ISS N 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New Series

No.

175

Pal aeo ntological Society of Japan
Septem ber 30, 1994

Co-Editors

Tsunemasa Saito and Kei Mori

Language Editor

Martin Janal (New York)

Editorial Board
Shiro Hasegawa (Hokkaido University), Kunihiro Ishizaki (Tohoku University), Tomoki Kase
(National Science Museum), Toshiaki Maruyama (Yamagata University), Kei Mori (Tohoku University), Kenshiro Ogasawara (University of Tsukuba), Tsunemasa Saito (Tohoku University), Y okichi Takayanagi (Ishinomaki Senshu University), Kazushige Tanabe (University ofTokyo), Yukimitsu Tomida (National Science Museum), Kazuhiko Uemura (National Science Museum), Akira Yao(Osaka City University)

Officers for 1993-1994
President: Hisayoshi Igo
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Ikuwo Obata, Kenshiro Ogasawara, Tomowo Ozawa, Tsunemasa Saito, Yokichi
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Members of Standing Committee: Kenshiro Ogasawara (General Affairs), Tomoki Kase
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The fossil on the cover is lsocrinus (Chladocrinus) hanaii Oji, an Early Cretaceous(Aptian) crinoid, which was described from the Hiraiga Formation exposed at Haipe,
Tanohata-mura, Shimo-Hei County, Iwate Prefecture, Northeast Japan. (University
Museum of the University of Tokyo coil. cat. no. ME6950, paratype specimen, length
about II cm)

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Trans. Proc. Palaeont. Soc. Japan, N.S., No. 17S, pp.497-S20, I I Figs., September 30, 1994

973.

BATHYAL BENTHIC FORAMINIFERAL CHANGES DURING
THE PAST 210,000 YEARS: EVIDENCE FROMPISTON CORES TAKEN FROM SEAS SOUTH
OF ISHIGAKI ISLAND, SOUTHERNRYUKYU ISLAND ARC*XUEDONG XU
Department of Earth Sciences, Faculty of Science,
Kumamoto University, Kumamoto, 860
and

HIROSHI UJIIE
Department of Marine Sciences, University of the
Ryukyus, Okinawa, 903-01

Abstract. Benthic foraminiferal assemblages are studied using two piston cores,
RN87-PC4 and RN87-PCS, which were respectively raised from the central site (water depth:
2,488 m) and the outher edge (3,136 m) of the Sakishima Deep-Sea Terrace that is locatedbetween the southern Ryukyu Island Arc and Ryukyu Trench. Planktonic foraminiferal
0'180 stratigraphy reveals that RN87-PC4 reaches ~ I 10 Ka and RN87-PCS encompasses theperiod from ~I IS to ~210 Ka. Bolivina decussata, Abditodendrix pseudothalmanni,
Takayanagia delicata and Astrononion novozealandicum are characteristically dominant
throughout RN87-PC4, whereas Fursenkoina cedrosensis, Epistominella exigua, Epistominella levicula and Evolvocassidulina brevis are clearly richer in RN87-PCS. At present,
however, it cannot be decided as to whether these contrasting occurrences are due todifferences in age or in habitat reflecting different water depth. Alabamina? rugosa andPulleniella asymmetrica predominate in the oxygen isotope Stages Sand 7 (interglacial
episodes) in RN87-PCS. It is also suggested that a dominant occurrence of Bulimina
aculeata characterizes the Stage 2 (last glacial episode) ; this phenomenon has been recognized in other cores (e.g., KT84-14PI; Ujiie, 1990) from this region.
Key words.
slope.

Bathyal benthic foraminifera, oxygen isotope stratigraphy, Ryukyu Trench

Antarctic Bottom Water, North Atlantic
Deep Water and Antarctic Intermediate
Water have been argued by many authors(e.g., Schnitker, 1979; Streeter and Lavery,
1982; Balsam, 1981) based on benthic foraminiferal assemblages contained in sedimentcores. Yasuda et al. (1993) reported the past-----34 kyrs. changes of benthic foraminifera
somewhat analogous to the Atlantic Ocean

Introduction

Bathyal benthic foraminifera are currently
regarded as an important indicator of bottom
water behavior. Particularly in the Atlantic
Ocean, the late Quaternary changes of the'Received March 4, 1994; revised
accepted August 8, 1994

manuscript

497

Xuedong Xu and Hiroshi Ujii€

498

cases in a 784cm long piston core (KT89-18/
P4) from the western Pacific off Shikoku (lat.
32°08.7'N; long. 133°53.6'E; water depth:
2,700 m). Meanwhile, Ujiie et al. (1991)
indicated unique faunal changes in a 416 cm
long core (KT84-14/PI; lat. 23°50.2'N;
long. 124°24. I'E; water depth: 2,488 m)
taken from ca. 300 km northeast of the coresites dealt in this paper, the same area as the
Ryukyu Trench slope region; this corereaches ",-,170 Ka, although KT89-18/P4 andKT84-14/PI are located along the northern
margin of the West Philippine Basin and at asimilar water depth.
Therefore, we would like to obtain more
information on late Quaternary changes ofbathyal benthic foraminiferal fauna prior toinferring the time-space changes of deep water
masses in the northwestern Pacific; suchinformation and oceanographic observation
are scarce in the western Pacific Ocean
compared with the Atlantic.

125°E

Figure 1.

Location and lithology
The Ryukyu Island Arc extends for a distance of about 1,200 km along the northwestern margin of the Pacific Ocean and is separated from the East China Sea shelf by the>2,000 m deep Okinawa Trough. The
southern arc faces the Ryukyu Trench beyond
the rugged topography of the Sakishima
Deep-Sea Terrace, which deepens from",-,2,000 m to ",-,4,000 m southwestward.
A slow sedimentation rate on the terrace is
expected as exemplified by Ujiie et al. (1991).
Two piston cores studied here were collectedfrom the central site (RN87-PC4; lat. 23°50'
N; long. I 24°24'E ; water depth: 2,488 m)
and the outer edge (RN87-PC5; lat. 23°36'
N; long. 124°22'E; water depth: 3,136 m)of the terrace (Figure I).
Core RN87-PC4 is 355 cm long and consists of a rather homogeneous silty clay
sequence, except for an ash layer at 321-324
cm (Figure 2). Bioturbation is scanty. The

127°E

Location map of studied cores (solid stars) and two reference cores (solid circles).

973.

Bathyal benthic foraminiferal changes, southern Ryukyus

top ......... 30 cm is brownish in color suggestingoxidized condition, while the rest of the coreis olive-grayish suggesting reduced condition.
The ash layer was identified as the Ata ash
bed from tephrachronologic procedure(Ahagon et al., 1993).
Core RN87-PC5 is 362 cm long and consists of a relatively homogeneous silty clay,
excluding a laminated portion around 121130 cm (Figure 2). The top 44 cm is an oxidized zone, although its base shows gradual

RN87-PC4

change downward.

Oxygen isotope stratigraphy
More than 30 specimens of Globigerinoides
sacculifer (Brady), a planktonic foraminifera,
are collected from a 2 cm thick sample atevery IO cm interval for stable oxygen andcarbon isotope analyses. Measurement procedures using a Finnigan MAT delta E
mass-spectrometer at Ujiie's Laboratory fol-

G/obigerinoides sacculifero 0 vs PDS (0.<.0)
18

Relative frequencies ofthree suborders

Age Depth
Ka

(cm)

o

10

...

30 100-._.._-_ .._..
"-"-"---"--=-._-..'_.-.--.._..-.,_... -_.
.-_... _._._---"-"-'00_"_,_--"--1.·-·.. .-.':.',:-::-=--_._--'.--_.
-'_00_-

50
200

300
.r:?a.~

110_-__...
--. -_.
..-..--.... _-::"';"!...:.!!-.=..:...

E§3
l=:;;;;I-

Silty clay

~ Textulariina

Lamination or distinct color boundary~Miliolina

Gradually changed boundaryo Rotaliina

Mottles or lumps

499

Tuff

Figure 2. Lithology, planktonic foraminiferal ci 180 stratigraphy, and abundance changes of three
foraminiferal suborders in cores RN87-PC4 and -PC5, respectively. Arrow: the abundance change level
between Gephyrocapsa ericsonii and Emiliania huxleyi; CD~®: oxygen isotope stages; italic figures:control points.

Xuedong Xu and Hiroshi Ujiie

500

RNa7-pe5

Globigerinoides sacculifer

6 ISO vs PDB (%0)

Relative frequencies ofthree suborders

Age Depth

Ka

o

(em)

o

-1

-3

-2

-r"'.-.-';-.';II_.- ..._.

120

--

5.5

.

- --..=..==.:=- - •?

-'-'-"--'
100-"-"-'-'-'-;';'7.-::~' •-'-0._..
'-"-"-"-'... _-_.-.
--"-'--'.. - .. -.. .. _.
-"-"-"-'-'
---.-

_ _.

140

-"--"-- _-..__-"_.-_. .. ..-.. .. .. . ..
."-"-"--".•=.:.-==.:.
--_ .._..-.. •200•..-"-'._00 •. _----.- ..-:::.:::.::.
_---------.
----.160-.. - .. _-..
--.
_.. .__--.
---.---...
-------..
--._---.. - ..
....-"---;.......
- .. _180
.;.
300

.

::-~::-.

:€~~-;.~. :20~=::,::::.

:;=':-=::-.=.

--- _.. --"-"-"-,,-"---.. .. ...

-"-"-00-'.

••

Silty clay

mTextulariina

lamination or distinct color boundary~Miliolina

Gradually changed boundaryo Rotaliina......

Mottles or lumps•

Plnk-plgmented Globigerlnold8s ruber,.~

Figure 2.

low Ahagon et al. (1993). Reproducibilityof this system was better than±0.05 %0 for
0 180 and ±0.03 %0 for 013C, respectively.
In the oxygen isotope fluctuation pattern ofcore RN87-PC4, six control points of Imbrieet al (1984) were recognized and the five
Isotope Stages from I to 5 can be distinguished (Figure 2). At ",-,30 cm below theevent 5.2, the Ata ash bed is intercalated.
This ash bed was dated as ",-,95 Ka by
Ahagon et al. (1993). Slightly above the
Ata ash bed, we observed a level of abundance change between two calcareous nanno-(continued)

plankton species, Gephyrocapsa ericsonii(McIntyre) and Emiliania huxleyi (Lohman).
According to Thierstein et al (1977), G.
ericsonii (= their G. caribbeanica) quickly
increases and E. huxleyi decreases above thelevel within the oxygen isotope stage 5 intheir tropical cores. Core RN87-PC4 also
shows coincident occurrence between the Isotope Stage and this nannoplankton event,although the precise dating of the event leaves
a problem as pointed out by Ujiie et al.
(1991) and Ahagon et al. (1993).
Core RN87-PC5 indicates a quite different

973.

Bathyal benthic foraminiferal changes, southern Ryukyus

pattern in the fluctuation of planktonic 0' 18 0
values from that in RN87-PC4, suggesting thetruncation of the upper portion (Figure 3).
We recognized the last appearance datum ofpink-pigmented Globigerinoides ruber(d' Orbigny) between 50 and 60 cm. This
datum was dated as -----120 Ka by a correlation
with the oxygen isotope stratigraphy (Thomp-

son et al., 1981). Placing an emphasis on
this datum, we concluded that the oxygenisotope fluctuation recognized in core RN87PC5 represents the change from the early 5 to
7 Isotope Stages and then decided the position of four control points; i.e. 5.5, 6.0, 6.4
and 7.0. For RN87-PC5, the abundancechange level between G. ericsonii and E.

AGE (Ka)
40

80

501

160

120

2 0

6.0
100

E

u

300

Ata

RN87-PC4

RN87-PC5

Figure 3. Relationship between core-depth and the ages estimated by isotopic control points and by
the Ata ash bed in cores RN87-PC4 and -PCS.

Xuedong Xu and Hiroshi Ujiie

502

huxleyi is unclear.
Sedimentation rates of two cores are calculated by using these eight time-control points(including Ata ash bed) for RN87-PC4 andfour for RN87-PCS (Figure 3). The sedimentation rate of --....3.60 cmjkyrs. is estimatedfor the portion above the control point 5.0
and --.... 1.50 cmjkyrs. for the portion below 5.0
in RN87-PC4, while the value of ---....6.28 cmj
kyrs. is calculated for the portion above thecontrol point 6.4 and --....2.23 cmjkyrs. for the
portion below 6.4 in RN87-PCS. Based on
Figure 3, therefore, we determined time scalesof both cores and decided that core RN87PC4 represents the past ---.... I IO Ka, while core
RN80-PCS encompasses the period from--....1 IS to ---....210 Ka.

We also noticed that core RN87-PCS lacks
sediments younger than ---.... liS Ka. Such a
missing section cannot be explained by a
failure in sediment recovery during the coring
operation, because the core top sediments areof sufficiently oxidized nature. A plausible
explanation is the presence of an active undercurrent which sweeps sediments off the edgeof the Sakishima Deep-Sea Terrace, the area
where the core was collected. Such anundercurrent was observed beneath the western boundary current in the Atlantic Ocean(e.g., Tucholke and Eittreim, 1974; Schnitker, 1979), but has as yet to be documented in
the Pacific.

®

®

IT] Bolivina decussatafiZ] Epistominella levicula[ ] Globocassidulina bisecta•~ Cassidulina norcrossi

III Astrononion novozealandicum

Bulimina aculeata~Fursenkoina cedrosensis ~cassidulina norvangi

II Epistominella exigua

IBAlabamina ? ruogosa

0 Globocassidulina subglobosa 0 others

Figure 4. Relative frequency changes of II dominant benthic foraminiferal species in cores RN87PC4 and -PCS.

973.

Bathyal benthic foraminiferal changes, southern Ryukyus

Ll
6

6

~

6 'bib'
<D
~

i

51

'"
~
i

g

0
N

..,

SOd-L8NI::I

Figure 5. Down-core changes in the relative abundance of 14 selected benthic foraminiferal taxa incores RN87-PC4 and -PCS.

503

Table 1.

v.

Occurrence chart of "dominant species" in core RN87-PC4.

10- 20- 30- 40- 50- 60- 70- 80- 90- 100:- 110- 120- 130- ~I
92 102 112 122 132
82
52
62
72
32
42
12
22
3
0
1
4
2
4 I
1 Karrerie/la hanzawai (Takayanagi)
6
1
5
3
7
0
2
74 I
19
35
56
52
30
2 Bolivina decussata Brady
28
80
55
65
36
54
40
2
0
0
0
1
3 Bolivina pusil/a Schwager
2 I
0
1
1
2
11
4
2
0
0
0
4
4 Bolivina sp.
1
4 I
0
0
3
7
1
1
1
10 I
8
9
5
20
8
5 Abditodentrix pseudothalmanni (Boltovskoy & Giussani de Khan) 4
12
12
3
6
5
14
3
0
6 Bulimina aculeata d'Orbigny
0
0
2
0
20
1
0
12
23
72
2
0
1
1
1
3
7 Uvigerina proboscidea vadescens Cushman
2
3
0
0
3
5
2
2
5
4
7
5
5
8 Siphouvigerina porrecta (Brady)
3
3
5
1
3
4
1
7
13
4
6
9 Trifarina angulosa (Williamson)
18
4
5
16
6
14
4
6
19
2
5
10 Epistominella exigua (Brady)
15
3
3
4
7
0
0
1
0
1
1
3
18
11 Epistominella levicula Resig
5
12
11
9
16
11
12
10
5
1
0
5
4
1
12 Eponides tenerus (Brady)
2
8
1
2
0
0
3
3
2
1
1
1
13 Eponides lamarkianus (d'Orbigy)
0
2
4
1
2
0
5
3
0
4
0
1
2
14 Eponides tumidulus (Brady)
0
0
2
0
1
1
1
0
1
0
1
2
15 Cibicides cf. refulgens Montfort
4
5
1
0
1
1
3
3
5
1
0
1
0
16 Planulina bradii Tolmachoff & P. wuellerstorfi (Schwager)
0
0
0
1
0
1
0
0
0
4
3
0
3
17 Fursenkoina cedroensis (McCulloch)
1
0
2
1
0
0
2
1
3
4
2
1
2
14
18 Cassidulina cf. neocarinata Thalmann
9
10
9
4
2
6
12
6
6
8
6
7
10
19 Cassidulina norcrossi Cushman
0
6
5
4
6
6
6
4
6
7
8
4
20 Cassidulina norvangi Thalmann
10
11
11
24
10
5
10
12
3
9
4
16
11
21 G/obocassidulina subglobosa (Brady)
19
32
6
33
37
30
26
8
21
20
26
23
32
22 G/obocassidulina bisecta Nomura
13
10
8
17
6
24
5
24
5
15
15
23
19
23 Favocassidulina favus (Brady)
0
0
0
0
0
0
0
0
1
0
0
8
1
24 Evolvocassidulina brevis (Aoki)
0
0
0
0
0
0
0
0
0
0
0
0
0
25 Takayanagia delicata (Cushman)
9
4
6
9
3
8
11
5
7
4
12
5
2
26 Astrononion novozealandicum Cushman & Edwards
16
8
4
11
23
7
9
7
4
15
8
1
7
27 Pullenia sp. B of Ujiie(1990)
4
6
3
4
0
6
9
6
0
0
0
1
4
28 Pulleniella asymmetrica Ujiie
0
2
1
0
0
2
0
0
0
2
1
5
2
29 Gyroidina sp. A of Ujiie(1990)
0
0
1
0
2
4
0
3
0
4
0
1
3
30 Oridorsalis umbonatus (Reuss)
1
4
2
1
2
2
2
4
5
0
1
4
1
31 Alabamina (?) rugosa (Phleger & Parker)
3
2
8
1
9
11
0
1
1
2
1
1
1
32 Melonis sphaeroides Voloshinova
4
3
0
14
0
2
0
0
0
3
6
0
10
33 Melonis barleeanum (Williamson)
0
0
0
0
5
1
0
0
0
0
0
0
1
T Total Specimens
232 350 340 254 398 312 368 270 359 301 305 249 375~

RN87-PC4

-~

~

<1:>

~
~

~
!::l

;::s

I:l...

~

~

-.

