostracod faunas from

the Moniwa Member and from the Hatatate Formation of the Sendai area. Recently the Moniwa

Formation, once the Moniwa Member, was correlated with Blow’s N 8 zone and the Hatatate Formation with the N 9 to N 16 zones (Text-figs. 1,2). Hanai (1957) reported Hemicytherura kajiyamai

1073



1074



M.YAJIMA

130



135



140



145



TEXT-FIG.

l-Localities of the Japanese Miocene ostracod samples.



from the Shukunohora Sandstone (Blow’s N 8 zone) of Mizunami in the East Palaeo-Setouchi

Province, and stated (1977) that “some species of living warm water ostracods, such as Hemicytherura kajiyamai. Aurila sp. and Schizocythere kishinouyei, which settled in Japan in the Middle Miocene, have maintained a status quo in phenotype up to the present”. By 1977, 47 species of 28

genera were reported from the Japanese Miocene. Among these, 13 species of 11 genera are extant.

While investigating Pleistocene shallow warm water ostracods, questions arose concerning their

origin and their history. To clarify these, I studied Miocene ostracods from Shobara (lower sand

of the Bihoku Group), Tsuyama (Yoshino Formation), Mizunami (Shukunohora Sandstone),

Sekinohana (Togi Mud Formation), Sugota (Sugota Formation), and Kamikoani (Kamikoani

Formation) (Text-figs. 1, 2).



EARLYMIDDLE

MIOCENE-SOUTHWEST

JAPAN

The Palaeo-Setouchi (Palaeo-Inland Sea) sediments are distributed in the Chugoku area. During

the Early Middle Miocene, this area was covered by a shallow warm sea with many islands.

Shobara

In the Shobara Formation of the Bihoku Group, the only ostracods present are very rare

Cytherelloidea sp.



Tsuyama

The Yoshino Formation at Tsuyama is about 15 m thick, light brown sand in the lower part,



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