.s-'
~~

140- 150- 160- 170- 180- 190- 200- 210- 220- 230- 240- 250- 260- 270 - 280- 290- 300- 310 - 319- 330- 340- 350- 360142 152 162 172 182 192 202 212 222 232 242 252 262 272 282 292 302 312 321 332 342 352 362
15
5
0
0
0
3
1
0
1
2
5
0
3
0
2
1
1
0
1
3
0
4
3
0
53
18
20
18
17
20
26
49
18
30
51
18
7
71
53
34. 31
47
2
18
41
19
18
56
0
0
2
3
2
1
0
0
1
0
0
1
3
1
0
0
0
3
0
0
0
0
0
2
1
3
2
2
1
5
2
6
12
11
12
3
2
2
11
1
10
4
3
5
9
1
0
2
6
6
4
8
5
9
9
12
10
11
9
3
7
3
9
4
0
2
5
8
7
7
10
0
0
0
1
0
0
0
6
6
7
1
1
2
0
0
0
1
1
0
4
0
6
3
2
1
0
1
2
2
0
8
0
2
1
2
1
1
2
4
7
1
3
3
2
7
0 . 0
11
1
3
1
7
3
3
8
5
7
2
3
1
4
7
2
9
1
5
9
3
8
3
6
7
2
7
6
6
3
3
3
4
4
6
2
3
2
1
9
1
1
1
3
9
7
0
1
4
4
3
5
1
1
4
1
26
0
10
3
4
3
6
4
1
0
0
10
5
5
1
0
6
5
16
12
9
5
7
6
6
0
7
12
11
11
11
9
3
10
8
11
19
1
1
2
7
14
4
5
0
1
4
2
0
1
5
1
5
3
2
1
1
3
0
1
12
4
2
0
1
3
0
0
1
1
0
0
0
3
2
0
3
0
0
0
5
1
0
0
0
13
2
2
2
3
0
0
0
1
1
1
3
4
2
4
3
0
1
2
1
2
1
2
1
14
1
1
1
2
3
0
4
3
3
6
4
6
1
1
4
4
2
2
3
3
15
5
2
1
2
8
0
7
3
4
2
4
0
0
3
0
0
3
0
0
1
7
16
0
0
1
2
1
1
3
1
3
8
5
6
0
4
6
0
0
4
2
1
6
3
1
1
4
1
17
5
2
0
2
7
1
7
8
10
0
3
3
5
10
15
3
8
7
17
16
9
8
15
18
7
11
15
10
6
6
15
5
6
9
18
13
11
7
0
4
5
4
1
19 11
5
5
10
4
6
6
5
9
5
11
9
18
4
10
7
11
14
21
18
31
7
6
9
7
11
16
20
3
11
17
5
12
7
38
25
21
29
19
21
27
21
35
36
30
43
33
24
25
22
21
21
24
36
52
23
43
28
13
8
20
15
23
17
15
28
22
16
25
23
14
17
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T 271 325 281 296 244 322 266 257 303 296 268 341 269 331 279 270 264 319 267 281 241 308 267
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Vo

Occurrence chart of "dominant species" in core RNS7-PC5.

o0\

RN87-PC5

3032
0

4042
0

2 Bolivina decussata Brady
3 Bolivina pusilla Schwager

4

0

6

0

1
1
3
1
0
0
2
20
18
8
5
12
1
21
1
0
22
81

2
0

0

4 Bolivina sp.

2
0
4
1
0
0

1
0

1 Karreriella hanzawai (Takayanagi)

10- 20122200

5 Abditodentrix pseudothalmanni (Boltovskoy & Giussani de Khan)
6 Bulimina acu/eata d'Orbigny
7 Uvigerina proboscidea vadescens Cushman
B Siphouvigerina porrecta (Brady)
9 Trifarina angulosa (Williamson)
10 Epistominella exigua (Brady)
11 Epistomine/la levicula Resig
12 Eponides tenerus (Brady)
13 Eponides lamarkianus (d'Orbigy)
14 Eponides tumidulus (Brady)
15 Planulina bradii Tolmachoff & P. wuellerstorfi (Schwager)
16 Fursenkoina cedroensis (McCulloch)
17 Cassidulinacf. neocarinata Thalmann
18 Cassidulina norcrossi Cushman
19 Cassidulina norvangi Thalmann
20 Globocassidulina subglobosa (Brady)
21 G/obocassidulina bisecta Nomura
35
22 Favocassidulina favus (Brady)
7
23 Evolvocassidulina brevis (Aoki)
7
24 Takayanagia delieata (Cushman)
3
25 Astrononion novozealandieum Cushman & Edwards
1
26 Pullenia sp. B of Ujiie(1990)
7
27 Pulleniella asymmetriea Ujiie
2
28 Gyroidina sp. A of Ujiie(1990)
6
29 Oridorsalis umbonatus (Reuss)
6
30 Alabamina (7) rugosa (Phleger & Parker)
21
31 Melonis sphaeroides Voloshinova
2
32 Melonis barleeanum (Williamson)
0
T Total Specimens
349

2
10
13
12
3
4
0
24
0
3
9
30

2
3
3
14
9
7
0
6
4
18
4
2
12
63

29
1

9
3

4
0

1
4

2
·3
0
0
1
3
12
2
2
3
4
2
9
2
0
4
40
21
2
1
0

7072

8082

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11

1

2

2
8

4

2
1

5

9

4

5

4

4

2

5

1
3

2
9
0

1
3
0
0
0

0

2
0

0
0

0

2
0

3
0
3
1
4

7

0
0
5
17
17
5
0
0
2
13
5
6
4
41
24

0
0

8
3

7
4

0

0
0

0

10

17

0
0
0
1
0
1
15
6
1
2
9
1
19
2
1
13
19

0
0
0
0
30
28
12
0
7
0
5
0
1
8
18

15
4

18
8

1

0
1

1

0

0

5

5
4

2
13

9
6

4

7

4

0

1

2
0
3
21
31
13
2
1
2
14
0
1
7
15
20
3
2
3

7

4

1

0
5

3
17
38
13
3
1
0
30
2
1
1
18
34
0
1

2
2
0
0
0
6
20
7
0
0
4
51
3
1
3
11
18
2
0
0

1
1
1
2
15
15
6
5
1
2
47
9
1

17
17

11
0
0

22
22

17
0
1
11
11
4
2
18
44
28

13
1
4
3
0
0
0
2
18
31
8
0
0
6
11
3
10
4
64
41
3
1
3

2

2

2

0

8

9
1

5
5

7
1

0

3

2
6

0

0

2

0

1

11

27
0

33

11

13

0

0

0

0

0

0

1

2
0

213

205

240

225

278

0
261

92

1
0

1
3

1
4

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100- 110- 120- 130102 112 122 132
4
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6062

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29
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229

90-

5052

3
4
20

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4

3

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22
0

15

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7

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0

0

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0

1

0

0

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223

214

221

297

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23
24
25
26
27
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29
30
31
32

T

140- 150- 160- 170- 180- 190- 200- 210- 220- 230- 240- 250- 260- 270- 280- 290- 300- 310- 320- 330- 340- 350- 360
142 152 162 172 182 192 202 212 222 232 242 252 262 272 282 292 302 312 322 332 342 352 362
0
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508

Xuedong Xu and Hiroshi Ujiie
Benthic foraminiferal faunas

The same samples used for isotope analysis
were subjected to benthic foraminiferal analyses. More than 200 (sometimes 300) specimens were picked out at random from fractions coarser than 75,um.
Planktonic ratios (percentage of planktonic
forms versus all foraminiferal tests) are very
high throughout the cores; it ranges from83.5 to 95.5% (94% in average) in core RN87PC4 and from 87.8 to 98.4% (95% in average)
in RN87-PC5. These high ratios suggest thata hemipelagic environment prevailed over theperiod represented by the two cores.
Down-core abundance changes of the three
foraminiferal suborders defined by Loeblichand Tappan (1964; not 1988) indicate thefollowing trends (Figure 2): I) Rotaliinaalways predominates, showing more than 92%
in relative frequency, implying hemipelagic
environment. 2) In core RN87-PC4, a relative proportion of Textulariina seems toincrease during the glacial episodes (Isotope
Stages 2 and 4). 3) In core RN87-PC5, however, Textulariina does not exhibit such atrend but Miliolina is relatively rich in theupper two-thirds of Stage 6.
In Tables I and 2, we document the occurrence of 32 species, whose relative abundances
exceed three percent in anyone of the treatedsamples, with the total number of examined
specimens given at the bottom. Scanningelectron micrographs of the 32 species areshown in Figures 6-10.
Down-core changes in relative abundanceof II species that represent more than 6.8% in

any sample are shown in Figure 4, whereGyroidina sp. A of Ujiie (1990) is excluded
because of the uncertainty of its taxonomic
status. The general patterns of faunalchanges shown in this figure indicate acontrasting difference between two cores. In
core RN87-PC4, faunal changes related to theglaciation and deglaciation are rather indistinct, except for the fact that Bulimina
aculeata (d'Orbigny) predominates exclusively in Stage 2 (last glacial episode). On theother hand, Alabamina ? rugosa (Phleger andParker) is more abundant in Stages 5 and 7(interglacial episodes) in core RN87-PC5.
The blank area in Figure 4, representing the"others" category, donotes combined percentages of those taxa occurring as a minor component of the fauna. Therefore, the area
width depicts the degree of specific diversityof the respective fauna. This "others" category in core RN87-PC4 nearly always
occupies more than 60%, whereas it is lessthan about 40% In RN87-PC5. Thisdifference is considered to reflect the degree of
habitability of the two core sites, with theshallower depth of RN87-PC4 being better
suited for a greater number of species tothrive.
Figure 5 graphically portrays the stratigraphic occurrences of 14 taxa inclusive of II
species shown in Figure 4. All these species
attain more than 3% of the fauna in any given
sample with the exception of a taxon groupconsIstIng of Planulina wuellerstorfi(Schwager) and Planulina bradii Tolmachoff.
Bolivina decussata Brady occurs much moreabundantly throughout RN87-PC4 than in~
Figure 6. Scanning electron micrographs of some representative species. 1: Karreriella hanzawai(Takayanagi) (lateral view), from RN87-PC5, 300-302 cm, X 250. 2, 3: Bolivina decussata Brady. 2:
Broad-test type (lateral view); 3: slender test type (a: lateral, b: apertural views); both from RN87-PC4,
70-72 cm, X 300. 4: Bolivina pusilla Schwager (a: lateral, b: apertural views), from RN87-PC4, 30-32
cm, X 250. 5: Bolivina sp. (lateral view), from RN87-PC4, 310-312 cm, X 300. 6-8: Abditodendrix
pseudothalmanni (Boltovskoy and Guissani de Khan) (lateral views, except for apertural view of 6b). 8:
A variety with not-quadrangled periphery, from RN87-PC4, 90-92 cm; 6 and 7: from RN84-PC4, 280-282
cm; all X 300. 9: Bulimina aClileata d'Orbigny (side view), from RN87-PC4, 40-42 cm, X 250. 10:
Uvigerina proboscidea vadescens Cushman (side view), from RN87-PC4, 350-352 cm. 11: Siphouvigerina
porrecta (Brady) (side view), from RN87-PC4, 310-312 cm, X 300. 12: Trifarina anglilosa (Williamson)(side view), from RN87-PC4, 30-32 cm, X 300.

973.

Bathyal benthic foraminiferal changes, southern Ryukyus

509

Xuedong Xu and Hiroshi Ujiie

510

RN87-PC5. A similar but less distinct trend
can be observed for Abditodendrix pseudothalmanni (Boltovskoy and Guissani de Khan),Takayanagia delicata (Cushman), or
Astrononion novozealandicum Cushman and
Edwards. Contrastingly, Fursenkoina cedrosensis (McCulloch), Epistominella exigua(Brady) and Epistominella levicula Resig are
distinctly richer in RN87-PC5. Evolvocassidulina brevis (Aoki) disappeared at theStage 4/5 boundary, and Alabamina? rugosa
is also somewhat more abundant in RN87PC5. The interglacial Stages 5 and 7 arecharacterized by the increases of A. ? rugosa,
as mentioned above, and of Pulleniella asymmetrica Ujiie. The former species slightly
increases in the postglacial period (Stage I).
Discussion
Planktonic foraminiferal 0 180 stratigraphy
revealed that core RN87-PC4 reaches"" 110
Ka (middle Stage 5), whereas core RN87-PC5
represents the period from"" 115 Ka to ",,210
Ka (middle Stage 5 to upper Stage 7). By
taking the two cores as a composite section,
therefore, a continuous stratigraphic occurrence of benthic foraminifera for the past",,210 kyrs. can be monitored in the trenchslope region off Ishigaki Island. Before discussing of this, however, we must emphasize
the 648 m difference in water depth between
the cores (RN87-PC4: 2,488 m, RN87-PC5:
3,136 m), even though the coring sites are
only 25 km apart.
Different habitats related to water depth
can be expected for Bolivina decussata, Takayanagia delicata and Astrononion novo-

zealandicum, all of which are clearly more
predominant in the shallower core, RN87PC4, than in RN87-PC5, as well as for Fursenkoina cedrosensis, Epistominella exigua,
Epistominella levicula and Evolvocassidulina
brevis, all of which are characteristicallyricher in RN87-PC5, as explained above.
Nevertheless, abundant occurrences of both
E. exigua and A. novozealandicum in Stage 6
were observed in core KT84-14/PI (lat. 23°50.
2'N; long. 124°24. I'E; water depth, 2,488m) raised from the margin of the Sakishima
Deep-Sea Terrace about 275 km eastnortheast of RN87-PC4 (Ujiie et al., 1991).
This 416 cm long core covers that past ",,170
kyrs. Other dominant species, however,show large discrepancies in their stratigraphic
occurrences, probably because of different test
sizes treated. For core KT84-l4/PI, fractions coarser than 105 Jim were treated, andfor both RN87-PC4 and -PC5 fractions coarser than 75 Jim.
More significant differences are recognized
between our cores and a core KT89-18/p4
collected from seas off the coast of Shikoku,
Southwest Japan (lat. 32°8.7'N; long.
133°53.6'E; water-depth, 2,700 m) (Yasuda
et al., 1993). In a preliminary report, Yasuda
et al. showed down-core changes in theoccurrence of major benthic foraminiferal
components that are somewhat analogous to
the North Atlantic studies reported byStreeter an Lavery (1982) who treated the> 149 Jilm fraction, Schnitker (1979) who
treated the > 125 Jim fraction, and Balsam(1981) who did not indicate what fraction
was used. The purpose of these studies wasto estimate bottom water-mass changes during~
Figure 7. 1,2: Epstominella exigua (Bardy). I: Adult (a: spiral side, b: apertural edge views) ;2: young form (spiral side view); both from RN83-PCS, 230-232 em, X 300. 3: Epistominella levicula
Resig (a: spiral side, b: apertural edge views), from RN87-PCS, 230-232 em, X 300. 4: Eponides tenerus(Bardy) (spiral side view), from RN87-PCS, 210-212 em, X 300. 5: Eponides lamarckianus (d'Orbigny)(spiral view), from RN87-PC4, 160-162 em, X 300. 6: Cibicides ef. C. relulgens Montfort, Juvenile form
(a: spiral side, b: umbilical side, e: apertural edge views), from RN87-PC4, 190-192 em, X 400. 7,8:
Planulina bradii Tolmaehoff (a: spiral side, b: apertural edge views). 7: Adult from RN87-PCS, 160-162
em, 8: Juvenile form from RN87-PCS, 140-142 em; both X 200. 9,10: Planulina wuellerstorfi (Schwager)(a: spiral, b: apertural edge views). 9: Adult from RN87-PCS, 290-292 em, X 100; 10: young form from
RN87-PCS, 250-252 em, X 150.

973.

Bathyal benthic foraminiferal changes, southern Ry uky us

5 11

512

Xuedong Xu and Hiroshi Ujiie

the period from the last glacial to Recent
based on analyses of benthic foraminiferal
assemblages. In particular, Yasuda et al.
(1993) emphasized that Uvigerina peregrina
disappeared around '" 10 Ka after its abundant occurrence in the last glacial episode,which is marked by similar occurrences ofMelonis barleeanum and Melonis sphaeroides. They supposed that the Circumpolar
Deep Water or Antarctic Intermediate Water
characterized by the three species was displaced by the North Atlantic Deep Water(NADW) after the last glacial episode as wellas in the North Atlantic Ocean. In core
KT84-14/Pl from the Ryukyu Trench slope
region (Ujiie et al., 1991), however, no similar mode of species occurrence can be recognized, even though the test size treated issimilar to that of Yasuda et al. (1993).
Besides, no oceanographer recognized thewater corresponding to the NADW in thenorthern Pacific.
For further comparative study of benthic
foraminifera from core to core, we would liketo point out the need of the same or similarsized fractions. Particulary, test sizes
between 75 J.lm and 103",148 J.lm should be
examined because a considerable number ofbenthic species occur as small-size adults.
For examples, such minute- but dominant
species as Bolivina decussata, Epistominella
levicula, and Fursenkoina cedrosensis, allcharacteristic of cores RN87-PC4 and -PC5,
were hardly observed in the fraction coarser
than 103 J.lm of core KT84-14/Pl as dominant taxa.

The next problem concerns the taxonomy,
which seems to differ from author to author.
Every foraminiferalogist has his or her own
opinions regarding the taxonomic status ofmany species and this is to be expected.
However, every author should strive to illustrate (and if possible, describe) major species,at least those of critical importance to thesubject of the paper, in order to give otherauthors every convenience for comparisons.
Judging from a drawing of umbilical side,
Osangularia umbonifera (Cushman) of
Schnitker (1979) (=? Nuttallides umbonifera
of Yasuda et al., 1993) may be identical to
Alabamina? rugosa in our study. As
pointed out by Ujiie (1990), A. ? rugosa haserroneously been reported under various
specific names, sometimes under the genus
Nuttallides. Recently, Loeblich and Tappan(1994) assigned this species as Nuttallides
rugosus without any notice on the genericheterogeneity of its type species, Eponides
truempyi Nuttal, 1930. Ujiie (1990) also
distinguished Oridorsalis umbonatus (Reuss)and Eponides tenerus (Brady) by a detailed
anatomic analysis, though some authors madeisotope measurements by treating the two
species as a single taxon. In our study, we
found that Planulina bradii may have beengrouped with Planulina wuellerstorfi in many
previous works. A.? rugosa, O. umbonatus
and P. wuellerstorfi have been recognized asimportant indices of bottom water (e.g.,Schnitker, 1979; Streeter and Lavery, 1982).
The last problem to be proposed here is
how to accumulate information regarding the~ Figure 8. 1: Fursenkoina cedrosensis (McCulloch) (lateral view), from RN87-PC4, 90-92 cm, X 300.
2,3: Cassidulina cf. C. neocarinata Thalmann (apertural lateral views). 2: Young form, X 250; 3:
adult, X 200; both from RN87-PC4, 190-192 cm. 4: Cassidulina norcrossi Cushman (apertural lateralview), from RN87-PC5, 130-132 cm , X 300. 5: Cassidulina norvangi Thalmann (a: apertural lateral, b :apertural edge views), from RN87-PC4, 270-272 cm, X 400. 6: Globocassidulina subglobosa (Brady) (apertural lateral view), from RN87-PC4, 250-252 cm, X 300. 7,8: Takayanagia delicata (Cushman) (a:apertural lateral, b: apertural edge views). 7: Specimen with grooves radiating from the apertural face likein Takayanagia quasisulcata (Belford) (= Cassidulina quasisu/cata Belford, 1966), although the othercharacters are identical to T. delicata; 8: normal type, both from RN87-PC4, 270-272 cm, X 400. 9:
Globocassidulina bisecta Nomura (apertural lateral view), from RN87-PC4, 360-362 cm, X 400. 10:
Favocassidulina favus (Brady) (lateral view opposite to apertural side), from RN87-PC5, 280-282 cm, X 100.

973.

Bathyal benthic foraminiferal changes. southern Ryukyus

5 13

Xuedong Xu and Hiroshi Ujiie

514

distribution of Recent benthic foraminifera in
the Northwest Pacific Ocean, where suchinformation is scanty. Inoue (1989)
compiled the benthic foraminiferal distribution in seas adjacent to Japan using numerous
sediment dredgings along with a few piston
cores. However, dredged samples and the
top of piston cores do not represent realsurface sediments in many cases, because theformer are frequently contaminated witholder sediments and the latter lose the top few
em in the core pushing-out process owing totheir soupy nature. Therefore, the assemblages contained in those samples can't bestrictly correlated to oceanographic observation on bottom waters. Instead, we are collecting many top samples of pilot corers andof multiple corers in order to clarify real
Recent distribution of benthic foraminifera
around the Ryukyu Island Arc region. At
present, we should document in detail downcore changes of benthic foraminiferal assemblages as much as possible, before we speculate on the relationship between the assemblages and bottom water conditions so far as
the Northwest Pacific Ocean cases are concerned.

Conclusions
A planktonic foraminiferal oxygen isotope
stratigraphy provides a kind of analog timescale for two piston cores, RN87-PC4 and-PC5. The former was collected from
2,488 m in water depth in the middle part of
the Sakishima Deep-Sea Terrace south ofIshigaki Island, Okinawa, and the latter froma 3,136 m-depth and the terrace edge. The
time scale was substantiated by recognizing atephrachronology based on the Ata ash bed
and by two micropaleontologic events, namely the abundance change between two calcareous nannoplankton species, Gephyrocapsa
ericsonii and Emiliania huxleyi, and the lastappearance datum of pink-pigmented
Globigerinoides ruber.
Core RN87-PC4 contains an oceanographic record spanning the past ........ 110 kyrs. and
RN87-PC5 covers the period from ........ 115 Ka
to ........210 ka. The missing sequence younger
than ........ I 15 Ka in the latter core may beascribed to scouring by an unknown bottom
current along the outer edge of the Sakishima
Deep-Sea Terrace.
Based on the time scale thus established, we
showed down-core changes in a relative abundance of 32 dominant benthic foraminiferal
taxa. Bulimina aculeata predominates characteristically in the last glacial episode (Isotope Stage 2). Epistominella exigua becomesdominant in the period older than Stage 5,
while Astrononion novozealandicum increases
its abundance upward after the middle ofStage 5. These trends were recognized incore KT84-14/Pl that was raised from thesame Sakishima Deep-Sea Terrace, some 275
km north-northeast of RN87-PC4. We also
observed biased occurrences in RN87-PC4 of
Bolivina decussata, Abditodendrix pseudothalmanni and Takayanagia, in contrast to
Fursenkoina cedrosensis and Epistominella
levicula which are more abundant in RN87PC5. At present, however, we are uncertain
as to whether these biased modes of occurrence were due to different geologic times or
to different water-depths; there is a 648 m
depth difference between the two cores.
Additionally, we pointed out that~
Figure 9. 1,2: Evolvocassidulina brevis (Aoki) (lateral views except for I b, apertural view), bothfrom RN87-PC5, 270-272 cm, X 400. 3: Astrononion novozealandicum Cushman and Edwards (a: lateral,b: apertural edge views), from RN87-PC5, 60-62 cm, 'X 300. 4,5: Pullenia sp. of Ujiie (1990). 4 :involute type (a: lateral, b: apertural edge views), from RN87-PC4, 250-252 cm; 5: lateral view of weakly
evolute type, from RN87-PC5, 130-132 cm; both X 300. 6-8. Pulleniella aymmetrica Ujiie (b: aperturaledge view). 6a, 8a: incompletely coiled side views of adult and juvenile form, respectively; 7a: completely
coiled side view of young specimen; all from RN87-PC5, 350-352 cm, X 250. 9: Gyroidina sp. A of Ujiie(1990) (a: spiral side, b: apertural edge views), from RN87-PC5, 50-52 cm, X 300.

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Bathyal benthic foraminiferal changes, southern Ryukyus

515

Xuedong Xu and Hiroshi Ujii€

516

Alabamina? rugosa and, though subordinately, Pulleniella asymmetrica predominated Stages 5 and 7 assemblages.
In this paper, we have refrained from discussing the relationship between the mode ofoccurrence of benthic foraminifera andoceanographic conditions of bottom waters,
since our knowledge on the distribution of
Recent benthic foraminifera in the Northwest
Pacific is insufficient.
Acknowledgments
We are indebted to Captain Uero Yadaand crew of the R/V Nagasaki-maru for theircooperation. Tomonori Ono, University of
the Ryukyus, and Tohru Nakasone, Kawasaki Chishitsu Co., and Naokazu Ahagon,
University of Tokyo, assisted us in the shipboard and laboratory work. Yuichiro Tanaka, Geological Survey of Japan, kindly provided us with the information on calcareous
nannoplankton stratigraphy. The first draft
was reviewed by Motoyoshi Oda, Kumamoto
University. Particularly, we are indebted to
Tsunemasa Saito, Tohoku University, for his
thorough and critical review of the manuscript. Anonymous reviewers gave us usefuladvice on the manuscript. This work was
supported in part by Grand-in-Aids from the
Ministry of Education, Science and Cultureof Japan given to H.U. (02640603) and funds
from the Nippon Life Insurance Foundation
given to H.U.

Faunal references
The following list of taxonomic references
concerns 31 species listed as "dominant
species" in Tables I and 2. Publication

names are not given when they are cited in thereferences section of this paper. Asterisk
denotes those species for which Ujiie (1990)
gave a description, cited more detailed taxonomic references, or both.
Karreriella hanzawai (Takayanagi)* (Figure 6-1)
Tosaia hanzawai Takayanagi, 1953, Short
Papers, Inst. Geol. Paleont. Sendai, no. 5, p. 30,
pI. 4, figs. 7a, b.
Karreriella hanzawai (Takayanagi), Ujiie, 1990,
p. 13, pI. 2, figs. 6a-8b).
Bolivina decussata Brady (Figure 6-2, 3)
Bolivina decussata Brady, 1881, Quart. Jour.
Micro. Sci., New Ser., vol. 21, p. 28 ;-Brady,
1884, Rep. Voy. Challenger, Zoology, vol. 9, p.
423, pI. 53, figs. 12, 13.
Bolivina pusilla Schwager* (Figure 6-4)
Bolivina pusilla Schwager, 1866, Novara-Exped.,
Geol. Theil, vol. 2, p.254, pI. 7. fig. IOJ.
Abditodendrix pseudothalmanni (Boltovskoy andGuissani de Khan)* (Figure 6-6-8)
Bolivina pseudothalmanni Boltovskoy and Guissani de Khan, 1981 (fide Loeblich and Tappan,
1988, p. 503, pI. 554, figs. 1-5).
Abditodendrix pseudothalmanni (Boltovskoy
and Guissani de Khan), Ujiie, 1990, p. 29, pI. 12,
figs. 2a, b.
.
Bulimina aculeata d'Orbigny" (Figure 6-9)
Bulimina aculeata d'Orbigny, 1826, Annales Sci.
Nat., vol. 7, p.269, no. 7.
Uvigerina proboscidea vadescens Cushman" (Figure
6-10
Uvigerina proboscidea Schwager, var. vadescens
Cushman, 1933, u.S. Nat. Mus. Bull., no. 104, p.
85, pI. 8, figs. 14, 15.
Siphouvigerina porrecta (Brady)' (Figure 6-11)
Uvigerina porrecta Brady, 1879, Quart. Jour.
Micro. Sci., New ser., vol. 19, p. 31 ;-Brady,
1884, Rep. Voy. Challenger. Zoology, vol. 9, p.
577, pI. 74, figs. 21-23.
Trifarina angulosa (Williamson) (Figure 6-12)
Uvigerina angulosa Williamson, 1858, On the
Recent Foraminifera of Great Britain, Ray Society, London, p. 67, fig. 140.
Trifarina angulosa (Williamson), Loeblich andTappan, 1964, p. C571, figs. 450-\a-3.

~ Figure 10. 1,2: Oridorsalis umbonatus (Reuss).
\: Adult (a: spiral side, b: umbilical side, c:
apertural edge views), X 150; 2: juvenile form already provided with a supplementary aperture (spiral sideview), X 300; both from RN87-PC5, 10-12 cm. 3: Alabamina? rugosa (Phleger and Parker) (a: spiralside, b: umbilical side views), from RN87-PC5, 50-52 cm, X 300. 4,5: Melonis sphaeroides Voloshinova.
4: adult (a: lateral, b: apertural edge views), X 200; 5: lateral view of juvenile form, X 400; both from
RN87-PC5, 50-52 cm. 6: Melonis barleeanum (Williamson) (lateral view), from RN87-PC5, 290-292
cm, X 200. 7: £ponides tumidulus (Brady) (a: spiral, b: umbilical side views), from RN87-PC5, 10-12
cm, X 300.

973.

Bathy al benthic foraminiferal changes, southern Ry uky us

517

Xuedong Xu and Hiroshi Ujiie

518

Epistominella exigua (Brady)· (Figure 7-1, 2)
Pulvinulina exigua Brady, 1884, Rep. Voy. Challenger. Zoology, vol. 9, p.696, pI. 103, figs. 13a14c.

Epistominella exigua (Brady), Parker, 1954, Bull.
Mus. Comparative Zoo I., vol. III, no. 10, p. 533,
pI. 10, figs. 22, 23.
Epistominella levicula Resig· (Figure 7-3)
Epistominella levicula Resig, 1958, Micropaleontology., vol. 4, no. 3, p.304, text-fig. 16(see Ujiie, Ichikura and Kurihara, 1983, for further references).
Eponides tenerus (Brady)· (Figure 7-4)
Truncatulina tenera Brady, 1884, Rep. Voy.
Challenger, Zoology, vol. 9, p. 665, pI. 95, figs.
I la-c.
Eponides tenerus (Brady), Cushman, 1927, Bull.
Scripps Inst. Oceanogr., Tech. ser., vol. I, p. 163,
pI. 5, figs. 6, 7 ;-Ujiie, 1990, p.34, pI. 16, figs.
5a-6; text-fig. I).
Eponides lamarckianus (d'Orbigny)· (Figure 7-5)
Rotalina lamarckiana d'Orbigny, 1839, inBarker-Webb, P., and Berthelot, S., Histoire
naturelle des iles Canaries, Beth une, Paris, vol. 2,
p. 131, pI. 2, figs. 13-15.
Eponides tumidulus (Brady)· (Figure 10-7)
Truncatulina tumidulus Brady, 1884, Rep. Voy.
Challenger, Zoology, vol. 9, p.666, pI. 95, figs.
8a-c.
Eponides tumidulus (Brady), Cushman, 1931,
U.S. Nat. Mus. Bull., no. 104, p.55, pI. II, figs.
6a, b.
Planulina bradii Tolmachoff (Figure 7-7, 8)
Truncatulina wuellerstorfi (Schwager), Brady,
1884, Rep. Voy. Challenger. Zoology, vol. 9, pI.
93, figs. 8a-c, not figs. 9a-c (not Anomalina wuellerstorfi Schwager, 1866).
Planulina bradii Tolmachoff, 1984, Ann. Carnegie Mus., p.333.
Planulina wuellerstorfi (Schwager)· (Figure 7-9, 10)
Anomalina wuellerstorfi Schwager, 1866, Novara-Exped., Geol. Theil, vol. 2, p.258, pI. 7, fig.
107.
Planulina wuellerstorfi (Schwager), Cushman,
1929, Contr. Cushman Lab. Foram. Res., vol. 5,
p. 102, pI. 15, figs. 1,2.
Fursenkoina cedrosensis (McCulloch) (Figure 8-1)
Neobuliminoides cedrosensis McCulloch, 1977,
Qualitative Observations on Recent Foraminiferal Tests with Emphasis on the Eastern Pacific,
Univ. Southern Calif., L.A., p.247, pI. 104, figs.
27,28; pI. 578, figs. 24-25.
Cassidulina cf. Cassidulina neocarinata Thalmann·(Figure 8-2, 3)
Cassidulina cf. neocarinata Thalmann, Ujiie,
1990, p. 38, pI. 18, figs. 6a, b.
Cassidulina norcrossi Cushman (Figure 8-4)

Cassidulina norcrossi Cushman, 1933, Smithsonian Misc. Coil., vol. 89, no. 9, p.7, pI. 2, figs.
7a-c.
Cassidulina norvangi Thalmann· (Figure 8-5)
Cassidulina norvangi Thalmann, 1950 (inPhleger, 1952, Contr. Cushman Found. Foram.
Res., vol. 3, no. 2, p. 83.
Globocassidulina subglobosa (Brady)· (Figure 8-6)
Cassidulina subglobosa Brady, 1881, Quart. Jour.
Micro. Sci., New ser., vol. 21, p. 60 ;-Brady,
1884, Rep. Voy. Challenger, Zoology, vol. 9, p.
430, pI. 54, figs. 17a-c.
Globocassidulina subglobosa (Brady), Belford,
1966, Bur. Mineral Res. Geol. Geophysics, Australia, Bull., no. 79, p. 149, pI. 25, figs. 11-16.
Globocassidulina bisecta Nomura (Figure 8-9)
Globocassidulina bisecta Nomura, 1983, Sci. Rep.
Tohoku Univ., 2nd ser., vol. 53, no. I, p.73.
Favocassidulina favus (Brady)· (Figure 8-10)
Pulvinulina favus Brady, 1877, Geol. Magazine,
New ser., vol. 4, p. 535; Brady, 1884, Rep. Voy.
Challenger, Zoology, vol. 9, p. 701, pI. 104, figs.
12a-16.
Favocassidulina favus (Brady), Loeblich andTappan, 1957, U.S. Nat. Mus. Bull., vol. 215, p.
230, pI. 73, figs. 7-11.
Evolvocassidulina brevis (Aoki) (Figure 9-1,2)"Cassidulina" brevis Aoki, 1968, Trans. Proc.
Palaeont. Soc. Japan, N.S., no. 70, p. 261, pI. 27,
fig. 4.
Evolvocassidulina brevis (Aoki), Nomura, 1983,
Sci. Rep. Tohoku Univ., 2nd ser., vol. 54, no. I,
p. 49, pI. 4, figs. 4a-7; pI. 20, fig. II ; pI. 21, figs.
1-5; text-figs. 41-43.
Takayanagia delicata (Cushman) (Figure 8-7, 8)
Cassidulina delicata Cushman, 1927, Bull.
Scripps Inst. Oceanogr., Tech. ser., vol. I, no. 10,
p. 168, pI. 6, fig. 5.
Takayanagia delicata (Cushman), Nomura,
1983, Sci. Rep. Tohoku Univ., 2nd ser., vol. 53, p.
53, pI. I, figs. 3; pI. 7, figs. 1-5.
Astrononion novozealandicum Cushman and
Edwards· (Figure 9-3)
Astrononion novozealandicum Cushman and
Edwards 1937, Cushman Lab. Foram. Res., vol.
13, pt. I, p. 35, pI. 3, figs. 18a, b.
Pullenia sp. B· (Figure 9-4,5)
Pullenia sp. B, Ujiie, 1990, p. 44, pI. 22, figs. 12a13b; pI. 24, figs. lOa, b.
Pulleniella asymmetrica Ujiie· (Figure 9-6~8)
Pulleniella asymmetrica Ujiie, 1990, p.45, pI. 23,
figs.3a-b.
Gyroidina sp. A (Figure 9-9)
Gyroidina sp. A, Ujiie, 1990, p.47, pI. 27, figs.
2a-c.
Oridorsalis umbonatus (Reuss)· (Figure 10-1,2)Rotatina umbonata Reuss, 1851 (fide Ellis and973.

Bathyal benthic foraminiferal changes, southern Ryukyus

Messina, 1940 et seq.).
Oridorsalis umbonatus (Reuss), Parker, 1964,
Jour. Paleont., vol. 38, no. 4, p. 626, pI. 99, figs.
4-6 ;- Ujiie, 1990, p. 48, pI. 28, figs. 1-6; text-fig.
4.
Alabamina ? rugosa (Phleger and Parker)" (Figure
10-3)
Pseudoparrella ? rugosa Phleger and Parker,
1951, Geol. Soc. America, Mem., no. 46, pt. 2, p.
28, pI. 15, figs. 8a -9b.
Alabamina ? rugosa (Phleger and Parker), Ujiie,
1990, p.49, pI. 29, figs. la-2c.
Nuttallides rugosa (Phleger and Parker), Loeblich and Tappan, 1994, Cushman Found. Foram.
Res., Spec. Pub., no. 3 I, p. 156, pI. 350, figs. I 113.
Melonis sphaeroides Voloshinova" (Figure 10-4,5)Melonis sphaeroides Voloshinova, 1958, Mikrofauna SSSR, Sbornik 9, Trudy, no. 115, p.
153, pI. 3, figs. 8a, b.
Melonis barleeanum (Williamson)" (Figure 10-6)
Nonionina barleeanum Williamson, 1858, On the
Recent Foraminifera of Great Britain, Ray, Soc.,
London, p. 31, pI. 3, figs. 68, 69.
Melonis barleeanum (Williamson), Pflum andFrerichs, 1976, Cushman Found. Foram. Res.,
Spec. Pub., no. 14, pI. 7, figs. 5, 6.

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520

Sakishima 7t~, Ishigaki :otl[, Miyako -gr!!, Kerama ~.JltFI"I'.
~$:210,OOO~rl"l,':mt~*;*#:ij'lilHL$~~~1t: ml)ftJ;j{~· :O±l[~m:n5~1::'.A 1-::..::J 71.1' ~O)'~~: :O:lj[~m1f0)ll~#iJ~I;:~U7t~~th.PjZt!!iHL.t0)*~ 2,488 m t ~~*l<$O)*~ 3,136 m iJ'l? l:' A 1'- / . ::I 7 RN87-PC4 t RN87-PC5 ~f*l& IA.:. W-1lft'/j::f:f1L$

Globigerinoides sacculifer O)JN:~ m ~,t.:~~~f:iL'Pfdff-t1R7Ht, 1fIiJ~ j(ilIEJ(~O)1f:f-t~ =-::>
1'- 1;:X'<j L.l '{, WijJ~lY-Jl'ti; t), RN87-PC4 1;:I:~~~f:iL1*A T - ~ CD
iJ'l? @ l', RN87-PC5 1;:I:@iJ'l? ® L'~7J/f- L.lv, .:o.~~H)3l?iJ'l;: L.t.:. RN87PC5 IU,H'l @ J:$j:JJ:iJ~Xltl~'.:o ;: t 1;:1:, 7t~~#iJ:>jZmlIii~*l<$I;:ta? l*e9~ t~t~H;: Western Boundary Undercurrent iJ~fftE L.l~'.:o i:lJijgtt ~:iF~T.:o '{, o)l'ti;.:o. ;:? L.lm.1? nt.:~* 210,000 1f:FI"I,O)aij,*JU I;: -::>~, l, ®1:.:f:f1L!R0)1I~m (~'-rniJ'O)-lj­/7' )vl' 3% ~~;t .:om) 32 O)ggl±lj!:~ft~*.li)t.:. !j;~fI;:iJ~WijJT~ ~.~ 1;:1:, Alabamina?
rugosa t itJi(i>]iJ~ J: t) l'IJi~l'l;l:t;~~'iJ~ Pulleniella asymmetrica O)ggl±lj!:iJ~, ~~*tlNtO)~1t
1;:X'<jJ;C; L.l~'.:o ;: t t, Bulimina aculeata iJ~l'&~7l<M (~~~f:iL1*A T - ~ ®) 1;:¥.if,&i19~ggI±lT.:o;:tl'ti;.:o.
• ~.·re.
0)~r!!1:.~~rF1 r'j:r. /

*

*

*

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 175, pp. 521-552,8 Figs., September 30, 1994

974. PLANKTONIC FORAMINIFERAL BIOSTRATIGRAPHYOF UPPER PALEOCENE TO MIDDLE EOCENESEQUENCES IN THE EASTERN
DESERT AREA, EGYPT*HIROSHI NISHI
Institute of Geoenvironmental Science, Faculty of Science,
Tohoku University, Sendai, 980 Japan

ASHRAF M.T. ELEW A
Geology Department, Faculty of Science,
El Minia University, Egypt
andKUNIHIRO ISHIZAKI
Institute of Geoenvironmental Science, Faculty of Science,
Tohoku University, Sendai, 980 Japan

Abstract. The studied sections are located in the Eastern Desert area, along the El
Sheikh Fadl road running from Ras Gharib on the west bank of the Gulf of Suez to
El-Sheikh Fadl village on the east side of the Nile River. Rocks exposed in this area
comprise five lithological units, the Esna (shale), Thebes (limestone and chert), Maghagha(marl and limestone), Qarara (shale and sandstone) and El Fashn (limestone) Formations,and can be divided into the following five planktonic foraminiferal biozones; the Planorotalites pseudomenardii Zone, Acarinina aspensis Zone, Globigerinatheka subconglobata
Zone, Morozovella lehneri Zone and Truncorotaloides rohri Zone in ascending order.
Although some zonal marker species have not been found in the investigated area, thesezones are considered to correspond, respectively, to Zone P4, Zones P9-1O, lower Zone Pl1,
upper Zone Pll, Zones P12-14 of the standard zonation established in low latitude areas.
Therefore, the Esna Formation is assigned to the late Paleocene, the Thebes Formation to
the late Paleocene to latest early Eocene, and the Maghagha and Qarara Formations to the
middle Eocene. The limestone-marl Maghagha Formation was deposited in the west,
simultaneously with the sandstone-shale Qarara Formation in the east.
Key words.
Desert, Egypt.

Planktonic foraminifera, biostratigraphy, Paleocene, Eocene, Eastern

the following four major provinces from west
to east; the Western Desert, the Nile Valley
and the Delta, the Eastern Desert, and theSinai Peninsula. Biostratigraphical investigations of planktonic foraminifera have been
made mostly in the Nile Valley (e.g. Said,

Introduction

Egypt is divided geomorphologically into
"Received March 28,
accepted July 5, 1994

1994; revisedmanuscript

521

522

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

L-__-L__-L~,-~~__I~~~2~8~kmr_----~----._------~~~L---~~~~

32°

31°

280

33°E

Figure 1. Map showing locations of the sections measured along the EI Sheikh Fadl-Ras Gharib
stretch, the Eastern Desert. I. Gebel EI Sheikh Fadl section, 2. Gebel EI Mohasham section, 3.
section at km 8, 4. section A at km 10, 5. section Bat km 10, 6. Gebel EI Mereir section at km 18,
7. Gebel EI Mereir section at km 40, 8. Gebel EI Mereir section at km 68, 9. Gebel El Mereir section
at km 92, 10. section at km 127, II. section at km 140. km refers to the distance (km) from the village
of EI Sh~ikh Fad\.

1960; Said and Sabby, 1961 ; Abdel-Kireem,
1985; Haggag, 1989a, 1989b), Sinai (e.g. Saidand Kenawy, 1956; Haggag and Luterbacher, 1991 ; Shahin, 1992), and in small oases
in the Western Desert such as the Farafra(Said and Kerdany, 1961) and the Kharga(Nakkady, 1959; Abdel-Kireem et al., 1985).
The Eastern Desert was studied with a biostratigraphical emphasis on the Esna Formation (Shales) (e.g. Nakkady, 1950), while a
few workers dealt with middle Eocene planktonic foraminifera in this area (Khalifa and
EI-Sayed, 1984). Along the El Sheikh Fadlroad traversing the Eastern Egyptian Desert,
Paleogene sequences are distributed. Thisroad extends for a distance of approximately
245 km from Ras Gharib on the western coastof the Gulf of Suez to EI-Sheikh Fadl village
on the eastern bank of the Nile River near
Beni Mazar. Older, pre-Tertiary rocks are
exposed widely in the eastern region close to
the Gulf of Suez. The Paleogene sections
occupy the western region. A total of 11
sections were measured in this area (FigureI). We were successful in obtaining abun-dant foraminifer and ostracode specimensfrom these sections, thus enabling the establishment of biostratigraphic divisions basedon these microfossils for the late Paleocene to
middle Eocene interval. This paper focuses
on a planktonic foraminiferal biostratigraphyof the Eastern Egyptian Desert, giving
descriptions of the recognized zones anddiscussing a correlation with other zones andtheir geological ages. Biostratigraphical andpaleontological conclusions for the ostracodes were summarized by Elewa and Ishizaki (1994).
Lithostratigraphy

The Paleogene rocks exposed along the EI
Sheikh Fadl road can be divided lithologically into the follwing rock units in ascendingorder:The Esna Formation
The Esna Formation was originally described by BeadneII (1905) as the Esna Shaleconsisting of think green and gray shale
1.

S~.

ThebesEsna..,
0n>....,

1:);:'.0"2.

•• rnDBllffill~l[Il~f}~a~::1~ "',:. :;:- ~~cnocnoI:l :0:::...

g Cl

I>'

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n'=:

3;:l
:;. ~
_'1>'

g.~~
~ ::::-:.
~:;; ..

;;1~
.
0..

..... I:l~. ::t:.§

.. :.

~

:. ;:;- ~V) ~ •.

§..~(j<:l-;:,;:,.
I:) _"..... ;::s ••S' I:lI:l •• (j•. ::t: ~
~;:,~

~~~
....
~

::t:<:l~I:l~§ ~.~.

8 ~ ..

...
~I:ll:lti ;:,:::!. Cl;:,

I:) • • •~~ ..

"'. 52•...
g..
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~

-l=:
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:=.

;:l0tl
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I>'

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oq'::r
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c:~

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n> ;:l.., ntiln>o....,....,
0no -::r_n>

c: tTl3 til;:l ;:l

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:=. go n>;:l tiltil•

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n> ;:l;:l 0..

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;:l ;:l

N:O::: s·:::!. I:l~r,,~:o:::~

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~

s:. •.

-.Oq;:, '1>

til

'1>

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~

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~ A. conveta:.........., A. mclennnai~ A. praeangulata.........., M. velascoensis aeula
M. angulata~ M. ace/usa ace/usa............, Pl. albeari~ Pl. pseutlomenardii

•
•

,.

,

•

•
•
•
,
,
~
~

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'
:
••
::
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~,

+-*--'~Pl.pustl/Qpusll/a............, S. triangularis~ S. trilocl.llinoides............ S. velascoensis
A. eSllaellsis........ Ch. c,!nita.

t

H~CIt.mldwa)'ensls

H

:

tf::

'
~
,
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,

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~': Gka. mexicana kugleri:+:, A. broedermannii' . ,,:. 'Hila. cr. bolivariana: , , :::'I
I~ S. eocaella~ Tds. rohri
.
I

•

I

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.:

• Glen. mexicana mexicQnQ::: : :~
A. penlac~m~ra:a ~~merata,

H. mexicQna

.

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i

: ::::. t'": ; ;! #' :: '. S. Jrontosa Jrontosa
S. inaequispiraA. bul/brookii~

Mlla.senni+S. Jrontosa boweri• Trt. cerroazulensis possagnoensis

i t ~ g~!:::~umbiana~: A. densa
N: s. hagni~: Tds. pseudodubia

-;;1

:=.

+:;

tIl~
I>' ::r
3 -.
;:l ~

r;j"~
n> _.
.., 0
Y' ;:l+!'!'I. . .... .

oq'r;j"c: _ .
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~

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A. aspensis

w;

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:
: ",,:, ~:: :::\,01, , Gkn. subcongloba subconglobata, , . ;~ A. spinuloinj/ata• • i :.i. Ctlx.lrardinagae
iii
Clio cubensis
I":: Gnu. IOZf1llOi' " '. Glen. index index
i ., :,... "Gds". /rigginsi, , , ':':.
~ ~ •Plla. m~cra.
~ ,!!~ Plla. "!,lcoxensls• ~ M. spmulosa• • , .. i+ Tds. col/aclea
Tds. /opilensis
10m' :: ::::
I

• ••
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: : : A::, . co:,"A. soldadoensis :• '',........ M. ,'elascoensis parva
Z aegypliaca• '.
..
, S. maequlsptra,S.bakeri

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• 'M. con;cotrWJcata• A. pentacamerata pnetacamerata• S. pseutioeocaenQ':• :M. simuialilis: • M. velascoensis veiascotllsis
;:
'

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Formation•t..

Ch. martini
t:: Gna. officinalis.;: M. bandyi':: P. pseutloscitula"':: S. yeguaensis~ M.lehneri::, Cds. echinatus• • • :: A. aspensis• : ": Cds. simulans

II ••

~

Gka. subconglobata

AlfdlJ.lg!llJ.llS0Jq /lJ.lal!U!UJlJ.loj J!UOP!UlJ/d auagoa/lJcl

"m
'frL6

524

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

exposed at Gebel Aweina, south of Luxor.
The Esna Formation is distributed at theeastern margin of the study area, 140 km eastof El Sheikh Fadl village (Section 11). At
this locality, it is composed of gray to darkgray, soft to moderately hard, gypsiferous
shale. The thickness is approximately 5 m(Figure 2).
2.

The Thebes Formation
The Thebes Formation was originallyintroduced by Said (1960) from the Gebel
Gurnah locality, opposite Luxor. The nameis applied to a 290 m-thick limestone section,with intercalations of many chert bands,
which overlies the Esna Shale at Thebes.
In the investigated area, the Thebes Formation is observed at two outcrops, 127 and 140
km east of El Sheikh Fadl village (sections 10
and 11). At section 10, it spans the whole
thickness of the section and is about 25 m inthickness, while at section II it occupies theuppermost 5 m and overlies a shale unit (Figure 2). The rocks are yellowish white, hard
limestone, showing a papery structure on
weathered surfaces. This limestone is accompanied characteristically by dark brownchert nodules arranged horizontally in parallel bands.
3.

The Maghagha Formation
The uniit was first proposed by Bishay(1966) to designate a chalk-marl complex
exposed in Maghagha district in the Nile
Valley. The Maghagha Formation is considered to be coeval with the Samalut Formation
which represents the lowermost lithostratigraphic unit of the Mokattam Subgroup in
Egypt (Said, 1990).
In the study area, the Maghagha Formation
is exposed at sections I (the type section as
designated by Azab (1984», 3,4, and 5 (Figure 2). It consists of alternating beds ofwhite, moderately hard, chalky limestone,
and grayish white to yellowish white, soft tomoderately hard marl. The Maghagha Formation attains its maximum thickness(approximately 81.30 m) in the study area insection 1.
4.

The Qarara Formation
The name of the Qarara Formation was
introduced by Bishay (1966) to designate thesequence exposed at Gebel Qarara opposite
Maghagha. This sequence is composed ofquartzose calcareous sandstone and clay with
abundant nummulites and macrofossils(Azab, 1984).
In the study area, it is represented by yellowish white, very hard calcareous sandstones
and greenish white to gray, moderately hard
shales. Macrofossils and nummulites areabundant. This sequence occurs in sections
2,6,7,8, and 9, and attains its maximum
thickness of about 91.30 m in section 6 (Figure 3).
5.

The EI Fashn Formation
The name of this rock unit, typically
exposed at EI Fashn, was also introduced by
Bishay (1966) for a sequence of limestone
beds rich in nummulites and bryozoans,which intercalate with chert bands near thebase. This sequence overlies disconformably
the Qarara Formation (Said, 1990).
In the study area, the El Fashn Formationconsists of white limestone with chert bands
and is rich in nummulites and bryozoans.
Planktonic foraminifers and ostracodes arerare in this formation. The El Fashn Formation crops out at the top of exposures in
sections 6, 7, 8 and 9, attaining a maximum
thickness of about 20 m in section 6 (Figures
2,3).

Methods and Materials
Bulk samples were washed through a 115,urn-opening mesh screen, using water for
shale and sandstone, and hydrogen peroxide(H 2 0 2 ) and water for calcareous rocks.
Specimens studied in this paper wereobtained from splits (using microsplitter)
which contain approximately 200-300 indi-Formation

Qarara':!..

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:

....
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• 'Hna.' cf. bolivariana :• Trt. griffinae : : :

:
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A. bullbrooki
II 'i spinuloinjla;a---ti-;:~. s. !inaperla :"Gds" higginsi
Ch.mar;in;, : i .'
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S.eocaena :H: Oka. mexicana mexicana
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•
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M. lehneri: pi Ctlx. africana: It: M. bandyi: :. Mila. senn;: :+S. yeguaensis; :. Trl. cerroazule,!sis possagnoensis

:4:

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tflfdV.lE!/v.i/sOJq /v.la.l!u!Ulv.loj J!uoJ>/uv/d auaEoa/vd"frL6

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

526

Table 1.

List of planktonic foraminiferal species in the study area.

Iz

I

N36

WI5
Vl5

U2
Ul

x

x

M24

X

X

X X

x

x

NI4 X

x

x

xX

X

x

x
x

x

x x

x

x
x

Nil
V5 X X X

N7
N5
B30

x

x
x x

x
x

x

x

N4

x
x
x
x
x

N3

x

R6 X X

x

N2
RI X Xx

A9 X Xx

S35

Bll X X
S9 X
S6 X

X
X

x

x

x x

x

x

Q6

x

Q2

X
X

x x
x x
x

x

x

x

x
x

x
x

x x

x

S3
T6 X

!21

x

x
x

X X

x

x

x x
x

x

x

x

x

x x

x

X X
X x

x

viduals. All foraminiferal specimens were
picked and identified. Of 297 samples washed, 27 were used in this biostratigraphicalstudy.
Biostratigraphy and planktonic
foraminiferal zonation
The Paleogene rocks in the studied area
yielded rich and diverse planktonic andbenthic foraminifera. Concerning the planktonics, although quantitative analyses ofthese faunas remain to be done, some 70
species and sUbspecies belongng to 17 genera

x
x

x x

x
x
x

x
X

x

x

x x

x

x
x
x x

x

x x

x
x x
x x
x
x

x

x

x
x

x

x

x
x

x

x

x
x
x x

x

x
x
x
x
x

x

were identified (Table I). Their stratigraphic distributions are shown in Figures 2 and3. The sequence of the Esna, Thebes, Maghagha, and Qarara Formations distributed inthis area can be divided biostratigraphicallyinto the following five biozones in ascendingorder which range in age from the latePaleocene to middle Eocene (Figures 4,5) :the Pia norotalites pseudomenardii Zone,
Acarinina aspensis Zone, Globigerinatheka
subconglobata Zone, Morozovella lehneri
Zone, and Truncorotaloides rohri Zone.
The zonal marker species are selected andthey are shown in Figures 6, 7 and 8.

974.

Paleogene planktonic foraminiferal biostratigraphy
Table 1.

VIS

X

U2

X

UI X

X

NI4
Nil

X

X

VS
N7

(continued)

X

X

X X
X X
X X
X X

X

X

X X X
X
X

X

X
X

X X

X

X

x
X

X

X X X

X

X

NS

X

X X

B30 X
N4

X
X

X

X
X
X

X

N3 X
R6 X

N2
RI
A9

X

S3S

X

Bl1
S9
S6
S3
T6
Q6

527

X

X
X

QI

X X X

X

X

X

X

X X

X X
X X X

X X
X X

X

X X

X
X
X

Two representative Paleogene zonations
have been proposed in low-latitude regions.
One is the zonal scheme proposed by Bolli(1957a, b), and subsequently modified by
Bolli (1966) and Toumarkine and Luterbacher (1985). The other is the P-zone system
and its revised versIOns (Blow, 1969, 1979;
Berggren, 1969b, 1969c; Berggren and Miller,
1988) (Figure 5). Because the Paleocene
fauna obtained from the studied area abundantly contains zonal marker species characteristic of tropical and subtropical waters, thePaleocene zonation recognized here can easily be correlated with internationally recog-

X

X X

X X
X X X
X

X

X X
X X
X X
X
X
X X
X
X
X X X

X X
X X

X

X
X

X
X

X
X
X
X
X

X X
X

X X
X X

X

Q2

X X
X X
X X
X X
X X
X X
X X
X X
X X
X X

X X
X X
X X
X X
X

X X

X

X

X X X

X

X

X

x

X X X

nized zonal scheme. The middle Eocene
faunas, however, lack index species such as
Hantkenina nuttalli, Morozovella aragonensis, and Orbulinoides beckmanni, whose
datum levels are used to define the top andbase of the zones in these two standard lowlatitude zonations. The absence of important index species has also been reported inother Egyptian sequences (Haggag 1985,
1989a, 1989b; Haggag and Luterbacher,1991), and has led to a difficulty in correlating
the Egyptian Eocene zones with the international zonal schemes. In this paper, we
describe five regional zones applicable to the528

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki
678--------------F9"---

15

G

Marl

D

Calcareous sandstone

I2G2I Sandt clayey limestone~~~

Sandt limestone
Clayey limestone_

Sandy shale
Calcareous shale

•

Shale

~

Urnestone

11

m~
-QI

Figure 4. Biostratigraphic correlation of the Paleogene sequence distributed in the studied area basedon planktonic foraminiferal zones.

studied sections, and discuss their characteristics and regional and international correlations.

1.

Planorotalites pseudomenardii
Assemblage-Zone
Definition: This zone is defined by the occurrence of Planorotalites pseudomenardii(Bolli). The top and base are not firmly
defined in the studied area because of the lackof adequate section.
Characteristic species: In addition to thezone nominal species, this zone is character-ized by the common occurrences of Morozovella velaseoensis as three subspecies (M.
velaseoensis aeuta, M. velaseoensis velaseoensis, and M. velaseoensis parva). Other diagnostic species in the middle and latePaleocene interval are Planorotalites pusillapusilla (Bolli), P. albeari (Cushman and
Bermudez), Chiloguembelina midwayensis
midwayensis (Cushman), Zeauvigerina
aegyptiaea Said and Kenawy, Morozovellaangulata (White), M. eonieotruneata (Subbotina), and M. oec/usa oec/usa (Loeblichand Tappan).

974.

Paleogene planktonic foraminiferal biostratigraphy529

Gka. semUnvoluta

P15

Tds. rohri

Tds. rohri

Biohorizon 3

P14

Tds. rohri
M. fehneri s. I.

Biohorizon 2

M.lehneri

P12

Gka. s. mbconglobala

P11

H. nUl/alii

P10

M.lehlleri
Ola. subconglobma

Biohorizon 1

A. bullbrooki

A. aspensis

f - - - _ _ _ _-+_______~~HantkfJn,.na

52.0

P9
f---=----+~PlanorotBlit8s palmer8s 53.4-------+--....!..~---__+-e Acarinins pentacamerata

Morozovella formosaP7- - - - - - - + - - - - - - - . - - + - " Morozovella aragonensis 55.2
M. subbolinae
M. edgari

P6
Morozovella vslascoensis 57.8

M. velascoensis-------+--...:....=-------+~ PlanorotaU'fls pssudomenardii 58.8

Pl. pSt'udomenordii

P/anorotalites comprsssus 64.5
Subbotina prafICursoria

P1
S. pseudobuttoides. . Undefined or unrecognized zonesb• Datum levels based on Toumarkine and Luterbacher (1985)

Figure 5. Correlation of planktonic foraminiferal zones of the studied area with the standard
low-latitude zonations and other Egyptian zones. Age and epoch boundaries are adopted from Berggren
et al. (1985) and Aubry et al. (1988).

530

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

Occurrence: Esna and Thebes Formations in
section II (Figures 2, 4).
Correlation and age: Many workers considered Planorotalites (= Globorotalia)
pseudomenardii to be an easily recognizable
species and an excellent marker species of thelate Paleocene (Bolli, 1957a; Berggren,1969b, 1969c; Luterbacher, 1975; Stainforth
et al. 1975; Toumarkine and Luterbacher,
1985; Berggren and Miller, 1988). However,Blow (1979) reported a longer stratigraphic
range of this specis with its occurrence extending upward into the early Eocene Zone P7.
The faunal assemblages occurring in thestudied sections abundantly contain acarinidand morozovellid forms indicative of the latePaleocene, and include no such early Eocene
zonal markers as Morozovella marginodentata, M. subbotinae, or M. formosa.
Therefore, the P. pseudomenardii Zone recognized in the Esna Formation can be correlated exactly with Zone P4. The age of thiszone is late Paleocene (Selandian) (Figure 5).

2. Acarinina aspensis Partial Range-Zone
Definition: Partial range of the nominate
taxon, but the base is not clearly defined in
the studied sections. The top is marked by
the initial appearance of both Globigerinatheka mexican a kugleri and G. mexicana mexicana.
Characteristic species: This zone is characterized by common to abundant occurrences ofAcarinina pentacamerata pentacamerata
and its related forms (Acarinina aspensis, A.
pentacamerate camerata, and A. colomi).
The zonal marker species is accompanied by

Acarinina soldadoensis, A. bullbrooki (Bolli),
A. spinuloinjiata (Bandy), Globigerina lozanoi
Col om, "Globigerinoides" higginsi Bolli,
Morozovella spinulosa (Cushman), Pseudohastigerina spp. and Subbotina inaequispira(Subbotina).
Occurrence: The Thebes Formation and thelower part of the Maghagha Formation, andthe lower part of the Qarara Formation (Figures 2,3,4).
Correlation and age: As mentioned above,
such early to middle Eocene zonal markers as
Planorotalites palmerae, Morozovellaaragonensis, M. caucasica, Hantkenina spp.,
and Subbotina frontosa are extremely rare orabsent in the studied sequences. Therefore,
the local zones are rather difficult to correlatewith the standard tropical to subtropicalzonal schemes.
Acarinina pentacamerata appears initiallyat the base of Zone P8, which can be correlated with the base of the Morozovella aragonensis Zone defined by Toumarkine and Luterbacher (1985). The last appearance datum(LAD) of this species has, however, considerable uncertainty; it is placed at the top ofZone PIO by Blow (1979), or at a considerably higher level within the Morozovella lehneri Zone by Toumarkine and Luterbacher(1985), which corresponds to Zone Pl2 of
Blow (1979). The occurrence of A.
pentacamerata camerata ranges from Zones
P8b to PIO, while Acarinina aspensis firstoccurs at the top of Zone P9 and disappears
within Zone Pll (Blow, 1979). The first
appearance datums (FADs) of 'Hastigerina'
cf. bolivariana and Turborotalia griffinae~
Figure 6. 1-3, "Globigerinoides" higginsi Bolli, two side and umbilical views, Sample Bll of the
Maghagha Formation; 4-6, Subbotina Jrontosa boweri (Bolli), spiral, side, and umbilical views, Sample B30of the Maghagha Formation; 7-9, Globigerina lozanoi Col om, spiral, side and umbilical views, Sample B30of the Maghagha Formation; 10-12, Acarinina soldadoensis (Bronnimann), spiral, side and umbilical views,
Sample Q2 of the Esna Formation; 13-15, Acarinina mckannai (White), spiral, side and umbilical views,
Sample Q2 of the Esna Formation; 16-18, Acarinina bullbrooki (Bolli), spiral, side and umbilical views,
Sample Bli of the Maghagha Formation; 19-21, Acarinina spinuloinjlata (Bandy), spiral, side and umbilical views, Sample BII of the Maghagha Formation; 22-24, Truncorotaloides rohri Bronnimann and
Bermudez, umbilical, side and spiral views, Sample BII of the Maghagha Formation; 25-27, Truncorotaloides topilensis (Cushman), umbilical, side and spiral views, Sample BII of the Maghagha Formation.
Scale bars= 100 Jim.

974.

Paleogene planktonic foraminiferal biostratigraphy

53 1

532

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

mark the base or just above the base of Zone
P9, whereas Globigerinatheka index index, G.
subconglobata subconglobata, and Subbotina
frontosa boweri first appear at somewhat
higher levels within Zone PIO (Blow, 1979;
Toumarkine and Luterbacher, 1985).
Because of the co-occurrence of otherspecies, the Acarinina aspensis Zone in thispaper can be correlated with the combinedinterval of both Zones P9 and PlO, whichcorrespond to the Hantkenina nuttalli Zone
and the A. pentacamerata Zone of Toumarkine and Luterbacher (1985) (Figure 5).
Such typical middle Eocene representatives as
Acarinina bullbrooki, A. spinuloinjiata,"Globigerinoides" higginsi, Morozovellaspinulosa, and Truncorotaloides spp. are observed frequently in this zone (Figures 2, 3).
The abundant occurrence of A. pentacamerata suggests that the Thebes Formation was
deposited in the latest early Eocene, while the
Maghagha and Qarara Formations are assigned to the middle Eocene, because the G.
subconglobata and G. index groups occur.
The total geological age of the A. aspensis
Partial Range-Zone ranges from the latest
early Eocene to early middle Eocene(Ypresian to Lutetian) (Figure 5).

3.

Globigerinatheka subconglobata IntervalZone
Definition: A zonal interval between theinitial appearance of Globigerinatheka mexicana kugleri, or G. mexican a mexicana(base), and the initial appearance of Morozovella lehneri (top).
Characteristic species: This zone shows afaunal affinity with the underlying, A. aspensis Zone in the composition and abundanceof characteristic species, with the exception of
species belonging to the genus Globigerinatheka. However, globigerinathekids are rare to
few in all the studied sections. In addition,
Acarinina broedermanni (Cushman and Bermudez), Truncorotaloides rohri Bronnimann
and Bermudez and Truncorotaloides topilensis(Cushman) occur commonly in this zone.
Occurrence: The Maghagha and Qarara Formations; the middle part of section I and thelower and middle part of sections 3 to 5
(Maghagha Formation), and the middle partof sections 2, 8, 9 and the lower part of sections 6, 7 (the Qarara Formation) (Figures 2,
3,4).
Correlation and Age: The FADs of
Globigerinatheka mexicana mexican a and G.
mexicana kugleri are found at the base orwithin the Globigerinatheka subconglobata
subconglobata Zone of Toumarkine andLuterbacher (1985). Bolli (1972) originallydefined this zone as being characterized by
the rapid evolution of the genus Globigerinatheka and by the presence of several subspecies of G. subconglobata, G. mexicana andG. index. This interval corresponds to Zone
PII (Toumarkine and Luterbacher, 1985;
Berggren and Miller, 1988). Therefore, thebase of the Globigerinatheka subconglobata
Zone proposed in this paper is correlatablewith the base of Zone PI I or the internationally recognized G. subconglobata subcongobata Zone. However, the top of the latterzone is defined by the LAD of Morozovellaaragonensis, which is not applicable to the~
Figure 7. 1-3, Acarinina broedermanni (Cushman and Bermiidez), umbilical, side and spiral views,
Sample B30 of the Maghagha Formation; 4-6, Acarinina aspensis (Colom), spiral, side and umbilical views,
Sample BII of the Maghagha Formation; 7-9, Acarinina pentacamerata camerata Khalilov, umbilical, sideand spiral views, Sample BII of the Maghagha Formation; 10-11, Acarinina pentacamerata pentacamerata(Subbotina), umbilical and spiral views, Sample T6 of the Thebes Formation; 12-14, Acarinina praeangulata (Blow), spiral, side and umbilical views, Sample QI of the Esna Formation; 15-17, Planorotalites
albeari (Cushman and Bermiidez), spiral, side and umbilical views, Sample QI of the Esna Formation; 18-20, Morozovella conicotruncata (Subbotina), spiral, side and umbilical views, Sample QI of the Esna
Formation; 21-23, Morozovella angulata (White), spiral, side and umbilical views, Sample Q2 of the Esna
Formation; 24-26, Planorotalites pseudomenardii (Bolli), spiral, side and umbilical views, Sample Q2 of theEsna Formation. Scale bars= 100,um.

974.

Paleogene planktonic foraminiferal biostratigraphy

533

534

Hiroshi Nishi, Ashraf M. T. Elewa and K unihiro Ishizaki

present study area because this species isabsent. We instead used the FAD of Morozovella lehneri as a zonal marker because M.
lehneri is a conspicuous species in the middle
Eocene interval. The FAD of M. lehneri has
been recognized in the upper part of Zone
PI! (Blow, 1979) or near the base of the G.
subconglobata subconglobata Zone (Toumarkine and Luterbacher, 1985).
Therefore, the G, subconglobata Zone
established in this paper can be correlatedwith Zone PII or the G. subconglobata subconglobata Zone, and probably corresponds
to the lower part of these zones (Figure 5).
On the other hand, Globigerinatheka index
index and G. subconglobata subconglobata
first appear earlier than G. mexicana subspecies within the lower A. aspensis Zone
(Figures 2, 3). The age of this zone is middle
Eocene (Lutetian).
4. Morozovella lehneri Total Range-Zone
Definition: Total range of the nominal taxon
between the initial appearance of G. mexicana (base) and the last appearance of
Morozovella lehneri (top).
Characteristic species: In addition to
the nominate taxon, diagnostic species of thiszone include Pseudohastigerina spp., Morozovella spinulosa (Cushman), Truncorotaloides collactea (Finlay), T. rohri Bronnimann and Bermudez, T. topilensis (Cushman), "Globigerinoides" higginsi Bolli, andAcarinina spinuloinjlata (Bandy).
Occurrence: The Morozovella lehneri Zone isthinner than other zones in the studied sections. We recognized this zone in the uppermost parts of sections 3, 5, and 6 (Maghagha
Formation), and the lower part of section 7(Qarara Formation) (Figures 2,3,4).
Correlation and Age: Blow (1979) noted that
Morozovella lehneri initially appeared in theupper part of Zone P II and disappeared at
the top of Zone P13, but Toumarkine andLuterbacher (1985) stated that this species
persisted upward to the Middle/Upper
Eocene boundary. The nominate taxon isaccompanied by such age-diagnostic species
as Acarinina aspensis and Morozovella bandyi, which disappear at the top or in theupper part of Zone PI!. The joint occurrence of these species suggests that the Morozovella lehneri Zone established herein canbe correlated with the upper part of Zone P I I
or the Globigerinatheka subconglobata subconglobata Zone of Toumarkine and Luterbacher (1985).
Although Globigerina lozanoi Colom waspreviously seen as a Lower to Middle Eocene
marker species ranging from Zones P8 to PI 0
(Blow, 1979; Toumarkine and Luterbacher,1985), this species ranges upwards to Zone
PI I in the present study. The age is middle
Eocene (Lutetian).

~ Figure 8. 1-3, Morozovella spinulosa (Cushman), umbilical, side and spiral views, Sample R6 of the
Maghagha Formation; 4-6, Morozovella lehneri (Cushman and Jarvis), umbilical, side and spiral views,
Sample R6 of the Maghagha Formation; 7-8, Morozovella oec/usa oec/usa (Loeblich and Tappan), umbilical, side and spiral views, Sample Q2 of the Esna Formation; 10-12, Planorotalites pseudoscitula (Glaessner), umbilical, side and spiral views, Sample Q2 of the Esna Formation; 13-15, Morozovella oec/usa
aeutispira (Bolli and Cita), spiral, side and umbilical views, Sample QI of the Esna Formation; 16-18,
Morozovella velaseoensis parva (Rey), umbilical, side and spiral views, Sample Q2 of the Esna Formation;
19-21, Morozovella velaseoensis velaseoensis (Cushman), umbilical, side and spiral views, Sample Q2 of theEsna Formation; 22-23, Pseudohastigerina wileoxensis (Cushman and Ponton), lateral view and aperturalface, Sample BII of the Maghagha Formation; 24-26, Globigerinatheka subeonglobata subeonglobata(Shutskaya), umbilical and two side views, Sample S35 of the Maghagha Formation; 27-28, Zeauvigerina
aegyptiaea Said and Kenawy, edge and lateral views, Sampe Q2 of the Esna Formation; 29-30, Chiloguembelina erinita (Glaessner), edge and lateral views, Sample Q2 of the Esna Formation; 31-32, Chiloguembelina midwayensis midwayensis (Cushman), edge and lateral views, Sample Q2 of the Esna Formation.
Scale bars= 100 pm.

974.

Paleogene planktonic foraminiferal biostratigraphy

535

536

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

5. Truncorotaloides rohri Assemblage-Zone
Definition: The zonal base is marked by the
F AD of M. lehneri, but the top is not defined.
Characteristic species: Abundant occurrences of Truncorotaloides spp. and A.
spinuloinjlata characterize this zone. Other
representative species include G. higginsi, M.
spinulosa, and A. broedermanni. Planktonic
foraminifers are generally rare, as comparedwith benthic species.
Occurrence: The Qarara Formation in all
sections (Figures 3, 4).
Correlation and Age: Orbulinoides beckmanni has been used to establish the O.
beckmanni Total Range-Zone in the P-zone
system and other zonal schemes (e.g. Stainforth et al., 1975; Berggren, 1969a, 1969b;
Blow, 1979; Toumarkine and Luterbacher,
1985; Berggren and Miller, 1988). The last
occurrence of spinose forms (A carin in a,
Morozovella and Truncorotaloides) characterizes the uppermost Middle Eocene zone, Zone
PI4 or the Truncorotaloides rohri Zone.
The absence of O. beckmanni in the studied area presents a difficulty in correlating ourzones with the international zones as well asother middle Eocene zones. We believe that
our Truncorotaloides rohri Zone here
proposed is correlative with the combinedinterval of Zones Pl2 through P14, but further biostratigraphic work is desired in thisarea. The age of the zone is late middle
Eocene (late Lutetian).
Interregional correlation between the
study area and other regions in Egypt
Paleocene sequence
The Esna Formation (Esna Shale) has beenrecognized in Egypt to be developed in widely separated areas from the Farafra Oases in
the west to the eastern part of the Sinai
Peninsula in the east. This formation showsminor variations in its thickness and lithology, consisting mainly of green and grayshales. The Esna Formation is a conspicuous mappable unit in the Egyptian stratigra1.

phic column. It is overlain by the Tarawan
Formation (chalk beds) and in turn underlain
by the Thebes Formation (hard limestone
beds with many chert concretions). In thetype locality, Said and Sabry (1964) recognized six biozones of planktonic foraminifers
corresponding to the interval from Zones P3
to P6 of Blow (1979).
On the other hand, Said (1960) describedand illustrated the following early Eocene
planktonic foraminifera from the type locality of the Thebes Formation: Globorotalia
planoconica Subbotina, G. conicotruncata(Subbotina), G. thebaica (Said), G. imitata
Subbotina, Hastigerina aspera (Ehrenberg),
H. micra (Cole) and Globigerina
triloculinoides Plummer. Said (1990) also
demonstrated that the Thebes Formation encompasses planktonic foraminiferal biozones
ranging from Zones P6b to PIO (i.e. early
Eocene in age).
The approximately 11 m sequence exposedin section II consists of gray shale in thelower part and limestone beds in the upper.
These two types of rocks, correlated with thelower part of the type Esna Formation, yield
abundant planktonic foraminifers which areassignable to Zone P4. Zone P4 (Planorotalites pseudomenardii Zone) is a wellknown unit traceable in Egypt from theWestern Desert to Sinai regions (Said and
Kenawy, 1956, 1961 ; Said and Sabry, 1964;
Beckmann et al., 1969; Abdel-Kireem et al.,
1985; Said, 1990; Shahin, 1992), and also
outside of Egypt in such regions as V.A.E.
(Anan and Hamdan, 1993), Saudi Arabia(EI-Khayal, 1974), Libya (Berggren, 1969a),
Israel (Benjamini, 1980), and Syria (Bolli andKrasheninnikov, 1977). Although theThebes Formation has been considered to beearly Eocene in age by many workers, ourbiostratigraphic work indicates that theThebes Formation includes an upper
Paleocene sequence and ranges in age fromlate Paleocene to early Eocene.

974.
2.

Paleogene planktonic foraminiferal biostratigraphy

Eocene sequence
Beckmann et al. (1969) discussed the age
and geographical distribution of planktonic
foraminiferal zones in Egypt, and describedeight zones starting from the Globorotalia
subbotinae Zone upwards to the Truncorotaloides pseudodubia Zone, all of early to
middle Eocene age. The sections located in
the Western Desert region contain successively all these zones, but several zones have notbeen recognized in the Eastern Desert, Nile
Valley, and Sinai areas where regional biostratigraphic zonal schemes have been used
(Haggag, 1985, 1986, 1989a, 1989b, 1990;
Haggag and Luterbacher, 1991)
Haggag (1989a) summarized a series of her
biostratigraphic works, and divided Middle
Eocene rocks exposed in the Nile Valley into
three biostratigraphic units (Biohorizons 1,2
and 3) using the FADs of Morozovellaaragonensis, Turborotalia cerroazulensis
frontosa, and T. cerroazulensis possagnoensis.
These intervals can be correlated approximately with the tropical to sUbtropical zones
of Toumarkine and Luterbacher (1985) asshown in Figure 5. In the Sinai Peninsula,
Haggag and Luterbacher (1991) modified thestandard low-latitude zonation by using the
F AD of Acarinina bullbrooki and the FAD
of Globigerinatheka subconglobata rubriformis to define their zonal boundaries
instead of FADs of Hantkenina spp. andGlobigerinatheka mexicana mexicana.
They proposed three new zones, the Acarinina bullbrooki Zone, the Globigerinatheka
subconglobata subconglobata Zone, and the
Morozovella lehneri s.l. Zone, in ascendingorder, which collectively correspond to aninterval from Zones PI 0 to P 13 of Blow
(1979). On the other hand, the uppermost
middle Eocene zones established in the Nile
Valley were well correlated with the standard
Paleogene zonal sequence from Zones PI4
and P 15 or the Truncorotaloides rohri Zoneof Toumarkine and Luterbacher (1985) (Haggag, 1985; Abdel-Kireem, 1985).
An attempt at interregional correlation

537

between the zones established here and othermodified Egyptian zones in the middle
Eocene interval from Zones PI 0 to P 13 presents some difficulty because of the different
stratigraphical ranges of some marker species.
For example, Morozovella lehneri became
extinct in the study area at a level lower thanin Sinai and the Nile Valley. Morozovellaaragonensis and Turborotalia cerroazulensis
and its subspecies occur commonly in Sinai
and the Nile Valley, but they are rare orabsent in the studied sections. In the Eastern
Desert sequences, these plankton fossils occur
in various lithofacies, each of which wasgiven various formational names by different
authors. The complexities of lithology ofthe middle Eocene sequence may be ascribedto the development of isolated sedimentarybasins in shallowing seas. The retreating sea
shifted the shoreline northwards, near to theregion of Minia during early and middle
Eocene times (Said, 1990). Accordingly,
some plankton faunas (e.g. Morozovellaaragonensis, M. lehneri and Orbulinoides
beckmanni, all considered to be dwellers ofdeeper waters than acarinid species) are scarceor entirely absent in the Eastern Desert where
the studied sections are located, whereas sediments in the Western Desert and the Sinai
Peninsula were deposited at greater depths,
commonly inhabited by morozovellid forms(Haggag, 1989a; Haggag and Luterbacher,1991).
Based on our biostratigraphy, the Maghagha and Qarara Formations are isochronous,
and range from the Acarinina aspensis to
Truncorotaloides rohri Zones, but the stratigraphic interval from the A. aspensis to M.
lehneri Zones is thicker in the Maghagha
Formation than in the Qarara Formation(Figure 5). Such a stratigraphic setting suggests that I) the limestone-marl facies in thewest (the Maghagha Formation) grade laterally into the sandstone-shale facies in the east(the Qarara Formation), 2) the rate of sedimentation was considerably higher in thewest than in the east during early middle

538

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

Eocene time (A. aspensis to M. lehneri Zone
interval), and 3) the deep depositional center
shifted eastward in the late middle Eocene ( T.
rohri Zone).

Species list and taxonomic notes
Paleocene through middle Eocene taxa
identified in the studied sections are listed
below. Additionally, comments are appended to some taxa to clarify morphologicalfeatures that are valuable for species
identification and to record their stratigraphic
occurrences. Because of space limitations,
we only illustrate zonal marker species or
those taxa characteristic of the establishedzones. Synonymies are limited to originalreferences plus some additional references
effected taxonomic change or provided highquality illustrations.

Acarinina aspensis (Colom) (Figures 7-4-6)
Globigerina aspensis Colom, 1954, p. 151, pl,3, figs.
I -35, pI. 4, figs. I -3\.
Globorotalia aspensis (Colom). Postuma, 1971, p.
174-175.
Acarinina aspensis (Colom). Hillebrandt, 1976, p.
340, pI. 5, figs. 8, 12, 13; Blow, 1979, p. 908-91 I, pI.
148, figs. 7-9, pI. 153, figs. 5-6, pI. 157, figs. 1-6, pI.
165, figs. 5-6, pI. 203, fig. 6.

Forms morphologically related to A carinina pentacamerata are listed by several
workers. The following species are
identified in our materials; A. pentacamerata, A. camerata, A. aspensis, A. pentacamerata (Subbotina) var. acceleratoria, and A.
colomi.
Acarinina aspensis is characterized by having 5 to 7 subglobular chambers in the lastwhorl and possessing a Globorotalia-like,umbilical-extraumbilical aperture. Most of
specimens obtained from the studied samples
have 5 chambers, rarely 6 in the last whorl.
This species is distinguished by possessing anaperture situated in a fairly extraumbilicalrather than umbilical position. In the study
area, this is one of the representative speciesof the early middle Eocene faunas.

Acarinina broedermanni (Cushman and Bermudez) (Figures 7-1-3)
Globorotalia (Truncorotalia) broedermanni Cushman
and Bermudez, 1949, p.40, pI. 7, figs. 22-24.
Globorotalia broedermanni Cushman and Bermudez.
Bolli, 1957b, p. 167, pI. 37, figs. 13a-c.
Globorotalia (Acarinina) broedermanni broedermanni Cushman and Bermudez. Blow, 1979, p. 91 1914, pI. 148, figs. 1-3, pI. 153, figs. 7-8, pI. 179, figs.
3-5.

This species has a low trochospiral,biconvex test with nearly circular equatorial
periphery. Chambers in the last whorl number 6 or more, and increase very gradually insize.

Acarinina-IS)bullbrooki

Bolli(Figures 6-16

Globorotalia bullbrooki Bolli, 1957b, p. 167, pI. 38,
figs. 5a-c; Postuma, 1971, p. 180-18\.

Intermediate forms between Acarinina bullbrooki and A. spinuloinflata are recognized.
Such forms produced some confusion as totheir taxonomic identity and made it difficult
to determine the FAD and LAD levels ofthese species. Blow (1979) noted that A.
bullbrooki ranges from Zone PSb to Zone
PII, whereas Toumarkine and Luterbacher(l9S5) extended the LAD of this species
upward to the top of P14. A. bullbrooki is
identified here by such features as its lastwhorl consistently comprising 4 chambers
and the acute periphery of the last chamber,as shown by Bolli (1957b) in his holotype
illustrations. The paratype figures (Figures
4a-c of Bolli (l957b» appear to be referable
to Acarinina spinuloinjlata as judged by theirmore rounded shoulder in lateral view. In
the Sinai Peninsula, A. bullbrooki ranges fromthe Acarinina bullbrooki Zone to the Morozovella lehneri s.l. Zone. This range corresponds to an interval from the middle part ofZone PIO to the middle part of Zone PI3(Haggag and Luterbacher, 1991).

Acarinina colomi (Bermudez)
Globigerina colomi Bermudez, 1961, p. 1167, pI. 2, figs.
6a-c.
Acarinina colomi (Bermudez). HiIIebrandt, 1976, p.
344, pI. 5, figs. 1-3, 5-6.

974.

Paleogene planktonic foraminiferal biostratigraphy

This species differs from Acarinina aspensis in having fewer chambers (4 J1 to 5) in thelast whorl and a fairy lobulated equatorial
outline. The range of this species is notexactly known in tropical to sUbtropicalregions.

Acarinina convexa (Subbotina)
Globorotalia convexa Subbotina, 1953, p.209, pI. 17,
figs. 2-3; 1971, p.263, pI. 17, figs. 2-3; Loeblichand Tappan, 1957, p. 188-189, pI. 48, figs.4a-c, pI.
57, figs. 6-7.

This species has a small, tightly coiled,lenticular, equally biconvex test. The test inlateral view displays a rounded to subacutemargin.

Acarinina densa (Cushman)
Pulvinulina crassata Cushman var. densa Cushman,
1925d, p. 300; Ciffelli, 1972, p. 157, 159, figs. la-c.

Acarinina densa is diagnosed by its nearlyflat spiral side and lobulate peripheral margin. The last whorl has 4 7:4 to 5 chambers
and an acute periphery in side view. This
species differs from A. bullbrooki in possessing a greater number of chambers in the lastwhorl and by the lower height of the umbilical side.
Acarinina esnaensis (LeRoy)
Globigerina esnaensis LeRoy, 1953, p. 31, pI. 6, figs.
8-10.
Globorotalia esnaensis (LeRoy). Loeblich andTappan, 1957, p. 189-190, pI. 61, figs.2a-c.

Blow (1979) synonymized this species with
Globorotalia (= Acarinina) wilcoxensis Cushman and Ponton. However, this species isdistinguished from the latter by its slightly
convex spiral side and by having a morerounded peripheral margin in side view. A.
wilcoxen sis ranges from Zone P6a to P8(Blow, 1979), whereas A. esnaensis has beenreported to occur upwards to Zone P14 (Boersma et at., 1987; Premoli-Silva and Boersma,
1988).

Acarinina mckannai (White) (Figures 6-13
-15)
Globigerina mckannai White, 1928, p. 194, pI. 27, figs.
16a-c; Loeblich and Tappan, 1957, p. 181-182, pI.
47, figs.7a-c, pI. 53, figs. la-2c, pI. 57, figs. 8a-c, pI.

539

62, figs. 5-7.
Globorotalia mckannai (White). Bolli, 1957a, p.79,
pI. 19, figs. 16-18; Postuma, 1971, p. 200-201.

This species is characterized by: I) tightly
coiled and dorsally convex test, 2) the lastwhorl having 5 to 6 globular to ovate chambers which increase regularly in size, and 3)
an aperture tending to take an extraumbilicalposition. Blow (1979) assigned this species
to the genus Muricoglobigerina because of its
muricate wall, but other workers placed it
under the genus Acarinina (Berggren, 1977;
Toumarkine and Luterbacher, 1985;
Premoli-Silva and Boersma, 1988). Unfortunately, we cannot resolve this taxonomic
question because of dissolution of the shellsurface of our specimens due to diagenesis.
We herein follow conventional taxonomy,leaving the problem of generic assignment tofuture studies.

Acarinina pentacamerata camerata Khalilov(Figures 7-7-9)
Acarinina pentacamerata (Subbotina) var. camerata
Khalilov, 1956, p.252, pI. 5, figs.6a-c.
Globorotalia (Acarinina) camerata (Khali1ov).
Blow, 1979, p. 917, pI. 135, figs. 6, pI. 156, figs. 5-6.

This subspecies is discriminated from A.
pentacamerata pentacamerata by its broader
aperture, situated in a slightly intraumbilicalrather than extraumbilical position, and byhaving a somewhat loosely coiled test. Blow
(1979) showed this species to range from
Zone P8b to P 10, but in the study area its
LAD level appears to be higher, probably
within Zone PI!.

Acarinina pentacamerata pentacamerata(Subbotina) (Figures 7-10-11)
Globorotalia pentacamerata Subbotina, 1947, p. 128129, pI. 7, figs. 12-17, pI. 9, figs. 24-26.
A carin ina pentacamerata (Subbotina). Subbotina,
1953, p. 233-234, pI. 23, figs. 8a-c; 1971, p. 305,
308, pI. 23, figs. 8a-c.

Subbotina (1947) showed this species tohave a rounded, planoconvex test with aslightly flattened dorsal side and strongly
convex ventral side. Five to eight chambersin the last whorl increase in size gradually.

540

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

The aperture is slitlike and umbilical toextraumbilical in position. A. pentacamerata pentacamerata is distinguished from A.
pentacamerata camerata by having a slitlike
extraumbilical aperture with a narrower umbilicus and its tighter mode of coiling.

Acarinina praeangulata (Blow) (Figures 7-12
-14)
Globorotalia (Acarinina) praeangulata Blow, 1979, p.
942, pI. 82, figs. 5-6, pI. 83, figs. I, 7-8, pI. 85, fig. I,
pI. 87, fig. 2, pI. 212, figs. 1-2.

This species is morphologically close to A.
angulata, but differs in having a less acuteperipheral margin in side view. Blow (1979)
reported this species to range from Zone P2 tothe earlier part of Zone P4.

Acarinina soldadoensis (Bronnimann) (Figures 6-10-12)
Globigerina soldadoensis Bronnimann, 1952, p.9, pI.
I, figs. 1-9; Bolli, 1957a, p. 71, pI. 16, figs. 7-12, p.
162, pI. 35, figs. 9a-c; Postuma, 1971, p. 158-159.
Globigerina cf. soldadoensis Bronnimann. Loeblichand Tappan, 1957, p. 182, pI. 35, figs. 4a-c.

Diagnoses of this species include its
lobulated, low trochospiral test with a nearlyflattened spiral side, depressed, subroundedchambers in the last whorl, and the aperture
tending to take an umbilical position. The
generic position of this species is as yet unsettled. Blow (1979) placed it in the genus
Muricoglobigerina, whereas other workers
maintained the generic assignment to Acarinina. This species has been found to range
from Zone P5 to P9 in tropical regions (Blow,
1979, Toumarkine and Luterbacher, 1985),
but its sUbspecies A. soldadoensis angulosa
disappears in Zone PIO (Boersma andPremo Ii-Silva, 1988).

Acarinina spinuloinfiata (Bandy) (Figures 619-21)
Globorotalia spinuloinjlata Bandy, 1949, p. 122, pI. 23,
figs. la-c.
Globigerina spinuloinjlata (Bandy). Cifelli, 1972, p.
159, pI. I, figs. 2a-c.

This species, one of the conical acarinids
which characterize the middle Eocene faunain the low latitudes, occurs commonly, often

dominantly. The FAD of this species, however, has not been evaluated fully, although it
has been placed either within Zone PII (Boersma and Premoli-Silva, 1988) or within Zone
PI2 (Blow, 1979). This species is distinguished from Acarinina bullbrooki and Acarinina densa by its last chamber having arounded periphery.

Catapsydrax africana (Blow and Banner)
Globigerinita africana Blow and Banner, 1962, p. \05\06, pI. 15, figs. a-c.
G/obigerinita echinatus africana Blow and Banner.
Blow, 1979, p. 1336-1337, pI. 24, pI. 240, fig. 8.

Blow (1979) used the generic name
Globigerinita for bullate forms of the
Paleogene species and stated that the genus
Catapsydrax is a synonym of Globigerinita.
Many subsequent workers, however, separated these two genera phylogenetically on
account of differences in their ultrastructure,
stratigraphic distribution, and taxonomic
relations.
The bullae of this species are slightly
inflated, moderate in size, with three accessory
apertures. Although Blow (1979) included
this species in the genus Globigerinita, its wall
structure is coarse-pitted and is different fromthe typical smooth surface characteristic of
Globigerinita glutinata (Egger). Our specimens of C. africana have a low trochospiraltest with 3 to 4 chambers in the last whorl,
and their wall structure is coarse-pitted, neither cancellate nor hispid. Herein we classify this species in the genus Catapsydrax.

Catapsydrax echinatus (Bolli)
Catapsydrax echinatus Bolli, 1957b, p. 165, pI. 37,
figs.2a-c.

Catapsydrax hardingae (Blow)
Globigerinita hardingae Blow, 1979, p. 1338-1340, pI.
178, figs. 1-5.

This species is morphologically similar to
Globigerinita martini Blow and Banner, but isdistinguished by its more slowly enlarging
last chamber, more lobulated equatorial margin, and smaller bullae with an infralaminal
aperture. Blow (1979) noted the stratigra-

974.

Paleogene planktonic foraminiferal biostratigraphy

phic range of this species to extend from
Zones PIO to P12.
Catapsydrax simulans (Bermudez)
Catapsydrax cr. dissimilis (Cushman and Bermudez).
Bolli, 1957b, p. 166, pI. 37, fig. 6.
Globigerina simulans Bermudez, 1961, p. 1198, pI. 6,
fig. la.
Globigerinita simulans (Bermudez). Blow, 1979, p.
1343-1345, pI. 186, figs. 6-7.

This species resembles Catapsydrax dissimilis dissimilis and C. dissimilis riveroae, in
having a small, tubelike to rectangular bulla.
The former possesses a single small infralaminal opening at the posterior margin of
the bulla, and the latter has a lower trochospiral test.

541

association with C. cubensis. Beckmann(1957) reported C. martini to range from the
Globorotalia (= Morozovella) aragonensis
Zone to Globorotalia cocoaensis Zone of lateearly Eocene to late Eocene age.
Chiloguembelina midwayensis midwayensis(Cushman) (Figures 8-31-32)
Giimbelina midwayensis Cushman, 1940, p. 65, pI. II,
fig. 15.
Chiloguembelina midwayensis midwayensis (Cushman). Beckmann, 1957, p. 90, pI. 21, figs. la-b.

This biserial species has a fairly elongate
test and obliquely running sutures to the axial
direction. This species is restricted to the
Paleocene (Beckmann, 1957).
Globigerina lozanoi Colom (Figures 6-7-9)

Chiloguembelina crinita (Glaessner) (Figures
8-29-30)
Giimbelina crinita Glaessner, 1937b, p. 383, pI. 4, fig.
34.
Chiloguembelina crinita (Glaessner). Beckmann,
1957, p. 98, pI. 21, figs. 4a-b.

This species is distinguished from
Chiloguembelina midwayensis by having
more globular and more rapidly enlarging
chambers. This species ranges from the baseof the Globorotalia (= Planorotalites)
pseudomenardii Zone to the middle part of
the Globorotalia (= Morozovella) velascoensis
Zone (Beckmann, 1957).
Chiloguembelina cubensis (Palmer)
Giimbelina cubensis Palmer, 1934, p. 74, text-figs. 1-6.
Chiloguembelina cubensis (Palmer). Beckmann,
1957, pI. 21, fig. 21, text-figs. 14-5-8.

This is one of the small biserial species, andhas a long stratigraphic range from the Porticulasphaera (= Globigerinatheka) mexican ato Globorotalia opima opima Zone of late
middle Eocene to early Oligocene age (Beckmann, 1957).
Chiloguembelina martini (Pijpers)
Textularia martini Pijpers, 1933, p. 57, figs. 6-10.
Chiloguembelina martini (Pijpers). Beckmann, 1957,
p.89, pI. 21, fig. 14, text-figs. 4-8-11, 14-18, 20-23.

This characteristic Eocene chiloguembelid
occurs abundantly in low-latitude regions in

Globigerina lozanoi Colom, 1954, p. 149, pI. 2, figs. 148; Blow, 1979, p. 854-855, pI. 145, figs. 2-9.
Globigerina (Eoglobigerina) lozanoi Colom. Hille.
brandt, 1976, p. 336, pI. 3, figs. 8-17.

This species is characterized by having a
relatively large number of chambers (up to 6)
in the last whorl and by its high, slightly
irregular trochospiral coiling. "Globigerinoides" higginsi Bolli resembles this species,
but shows a more loosely coiled and hightrochospire. Many workers (Hillebrandt,
1966, Blow, 1979, Toumarkine and Luterbacher, 1985, and Haggag, 1989a) consider G.
lozanoi to be an ancestral form of" G." higginsi. This species is reported to range from
Zone P8 to PIO in the literature (e.g. Blow,
1979), but in the studied sections the species
ranges to the upper part of Zone PI \.
Globigerina officinalis Subbotina
Globigerina officinalis Subbotina, 1953, p.78, pI. II,
figs. 1-7; 1971, p. 105, p. 108, pI. II, figs. 1-7 ;Blow and Banner, 1962, p.88, pI. 4, A-C, fig. 16.

Although Blow (1969) noted the range ofthis species as Zone P13 to P22, we believe the
F AD of this species occurred earlier, probably in the later part of Zone PII because of
its rare occurrence in the basal part of the M.
lehneri Zone in the Maghagha Formation.
Globigerina parva Bolli
Globigerina parva Bolli, 1957b, p. 108, pI. 22, figs.
14a-c.

542

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

The lobulated last whorl having consistently 4 chambers and fairly high trochospiralcoiling are the most important morphologicalcharacteristics of this species. This species
closely resembles G. ojJicinalis, but the latterhas a narrow umbilicus.

Globigerinatheka subconglobata subconglobata (Shutskaya) (Figures 8-24-26)

Globigerinatheka index index (Finlay)

Although Berggren and Miller (1988)
contended that the G. subconglobata group,
including three SUbspecies (subconglobata,euganea and curryi) could not be recognizedby the manner proposed by Proto Decima
and Bolli (1970), we herein follow theclassification of Bolli (1972) because the G.
subconglobata group can be discriminatedfrom other globigerinathekid groups by its
large, globular test, robust wall and occasional presence of bullae. G. index has amorphological affinity to G. subconglobata,but differs in having a more elongate test
outline, loosely coiled test, deeply incisedintercameral sutures, and distinct apertures
usually not covered by bullae.

Globigerinoides index Finlay, 1939a, p. 125, pI. 14, fig.
85, fig. 86-88; Hornibrook, 1958, pI. I, figs. 11- 13,
fig. 14.
Globigerapsis index (Finlay). Bolli, 1957b, p. 165,
pI. 36, figs. 14-18.
Globigerinatheka (Globigerapsis) index index (Finlay). Jenkins, 1971, p. 187-188, pI. 22, figs. 642645.
Globigerinatheka index index (Finlay). Bolli, 1972,
p. 124, pI. I, figs. 1-4, text-figs. 51-57,63, and 64.

The FAD of this species is placed within
Zone PIO or the G. subconglobata Zone
(probably Zone Pll) (Blow, 1979; Toumarkine and Luterbacher, 1985).

Globigerinatheka mexicana kugleri (Bolli,
Loeblich and Tappan)
Globigerapsis kugleri Bolli, Loeblich and Tappan,
1957, p. 34, pI. 6, figs. 6a-c; Postuma, 1971, p. 138139; Bolli, 1972, p. 128-129, pI. 2, figs. 6-7, textfigs. 12-17.

This species is discriminated from G. mexicana mexican a by the more loosely coiled,more globular chambers and a less compact
test shape. The two subspecies (kugleri andmexicana) occur in the G. subconglobata
subconglobata Zone which is coeval with
Zone P II of Blow (1979). The former subspecies disappeared within Zone P13, whereas
the latter survived until Zone PI5 or the
Globigerinatheka semiinvoluta Zone of late
Eocene age.

Globigerinatheka mexican a mexican a (Cushman)
Globigerina mexicana Cushman, 1925b, p.6, pI. I,
figs.8a-b.
Globigerapsis mexican a (Cushman). Blow andSaito, 1968, text-figs. 1-4.
Globigerinatheka mexican a mexican a (Cushman).
Bolli, 1972, p. 129-131, pI. 2, figs. 1-5, pI. 4, figs. 16, text-figs. I-II.

Globigerinoides subconglobatus Chalilov var. subconglobata Chalilov, Shutskaya, 1958, p.86-87, pI. I,
figs. 4-11.
Globigerinatheka subconglobata subconglobata (Shutskaya). Bolli, 1972, p. 134, pI. I, figs. 8-10, 15-16"Globigerinoides" higginsi Bolli (Figures 6-1-3)"Globigerinoides" higginsi Bolli, 1957b, p. 164, pI. 36,
figs. Iia-b; Blow, 1979, p. 862-864, pI. 183, figs. 79, pI. 184, figs. 1-7.

"Globigerinoides" higginsi is easily
identified by its loosely coiled and very hightrochospiral test, and moderately to rapidly
enlarging chambers in the last and penultimate whorls. A supplementary aperture is
not always observed except in the last whorl.
The wall structure is microgranular, not cancellate like Neogene Globigerinoides.
Although its generic position remains questionable, this species commonly occurs in thelower to middle Eocene of the low-latitude
area. This species ranges from the base ofZone P9 to PII, but also occurs rarely in thelower part of Zone PI2 (Blow, 1979;
Toumarkine and Luterbacher, 1985).
Guembelitria columbiana Howe
Giimbelitria columbiana Howe, 1939, p. 62, pI. 8, figs.
12-13.

Beckmann (1957) observed this species

974.

Paleogene planktonic foraminiferal biostratigraphy

from the Hantkenina aragonensis Zone to
the Porticulasphaera (= Globigerinatheka)
mexican a Zone, referable to Zones PI 0 to
PII of Blow (1979).

Hantkenina mexicana Cushman
Hantkenina mexicana Cushman, 1925a, p. 3, pI. 2,
fig. 2; Bronnimann, 1950, p. 405, 407, pI. 55, figs.
1-6.

The FAD of the earliest member of thegenus Hantkenina, H. nuttalli, has been used
to mark the Early/Middle Eocene boundary
in low-latitude regions (Blow, 1969; Berggren, 1969a, b; Stainforth et al., 1975;
Toumarkine and Luterbacher, 1985; Berggren and Miller, 1988). Species of Hantkenina occur rarely or are entirely absent in
the studied sections.

'Hastigerina' cf. bolivariana (Petters)'Hastigerina' cf. bolivariana (Petters). Toumarkine
and Luterbacher, 1985, p. 127, 7-12 in fig. 27.

Hastigerina bolivariana (Petters) isdiagnosed by its globular test which is completely involute on the ventral side and nearly
so on the dorsal side, as figured by Petters(1954). 'H.' cf. bolivariana described by
Toumarkine and Luterbacher (1985) has amore compact, less planispirally coiled test
and a less globular last chamber than Petters'
typical form. Although the generic positionof this species is questionable, we follow thetaxonomy of Toumarkine and Luterbacher(1985) and here use the name 'Hastigerina'
for this species.
Morozovella angulata (White) (Figures 7-21
-23)
Globigerina angulata White, 1928, p. 191, pI. 27, figs.
13a-c.
Globorotalia angulata (White). Bolli, 1957a, p.74,
pI. 17, figs. 7-9; Postuma, 1971, p. 170-171.

This is a characteristic species of the middle
to late Paleocene interval in tropical to subtropical regions. This species has a low trochospiral, angular-conical test, showing acuteto subacute margins in axial view, but lacks atypical peripheral keel. Five chambers in
the last whorl are angular in shape and543

increase gradually in size.

Morozovella bandyi Fleisher
Morozovella bandyi Fleisher, 1974, p.1030, pI. 14,
figs. 3-8.

This species resembles M. spinulosa, but isdistinguished in possessing a dorsal opening(Fleisher, 1974). This diagnostic feature
could not be observed in any specimen
obtained from the studied sections. We here
consider that Morozovella bandyi possesses
constantly 4 chambers in the last whorl ascompared with 5 in M. spinulosa and a moreconvex spiral side than the latter species.
This species ranges from the middle part ofZone PIO to PII or is confined to the G.
subconglobata Zone of Bolli (Fleisher, 1974).

Morozovella conicotruncata (Subbotina) (Figures 7-18-20)
Globorotalia conicotruncata Subbotina, 1947, p. 115,
pI. 4, figs. 11-13, pI. 9, figs. 9-11.
Acarinina conicotruncata (Subbotina). Subbotina,
1953, p.220-222, p1.20, figs. 5-10; 1971, p. 281, p.
284-287, pI. 20, figs. 5a, b, 6-12.
Globorotalia angulata abundocamerata Bolli.
1957a, p.74, pI. 17, figs. 4-6; Postuma, 1971, p.
166-167.

By the possession of large numbers ofchambers (6 to 8) in the last whorl, thisspecies is distinguished from M. angulata.

Morozovella lehneri (Cushman and Jarvis)(Figures 8-4-6)
Globorotalia lehneri Cushman and Jarvis, 1929, p. 17,
pI. 3, figs. 16a-c; Bolli, 1957b, p. 169, pI. 38, figs. 913; Postuma, 1971, p. 198-199.
Globorotalia (Morozovella) lehneri Cushman and Jarvis. Blow, 1979, p. 1002-1003, pI. 188, figs. 1-10,
p1.251, figs. 3-4.

This species· has a low trochospiralbiconvex test, which has a strongly lobulated
periphery frilled with a spiny keel and 6 to 7
chambers in the last whorl. Chambers aretangentially elongated, and the last andpenultimate chambers are nearly equal in size.

Morozovella occ/usa acutispira (Bolli andCita) (Figures 8-13-15)
Globorotalia acutispira Bolli and Cita, 1960, p. 15, pI.
33, figs. 3a-c.
Globorotalia (Morozovella) occ/usa acutispira Bolli

544
and Cita.

Hiroshi Nishi, Ashraf M.T. Elewa and Kunihiro Ishizaki
Blow, 1979, p. 1009-1011.

Morozovella oce/usa differs from M. velascoensis in having a thinner lenticular test andsmall, almost closed umbilicus, and from M.
simulatilis in its less convex spiral side.
Blow (1979) proposed two subspecies in M.
oce/usa (oce/usa and acutispira). The lattersubspecies has of 4 to 4 ~ chambers in thelast whorl and displays a lobulated equatorial
periphery, whereas, in M.oce/usa oce/usa
chambers in the last whorl number more than5.
Morozovella oce/usa oce/usa (Loeblich andTappan) (Figures 8-7-9)
Globorotalia occlusa Loeblich and Tappan, 1957, p.
191, pI. 64, figs.3a-c. not: pI. 55, figs.3a-c (=M.
occlusa acutispira).
Globorotalia (Morozovella) occlusa occlusa Loeblichand Tappan. Blow, 1979, p.1007-1009, pI. 90,
figs. 9-10, pI. 95, figs. 7-10, pI. 96, figs. 1-3, pI. 103,
figs. 4-6, pI. 108, figs. 8-10, pI. 118, figs. 1-7, pI. 213,
fig. 6, pI. 214, figs. 1-6, pI. 215, fig. 5.

Blow (1979) showed that this species ranged from the basal part of Zones P4 to P7,
and assigned it a middle late Paleocene toearly Eocene age.
Morozovella simulatilis (Schwager)cher, 1985), and the middle part of Zone P8(Boersma and Premoli-Silva, 1988).
Morozovella velascoensis acuta (Toulmin)
Globorotalia wilcoxensis Cushman and Ponton var.
acuta Toulmin, 1941, p.608, pI. 82, figs. 6-8.
Globorotalia acuta Toulmin: Loeblich and Tappan,
1957, p. 185-186, pI. 47, figs. 5a-c, pI. 55, figs. 4-5.

Morozovella velascoensis is characterized bya planoconvex test, well developed keel andthickened and spinose collar as the umbilicalshoulder in the last whorl. This species
includes three subspecies (acuta, parva andvelascoensis). M. velascoensis velascoensis
has a large number of chambers, generally
more than 6, in the last whorl, whereas acuta
and parva have fewer such chambers, consistently 5 in the former and 4 to 4 ~ in thelatter.
Morozovella velascoensis parva (Rey) (Figures 8-16-18)
Globorotalia velascoensis (Cushman) var. parva Rey,
1955, p.209, pI. 12, figs. I a-c.
Globorotalia (Morozovella) velascoensis parva Rey.
Blow, 1979, p. 1030-1031, pI. 95, figs. 3-6.

Morozovella velascoensis velascoensis (Cushman) (Figures 8-19-21)

Discorbina simulatilis Schwager, 1883, p. 120, pI. 29,
fig. 15.
Globorotalia simulatilis (Schwager). Luterbacher,1964, p. 665-668, figs. 53-58.

Pulvinulina velascoensis Cushman, 1925c, p. 19, pI. 3,
fig. 5.
Globorotalia velascoensis (Cushman). Bolli, 1957a,
p. 76, pI. 20, figs. 1-3; Loeblich and Tappan, 1957,
pI. 64, figs. 1-2; Postuma, 1971, p.218-219.

Morozovella spinulosa (Cushman) (Figures 81-3)

Muricoglobigerina senni (Beckmann)

Globorotalia spinulosa Cushman, 1927, p. 114, pI. 23,
figs. 4a-c; Bolli, 1957b, p. 168, pI. 38, figs. 6-7.
Globorotalia (Morozovella) spinulosa spinulosa Cushman. Blow, 1979, p. 1013-1015, pI. 182, figs. 1-4,
pI. 197, figs. 1-6.

This is one of the typical species of late
middle Eocene morozovellids and disappeared simultaneously with other hispid species(Acarinina and Truncorotaloides) at or justabove the middle/late Eocene boundary.
However, the FAD of this species is unsettled,having been placed at different levels: thebase of Zone PIO (Blow, 1979), the middle
part of Zone P9 (Toumarkine and Luterba-

Sphaeroidinella senni Beckmann, 1953, p. 394-395, pI.
26, figs. 2-4, text-fig. 20
Globigerina senni (Beckmann). Bolli, 1957b, p. 163,
pI. 35, figs. 10-12.

This species can easily be identified by itsvery tightly coiled and highly trochospiraltest and muricate wall.
Planorotalites albeari (Cushman and Bermudez) (Figures 7-15-17)
Globorotalia albeari Cushman and Bermudez, 1949, p.
33, pI. 6, figs. 13-15; Blow, 1979, p. 883-885, pI. 92,
figs. 4, 8-9, pI. 93, figs. 1-4.
Globorotalia pusilla laevigata Bolli, 1957a, p.78, pI.
20, figs. 5-7.

The genus Planorotalites is characterized

974.

Paleogene planktonic foraminiferal biostratigraphy

by a smaller biconvex lenticular test and its
finely perforate, smooth wall surface texture.
In this study we follow the taxonomy ofToumarkine and Luterbacher (1985) and recognize four species, albeari, pseudomenardii,
pseudoscitula, and pusilla pusilla, all belonging to the genus Planorotalites. Planorotalites albead has a circular equatorial
outline and 6-7 or more chambers in the lastwhorl.

Planorotalites pseudomenardii (Bolli) (Figures 7-24-26)
Globorotalia pseudomenardii Bolli, 1957a, p.77, pI.
20, figs. 14-17; Postuma, 1971, p.204-205.

The axial periphery of the test is acute, with
an imperforate keel. Five chambers in thelast whorl are strongly compressed andincrease rapidly in size.

Planorotalites pseudoscitula (Glaessner) (Figures 8-10-12)
Globorotalia pseudoscitula Glaessner, 1937a, p.32,
text-figs. 3a-c; Subbotina, 1953, p. 261, pI. 17, fig.
I, pI. 16, figs. 17-18; 1971, p. 261-263, pI. 14, figs.
17-18, pI. 17, figs. la-c.
Globorotalia renzi Bolli, 1957b, p. 168, pI. 38, figs.
3a-c.

This species has a small, lenticular, thin,biconvex test with a nearly circular periphery.
Chambers in the last whorl number from 5 to
7, which increase slowly in size. This species
resembles P. albead, but differs in having athinner lenticular test. P. pseudoscitula
ranges from Zones P 10 to P 13, whereas thelatter appeared earlier, occurring from Zones
P3 to P7.

Planorotalites pusilla pusi/la (Bolli)
Globorotalia pusilla pusilla Bolli, 1957a, p. 78, pI. 20,
figs. 8- 10.

The last whorl comprising about 5 chambers, instead of 6-7 as in P. albead, and its
less acute axial periphery are the distinguishing characters of this species.

Pseudohastigerina micra (Cole)
Nonion micrus Cole, 1927, p.22, pI. 5, fig. 12.
Hastigerina micra (Cole). Bolli, 1957b, p. 161, pI.
35, figs. 1-2.
Pseudohastigerina micra (Cole). Blow and Banner,

545

1962, p. 704, fig. 2; Saito and Be, 1964, p. 704, fig.
2.

Pseudohastigerina wilcoxensis (Cushman andPonton) (Figures 8-22-23)
Nonion wilcoxensis Cushman and Ponton, 1932, p. 64,
pI. 8, fig. II.
Pseudohastigerina wilcoxensis (Cushman andPonton). Berggren et al., 1967, p. 278-280, figs. 26.

This species is regarded as the firstplanispirally coiled species in the Cenozoic,
and the Paleocene/Eocene boundary has beendrawn at or just above the FAD of thisspecies (e.g. Berggren, I969a, 1969b; Aubryet al., 1988).

Subbotina bakeri (Cole)
Globigerina bakeri Cole, 1927, p. 33, pI. 4, figs. 12-13.
Globigerina turgida Finlay: Bolli, 1957b, p.73, pI.
15, figs. 3-5.
Subbotina bakeri (Cole): Blow, 1979, p. 1255-1256,
pI. 160, fig. 5.

The genus Subbotina was originallydefined in terms of cancellate wall surface
with funnellike pore pits. Blow (1979) gave
the following diagnostic characters for thisgenus: I) a small umbilicus with asymmetrically umbilical-extraumbilical aperturebordered by a porticus, 2) a trochospirally
coiled test with inflated chambers, and 3)
microgranular wall structure. We used thesecriteria for the definitio'n of this genus.
This species has been recorded from Zones
P8b to PI3 (Blow, 1979).

Subbotina eocaena (Gi.imbel)
Globigerina eocaena GUmbel, 1868, p. 662, pI. II, figs.
109a-b; Subbotina, 1953, pI. 6, figs. 5a-c, pI. 7, figs.
la-c; 1971, p.85, p.88-89, pI. 6, figs.5a-c, pI. 7,
figs. la-c; Hang and Lindenberg, 1969, p. 236-245,
table I, figs. 1-6.

Subbotina frontosa boweri (Bolli) (Figures 64-6)
Globigerina boweri Bolli, 1957b, p. 163, pI. 36, figs.
la-2b; Postuma, 1971, p. 144-145.
Subbotina frontosa bowed (Bolli). Blow, 1979, p.
1266-1268, pI. 175, figs. 7-9.

Subbotina frontosa, including its two subspecies boweri and frontosa, has 3 to 3);2

546

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro [shizaki

chambers in the last whorl, in which the final
chamber is greatly enlarged. A high-archedprimary aperture is located in a slightly
extraumbilical position. S. frontosa boweri
can be discriminated from S. frontosa
frontosa by its nearly circular aperture with ashort lip or rim.

Subbotina frontosa frontosa (Subbotina)
Globigerina frontosa Subbotina, 1953, p.84, pI. 12,
figs. 3a-c. not pI. 12, figs. 4-7c; 1971, p. 113, p. 116,
pI. 7, figs. 3-7.
Subbotina frontosa frontosa (Subbotina): Blow,
1979, p. 1263-1265, pI. 158, figs. 6-7, pI. 162, figs.
10-11, pI. 175, figs. 4-6.

Subbotina hagni (Gohrbandt)
Globigerina hagni Gohrbandt, 1967, p. 324, 326, pI. I,
figs. 1-9.

triloculinoides by its somewhat higher trochospiral test and smaller final chamber. It
is representative of the Paleocene subbotinids.
Subbotina triloculinoides (Plummer)
Globigerina triloculinoides Plummer, 1926, p. 134, pI.
8, figs. lOa-b; Bolli, 1957a, p. 70, pI. 15, figs. 18-20;
Loeblich and Tappan, 1957, p. 183-184, pI. 41, figs.
2a-c, pI. 43, figs. 9a-c, pI. 45, figs. 3a-c.
Globigerina (Subbotina) triloculinoides Plummer.
Jenkins, 1971, p. 163-164, pI. 17, fig. 508.
Subbotina triloculinoides triloculinoides (Plummer).
Blow, 1979, p. 1287-1292, pI. 74, fig. 6, pI. 80, fig. I,
pI. 98, fig. 7.

This is the type species of the genus Subbotina. The last whorl has 3 to 3 12 chambers which increase rapidly in size, and its lastchamber occupies up to half the size of theentire test.

This species is mainly diagnosed by its
umbilical-extraumbilical slitlike aperture.

Subbotina velascoensis (Cushman)

Subbotina inaequispira (Subbotina)

This species is distinguished from other
Paleocene subbotinids by its laterally compressed last chamber.

Globigerina inaequispira Subbotina, 1953, p. 69, pI. 6,
figs. 1-4; 1971, p. 84-85, pI. 6, figs. 1-4.

A low trochospiral test with a strongly
lobulated equatorial periphery and rapidly
increasing globular chambers in the lastwhorl characterized this species. The rangeof this species remains unsettled: from Zones
PII to Pl3 in Blow (1979), from P8 to Pl2 in
Toumarkine and Luterbacher (1985), andfrom P5 to PlO in Boersma and Premoli-Silva(1988).

Subbotina linaperta (Finlay)
Globigerina linaperta Finlay, I939a, p. 125, pI. 13,
figs. 54-56; Hornibrook, 1958, p. 33-34, pI. I, figs.
19-2l.
Globigerina (Subbotina) linaperta Finlay. Jenkins,
1971, p. 162-163, pI. 18, figs. 551-553.

Subbotina pseudoeocaena (Subbotina)
Globigerina pseudoeocaena Subbotina, 1953, p. 66, pI.
4, figs.9a-c, pI. 5, figs. 1-2,6; 1971, p. 79-81, pI. 4,
figs. 9a-c, pI. 5, figs. 1-2, 6.

Subbotina triangularis (White)
Globigerina triangularis White, 1928, p. 195, pI. 28,
figs. la-c; Bolli, 1957a, p. 71, pI. 15, figs. 12-14.

This species is distinguished fromS.

Globigerina velascoensis Cushman, 1925c, p. 19, pI. 3,
fig. 6; Bolli, 1957a, p. 71, pI. 15, figs. 9-1l.

Subbotina yeguaensis (Weinzierl and Applin)
Globigerina yeguaensis Weinzierl and Applin, 1929,
p. 408, pI. 43, figs. la-c; Saito and Be, 1964, p. 702705, fig. 2.

Truncorotaloides collactea (Finlay)
Globorotalia collactea Finlay, 1939b, p.327, pI. 29,
figs. 164-165.
Truncorotaloides collactea (Finlay). Jenkins, 1965,
p. 843-848, figs. 1-27.

Supplementary openings on the spiral side
provide an important diagnostic feature forthe genus Truncorotaloides. Although thisfeature is not always observable in most of
our specimens, this genus can be easily recognized by its angular-rhomboid chambers anddistinctly hispid wall surface.
Some workers assign Truncorotaloides collactea to the genus Acarinina because of theabsence of supplementary apertures (Blow,
1979; Boersma and Premoli-Silva, 1988).
We, however, follow Jenkins (1965), Toumarkine and Luterbacher (1985) and others who

974.

Paleogene planktonic foraminiferal biostratigraphy

placed it in the genus Truncorotaloides.

Truncorotaloides pseudodubia (Bandy)
Globigerinoides pseudodubia Bandy, 1949, p. 123, pI.
24, figs. Ia-c.
Truncorotaloides pseudodubia pseudodubia (Bandy).
Blow, 1979, p. 951-953, pI. 171, fig. 4, pI. 194, figs.
5-6.

This species is morphologically close to T.
rohri and T. collactea. It is distinguishedfrom the former by its more compact, slightly
higher-trochoid coiling and the uniform sizeof the chambers in the last whorl, and fromthe latter in possessing a fairly large test.

Truncorotaloides rohri Bronnimann and Bermudez (Figures 6-22-24)
Truncorotaloides rohri Bronnimann and Bermudez,
1953, p. 818-819, pI. 87, figs. 7-9; Bolli, Loeblichand Tappan, 1957, p.42, pI. 10, figs. 5a-c; Bolli,
1957b, p. 170, pI. 39, figs. 8-12; Postuma, 1971, p.
232-233.

This species has a distinctly hispid test with
5 angular-rhomboid chambers in the lastwhorl, which increase rapidly in size. A
supplementary opening is commonly observed in many specimens. Such subspecies as
guaracaraensis, mayoensis, piparoensis,
haynesi and libyaensis are recognized bysome workers (Bronnimann and Bermudez,
1953; Samanta, 1970; EI Khoudary, 1977).
We also recognized forms assignable to thesesubspecies in our materials, but the definitionof these subspecies needs to be clarified further.

Truncorotaloides topilensis (Cushman) (Figures 6-25-27)
Globigerina topilensis Cushman, 1925b, p. 7, pI. I, figs.
9a-c.
Truncorotaloides topilensis (Cushman). Bolli,
1957b, p. 170, pI. 39, figs. 13-16a-c; Postuma, 1971,
p.234-235.

This species has consistently 4 chambers in
the last whorl, which increase rapidly in size.
This is an index species of the late middle
Eocene in the studied sections.

Turborotalia cerroazulensis(Toumarkine and Bolli)

possagnoensis

Globorotalia cerroazulensis possagnoensis Toumar-

547

kine and Bolli, 1970, p. 139-140, pI. I, figs. 4-9.
Turborotalia cerroazulensis possagnoensis (Toumarkine and Bolli). Toumarkine and Luterbacher,
1985, p. 137, 13-15 in fig. 36.

The presence of 4 to 4 J1 chambers in thelast whorl and a relatively high-arched,umbilical to extraumbilical aperture characterize this species.

Turborotalia griffinae Blow
Turborotalia griffinae Blow, 1979, p. 1072-1075, pI.
96, fig. 8.

This species is distinguished from 'Hastigerina' cf. bolivariana by its more lobulated,loosely coiling mode.

Turborotalia wilsoni (Cole)
Globigerina wilsoni Cole, 1927, p.34, pI. 4, figs. 8-9.
Turborotalia wilsoni (Cole). Toumarkine and Luterbacher, 1985, p. 126, 2-4 in fig. 27.

Toumarkine and Luterbacher (1985) discussed the phylogeny of this species andrelated forms. This group which has 4 globular chambers in the last whorl and a tendency to involute planispiral coiling contains
such forms as Globigerina wilsoni Cole,
Globigerina wilsoni bolivariana Petters, 'Hastigerina' cf. bolivariana (Petters), Pseudohastigerina globulosa Hillebrandt, and Turborotalia griffinae Blow.
T. wilsoni illustrated by Toumarkine andLuterbacher (1985) has a more compact, lesslobulately coiled test with a nearly circularequatorial outline and is slightly less involuteon the spiral side than the holotype figures
given by Cole (1927). The specimens observed in the studied sections are similar inmorphology to illustrations of Toumarkine
and L uterbacher (1985).

Zeauvigerina aegyptiaca Said and Kenawy(Figures 8-27-28)
Zeauvigerina aegyptiaca Said and Kenawy, 1956, p.
141, pI. 4, fig. I; Beckmann, 1957, p. 92, pI. 21, figs.
9a-b, II.

This species can be easily distinguishedfrom other chiloguembelinids in having along apertural neck at the terminal end of thelast chamber. This species occurs only in the
Planorotalites pseudomenardii Zone and548

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

Morozovella velascoensis Zone (Beckmann,
1957).

Acknowledgments

The authors wish to express their sincere
gratitude to Dr. M.M. Azab and Dr. M.H. E1
Dawy, of Department of Geology, Faculty of
Science, E1 Minia University, for their assistance in collecting and preparing theexamined samples. Our best thanks areextended to Prof. T. Saito of Department of
Geoenvironmental Science, Faculty of Science, Tohoku University, and Prof. M.S.M.
Ali of Department of Geology, Faculty of
Science, E1 Minia University, for their kind
help throughout the course of the present
study. This study is largely based on part of
the work carried forward by A.M.T. Elewa
during his stay at Tohoku University as avisiting scientist, which was supported by agrant from the Egyptian Government (Channel System). The authors are deeply
indebted to Mr. Jun Nemoto of Departmentof Geoenvironmental Science, Faculty of
Science,Tohoku University, for printing photographs.
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Elewa, A.M.T. and Ishizaki, K., (1994): Ostracodesfrom Eocene rocks of the EI Sheikh Fadl-Ras

550

Hiroshi Nishi, Ashraf M. T. Elewa and Kunihiro Ishizaki

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- - , 1991: Globigerina pseudoampliapertura Zone, a
new Late Eocene planktonic foraminiferal zone
(Fayoum area, Egypt). N. Jb. Geol. Paliiont.,
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Luterbacher, 1964: Studies in some Globorotalia
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974.

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Saito, T. and Be A.W.H., 1964: Planktonic For-

551

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Paleont., vol. 3, no. 4, p. 384-410, pis. 42-44.
White, M.P., 1928: Some index Foraminifera of theTampico Embayment area of Mexico. Ibid.,
vol. 2, no. 3 and 4, p. 177-215, pis. 27-29 (pt. I),
p. 280-3 I 7, pis. 38-42 (pt. 2).

Hiroshi Nishi, Ashraf M.T. Elewa and Kunihiro Ishizaki

552,Iy/ 1-. 1-:A~ /o'Tif- I-tI!!±i&0)J:$l!J!ffJiMt-~$~fJiMti!¥~·ti1HLs1t:eiIl~:

1-7.. ~ /' ° 7-if- r :l:i!!~O)7...:x:.;(1l!1iip ~ 71 Iv}11 ~«tffJTT oJiJij. (EL Sheikh Fadl road)iSlt~ I;: I;l:. EER;Et, m:lER;Et, ~;Etoli'y;Etip ~ 7;t 0 il~=*O):l:!!!lifF (Esna, Thebes, Maghagha,
Qarara, El Fashn Ii) :b~.1±l L.·n~oo ;:tL~0):l:i!!IiI;l:~ilinE1H'Ls1tE~~~L., ;:tL
~ 0)1tE ~ tJ t I;: Planorotalites pseudomenardii. A carinina aspensis, Globigerinatheka
subconglobata, Morozovella lehneri, Truncorotaloides rohri 0) 5 -:J 0)1tE1iH;: i2S:?tT 0 ;: t:b~-r~ 0 ;:tL~0)1tEwl;l: P4w (~MI!l't~i!!:), P9- lO w (~WlI!l't~i!!::b~~ft~WriwWlMl~i!!:), PlI wr$ (MWli:J:lMMl~i!!:), PII w1:$ CiWWli:J:lMMl~i!!:), P12- 14 w (~Wli:J:lWl
Ml~i!!:) 1;:.ftL.:ftL~.It-r~ 0 tJ 0) t*;t ~tLoo L.t.::b~'?-r, Esnalil;l:~WlI!l't~i!!:,
Thebes Ii 1;l:~WlI!l't~i!!::b' ~ MWlMl~i!!:O):ft!ff!{lli¥~ ~5FT Maghagha Ii t Qarara Ii I;l:, jj!jj~ t tJ i:J:lWlMl~i!!:-r, ~~~f§~f* I;: itJ 0 ;: t :b~rm ~:b' t 7;t '? t.: 000

gg 5kPftli], A.M.T. Elewa, E~OOml

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 175, pp. 553-577, 23 Figs., September 30, 1994

975. DESMOSTYLIAN TOOTH REMAINS FROM THE
MIOCENE TOKIGAWA GROUP AT KUZUBUKURO,SAITAMA, JAPAN*
KEN SHU SHIMADA
Department of Geosciences, Fort Hays State University,
Hays, Kansas 67601, U.S.A.
andNORIHISA INUZUKA
Department of Anatomy, Faculty of Medicine,
University of Tokyo, Tokyo, 113 Japan

Abstract. Fifteen isolated desmostylian teeth from the Godo Conglomerate Member ofthe lower part of the Miocene Tokigawa Group at Kuzubukuro, Higashi-Matsuyama City,
Saitama Prefecture, are described in detail. The fossils belong to two genera, Paleoparadoxia and Desmostylus. Twelve teeth belong to Paleoparadoxia, of which five are confidently
identified as P. tabatai. Paleoparadoxia teeth include the upper canine, MI, M2, and M3,
and lower P3 and M3. Three Desmostylus specimens include a milk canine? and fragmentsof cheek teeth. The significance of the Kuzubukuro specimens is that both genera occur
together in the same stratigraphic unit, although the possibility of one or both being
reworked cannot be discarded. Because a number of shark species and some other marine
mammals, such as pinnipeds and cetaceans, occur in the Godo Conglomerate as well, thelocality is important for reconstructing the paleoecology of the desmostylians.
Key words.
awa Group.

Desmostylus, Japan, Kuzubukuro, Miocene, Paleoparadoxia, teeth, Tokig-

mostylian teeth. Many have been collectedby members of the Kuzubukuro Geology
Club, a regional group consisting of amateur
fossil and mineral enthusiasts. Nearly 20
desmostylian teeth have been recovered froma 16 mx60 m area. Nowhere else in Japan
has such a large number of isolated desmostylian teeth been collected. However, noneof the teeth have been formally described(Inuzuka, 1984, table 2). In the summer of
1990, we were given an opportunity to study
15 of the desmostylian teeth from Kuzubukuroo The fossils belong to two genera,
Paleoparadoxia and Desmostylus. The primary purpose of this paper is to describe these

Introduction
The lower part of the Miocene Tokigawa
Group (Koike et al., 1985) at Kuzubukuro in
Saitama Prefecture is known for its abundant
shark teeth. Horiguchi (1975 ed., 1987 ed.)introduced the site in his geological guidebook, in which he encouraged people tocollect the numerous shark teeth. Collectors
also unearthed marine mammals, such as
cetaceans and pinnipeds. However, the site
is most significant for the occurrence of des"Received June 16, 1993; revised
accepted May 20, 1994

manuscript

553

554

Kenshu Shimada and Norihisa Inuzuka

previously unreported specimens in order to
add to the available information on theseanimals.

~siltstone-=-=- Tuffaceous

1---

t----

+ rE

--

g --=-r----1'---

Geographical and geological settings

1---

Kuzubukuro lies between the Tokigawa
and Oppegawa rivers, two tributaries of the
Arakawa River, in the northeast part of the
Iwadono Hills of Higashi-Matsuyama City,
Saitama Prefecture, central Japan (Figure I).
The Iwadono Hills are located in a structuralbasin. Here the lower part of the Iwadono
Formation of the Miocene Tokigawa Groupis exposed. The Iwadono Formation isdivided into three fining-upward members:
Godo Conglomerate, Negishi Sandstone, andShogunzawa Siltstone members (Koike et al.,1985) (Figure 2). The fossils described here-

,

...

Q)

c:

0
C. :;::;
tV
0

::l

(; E
...
tV

0
LI..

tV
01

0
c:
0

~

:i

{?

"0
tV

.!

.Q

E
Q)
~
Q)

c:

~
"0
c:
tV

LlSJ

Sandstone

(J)

:i:
In

'51
Q)

z

Sandy conglomerate- conglomerate

Figure 2. Generalized geologic column of theTokigawa Group at Kuzubukuro based on Koike
and Takei (pers. comm., 1990). The stratigraphic
range of the desmostylians described in this paper isshown by X.

Figure 1. Locality map showing the positionof Kuzubukuro (fossil site indicated by X), HigashiMatsuyama City, Saitama Prefecture, Japan.
Modified from the I: 25,000 "Higashi-Matsuyama"
topographical map issued by the Geographical Survey Institute of Japan.

in occurred in the Godo Conglomerate. We
follow the stratigraphic nomenclature of
Koike et al. (1985) because of their intensive
geological study of the Iwadono Hills.
However, other names and combinations
have been applied by others who have investigated the area. One scheme is that ofMatsumaru and Hayashi (1980) who consider
the Kamagata Formation equivalent to theGodo Conglomerate. Majima (1989)
lumped the Godo Conglomerate and Negishi
Sandstone as the Goudo [=Godo] Formation.
The fossil site is located on land owned by
the Nihon Cement Co., Ltd. managed by the975.

Desmostylians from the Miocene Tokigawa Group

Chichibu Mining Co., Ltd. The mining
company has removed the massive tuffaceous
siltstone beds of the Shogunzawa Siltstone
and part of the underlying Negishi Sandstone.
Table 1.

Specimen Species

KZDOI

PJ.

KZD03
KZD04

KZDOS

KZD06

P.l.
PJ.
P.sp.

This removal has enabled fossil collectors toreach the Godo Conglomerate. An approximate area of 16 m X 60 m has been quarried in
the Godo Conglomerate, to a maximum

Supplemental information on desmostylian fossils from Kuzubukuro.
Tooth

Measurement

Identification(mm)

Left upper

M2

KZD02

Right upper
M2
Fragment of aM2orM3

m-d

b-I

c.h.

26.4 21.6

9.S+

m-d b-I c.h.
27.6 22.2 13.9
A-B
20.7~

Number of

S

?

mod

?
?

?
10
?

11,1981

Kazuhiko

January
8,1984

Obbe,

Isamu

February
1984

Honna,

Shin-ichi

March
1986

Shinkawa,

July 21.
1986

Shinkawa,

Saloro***Saloro*"

c.h.
10.6

2

0

0

100

November Shinkawa,
1986
Saloru·"mod b-I
25.0 20.4

c.h.
11.3

4

1

3

SO

November
16, 1986

Yabe,
Hideo

e-i
o-r
1+
9.5+ 14.5-+

?

?

30

January
IS, 1988

Takeda,Column ofa cheek tooth

13.~

Right upper
caninem-d b-Io-r
19.9+ 17.~ 31.4+

1

A-B

KZDlO

P.l.?

Left lowerM3

m-d b-l c.h.**32.9 22.0 IS.5

6

KZDll

P.l.

Left upper
caninemod b-Io-r
13.4+ 11.8-+ 18.2-+

1

P.l.

2+

SO

OdOIber

b-l
9.0

P.sp.

D.sp.

2

?

lis

KZD08

P.l.?

3

Right lower
P3
Right upper
Ml?

KZD13

?

D.sp. Fragmentary column A-B e-io-r 1+
ofamolar
24.2~
IS.4-+ 9.8+

P.l.?

KZD12

4

?

KZD07

KZD09

3

S

e-i
o-r 1+lU).+ 16.()'+

Fragmentary column A-B e-i
of a cheek: tooth
12.H 6.1

lDeplh IDiscovered piscovere:r;
Dare ~epository

jcusps jac.c. tub. (em)*o-r 1+
14.4-1

P.sp.

555

Column of a left
lower molar

m-d

b-l
o-r 1+
18.~ 18.8-+ 49.0-+
mod

1\1\
0

1

11\1\
?

?

March 12,
1988

Isamu

SO

April 10,1988

Yoshioka,
Keisuke?

August 7,
1988

Hideo

December
28,1988

Shin-ichi

April?
1989

Nakamwa,
Toyold?

30

Partial rightupper M2

c.h.
9.1

2+

2+

?

30

IS.3~ 22.2"

2

3+

?

\ 1\

180

b-l

KZD14

P.l.?

Right upper
M3

mod b-l c.h.
27.3 ~4.3+ 14.0

4

KZD1S

D.?

Milk carone.
.?

mod
7.9+

1

A-B o-r
8.1 16.4

Shoji
Obbe,

Yabe,

Ohtsu,

September Ohtsu,
28, 1989 Shin-ichi
MayS,
1990

• The values represent the depth from the Godo Conglomerate·Negishi Sandstone contact.
•• The height of the crown is measured on the buccal side of the column in the second row .
••• Satoru Shinkawa passed away in late February of 1992.

Fujii,
Koji

556

Kenshu Shimada and Norihisa lnuzuka

depth of 2 m. The contact between the
Godo Conglomerate and the Negishi Sandstone at Kuzubukuro varies from gradational
to sharp. The Godo Conglomerate dips
between 7 and IO degrees to the southwest at
the site. The member consists of many conglomeratic and sandy-conglomeratic layersthat are occasionally bedded. Some smallscale faults are evident, but no detailed lithologic or structural study of the unit has been
conducted at Kuzubukuro. The Godo Conglomerate contains well-rounded pebbles of
felsic tuff, that range up to 15 cm in diameter,and pebbles of crystalline schist, quartz diorite, gneiss, and hornfels (Koike et al., 1985)
that generally range from I to 5 cm in sizewith a wide range in roundness. Koike etal. (1985) stated that the Godo Conglomerate
had source areas from the west and north,based on the lithology of the clasts. The
desmostylian teeth were recovered directlyfrom the conglomerate at levels ranging fromabout IO cm below the top to as deep as 180
cm (Table I and Figure 2).
The geologic age of the units in the
Iwadono Hills is generally determined bybiostratigraphic studies of invertebrate fossils.
Koike et al. (1985) considered the age of the
Iwadono Formation as Middle Miocene,
although Matsumaru and Hayashi (1980)
gave a range from late Early to late Middle
Miocene. Matsumaru et al (1982) statedthat their Kamagata Formation should beplaced in the lowest part of Blow's N9 planktonic foraminiferal zone. Majima (1989)
considered his Goudo Formation to be late
Early to the earliest Middle Miocene. Koike
et al. (1985) stated that the Godo Conglomerate and the lower part of the Shogunzawa
Siltstone seems to correspond to Blow's zones
N9-NI3.
The most common fossils in the Godo
Conglomerate are shark teeth. Teleosteanteeth and mammalian fossils, including teeth
and ear bones of cetaceans and teeth of pinnipeds and desmostylians, have also beenfound. Kohno and Hasegawa (1991) recent-Iy described a tooth of an imagotariine pinniped that was found from the basal part ofMajima's Goudo Formation near Kuzubukuro. The Godo Conglomerate also contains some foraminifers, but other invertebrates are extremely rare. Most of the fossils
are strongly abraded, and the roots of theteeth are generally not preserved, which indicates a high depositional energy.

Materials and methods
A.

Materials

Fifteen desmostylian teeth are describedherein. Twelve specimens are considered to
be Paleoparadoxia and three Desmostylus.
The specimens are numbered as KZDOI,KZD02, KZD03, and so on, with KZ representing Kuzubukuro, 0 the Desmostylia,
and the number the chronological order of
discovery. Table I lists supplemental information on all the teeth.
B. Methods

The neotype of Paleoparadoxia tabatai(Tokunaga) was used to determine the species
and the tooth class of the samples. The
neotype is a nearly complete skeleton foundin the Miocene Yamanouchi Formation at
Inkyoyama, lzumi-machi, Toki City, Gifu
Prefecture. It is often referred to as the Izumi
specimen and is housed in the National Science Museum, Tokyo, Japan. The skull andits dentition were studied by Ijiri and Kamei(1961). Clark (1991) recently described a
new species, P. weltoni, that was discoveredfrom California; however, we think thatnone of the Kuzubukuro specimens belong to
P. weltoni as discussed later. Measurementsof six paleoparadoxian cheek teeth fromKuzubukuro are compared with described
specimens from other localities in Tables 2, 3,
and 4.
Inuzuka (1986) proposed the dental formula of Paleoparadoxia as 3/3, 1/1,3/3,3/3
in which both upper and lower Pis are notpresent. We follow the convention estab-

975.

lower

Desmostylians from the Miocene Tokigawa Group

Ileftlupper

premolarmolar

Figure 3. Schematic diagram showing the cusp
arrangements of paleoparadoxian cheek teeth in left
upper and lower premolars and molars (after Inuzuka, 1987). P, protocone or protoconid; M,
metacone or metaconid; Pa, paracone; A, anteriortalon; H, hypocone or hypoconid; E, entoconid;Y, posterior talonid. An open circle without
identification of cusp represents the generalized position of an accessory cusp. Solid black circles represent generalized positions of tubercles.

lished by Inuzuka (1987) for cusp designations and other purposes to describe paleoparadoxian teeth (Fig. 3). For some specimens(KZD03, KZD04, KZD05, KZD08, and
KZD 15) in which the tooth class is notsecurely determined, directional properties ofteeth are used.
We describe the specimens in detail,because: 1) only limited information ondesmostylian teeth has been published; and2) each of the specimens described here has
unique features. Because many paleoparadoxian cheek teeth are described herein,some general identification keys which weused should be noted. Reinhart (1959, p.
102) reported the characters of the cheek teethof Paleoparadoxia as: having a wide cingulum, that is heavily tuberculated with vertical ridges, completely encircling the cheekteeth that reaches approximately two-thirds
up side of crown; cheek teeth of closely
appressed cylindrical columns; distinct tendency toward polydonty; a central nipple-

557

like protuberance of enamel moat on theocclusal surface of unworn cheek teeth, withthe moat being surrounded by an upraisedring of enamel; and the primary cusps ofunworn teeth being higher and of greater
diameter than other columns. In order tocontrast the cheek teeth of Paleoparadoxia
from Desmostylus, he described the cheekteeth of Desmostylus as hypsodont.
Reinhart (1959, p. 102) also stated that the
paleoparadoxian cheek teeth consist of threetransverse rows, two columns per row, but theobservation was based only on two specimensof MaS. Mitchell and Repenning (1963)
generalized the paleoparadoxian cheek teeth
by stating that the columns "mayor may not
be appressed, polygonal or circular in crosssection, cingulum may be present and may
surround entire tooth, enamel base swollen,
column height forms about half of crownheight." We do not use their character,"enamel base swollen," due to its ambiguity.
Different authors use different criteria to
distinguish the tooth features. We definesome of the terms below to reduce ambiguities in such criteria.
Cusp: part of crown that forms a
polygonal or circular column regardless ofheight and has a small conical projection on
its occlusal surface if unworn or an enamel
opening if worn.
Accessory cusp: part of crown that forms
an incomplete column or rudimentary cusp
and has a projection, depression, or enamel
opening on its occlusal surface.
Tubercle: part of crown that forms anincomplete column or rudimentary cusp, withno projection, depression, or enamel opening
on its occlusal surface.
Cingulum: an enlargement of enamel onlateral surface of crown.
As Inuzuka and Murai (1980) noted, all ofthese features are transitional, and often noclear-cut distinction can be made. Thus, weoccasionally use some transitional terms, suchas tuberclelike accessory cusp and tuberculated cingulum. In addition, we distinguishKenshu Shimada and Norihisa Inuzuka

558

between the cervical line and crown base,wherein the former represents an original line,
and the latter describes the basalmost part ofenamel that shows any kind of damage.

\

m

5

C. Abbreviations

The following abbreviations are used in thetables: P. t. = Paleoparadoxia tabatai;
P.t.?=Paleoparadoxia ? tabatai; P.w.=
Paleoparadoxia weltoni; P. = Paleoparadoxia; D. = Desmostylus ; m-d = mesiodistal
diameter; b-l = buccolingual diameter; AB = A-B direction; e-i = exterior-interior
direction; o-r= vertical direction; c.h. =crown height (on the buccal side); ac.c. =accessory cusps; tub. = tubercles ; UCMP=
University of California, Museum ofPaleontology; LACM = Natural History
Museum of Los Angeles County.
The following abbreviations are used in the
figures: m = mesial side; d = distal side; b =buccal side; I = lingual side; e = exterior
side; i=interior side; A=side A; B=side
B; pr=protocone; me=metacone; hy=
hypocone; pa=paracone; ant. ta=anterior talon; prd = protoconid; med =metaconid; hyd = hypoconid; end =entoconid; post. tad = posterior talonid.
Systematic paleontology
Domning et al. (1986) and Clark (1991)
discussed the problems with the family-leveltaxonomy of the Desmostylia. However, we
use the traditional systematics in this paper,
because the taxonomy is not our main focus.
Class Mammalia Linnaeus, 1758
Order Desmostylia Reinhart, 1953
Family Paleoparadoxidae Reinhart, 1959
Genus Paleoparadoxia Reinhart, 1959
Paleoparadoxia tahatai (Tokunaga, 1939)

Specimen.-KZDII (Figs. 4, 19-2).
Diagnosis.-KZDII is half of the crown ofan upper canine. The identification is basedon the morphological resemblance between

6

b

7

d

-

o

1cm

Figure 4. KZDII: left upper canine of
Paleoparadoxia tabatai. I, occlusal surface; 2,basal surface; 3, mesial surface; 4, distal surface; 5,buccal surface; 6, lingual surface; 7, cross-sectionalviews taken at the position of x, y, and z in 5.

the specimen and the upper canines of the
Izumi specimen, particularly the presence ofthe peculiar crestal pit on the occlusal end of
the more or less conical-shaped crown. The
side determination is based on the crosssectional shape of the crown. Because thecanine is appressed against the maxilla in the
Izumi specimen, the lingual side is flatter thanthe buccal. Therefore, KZD II is a left upper
canine of P. tabatai with the basal half of thecrown not preserved.
Description.- The cross sections of KZD II
demonstrate that the rounded mesial anddistal margins near the occlusal end of thecrown become distinctive toward the basal
end. The crestal pit (0.7 mm in diameter and
0.4 mm in depth) is present near the center ofthe smooth occlusal end of the crown. Allother enamel surfaces exhibit a rough texture
consisting of many short, shallow grooves,parallel to the long axis of the tooth. A few
pits the size of a needle point are distributed
throughout the buccal enamel surface. In
the buccal and lingual views, the mesial
margin gently curves outward, and the distal
margin makes a rounded corner near the crestof the crown and extends nearly straight
toward the basal end. In mesial and distal

975.

Desmostylians from the Miocene Tokigawa Group

views, both buccal and lingual sides arealmost symmetrical, pinching in towards the
middle. The enamel at the crown base is 0.7
to 1.0 mm in thickness. The dentine has
been rounded due to depositional processes.
The pulp cavity is not seen on the dentine
surface.

Specimen.-KZDOI (Figures 5, 21-2).
Diagnosis.-KZDOI preserves a nearlycomplete, unworn{?) crown with no rootsystem. The M2 and M3 of the Izumi specimen have a diagnostically enlarged
protocone; however, the M2 and M3 can be
distinguished, because the M2 has a more
distorted oval outline than the M3 in occlusal
view. The location of the protocone,arrangement of other major cusps and tubercles (Figure 3) as well as the shape of thecrown in occlusal view indicate that KZDOI
is a left M2. The close resemblance with the
Izumi specimen suggests that KZDOI is P.

tabatai.
Description.- The buccal surface has atuberculated cingulum, whereas the other lateral surfaces of the crown are smooth andslightly swollen. In occlusal view, the tooth
is a distorted oval formed by the rounded
lingual and relatively straight buccal sides
with a mesiobuccal corner. The protocone is
9.4 mm in height and strongly tilts toward the
buccal side. The circular occlusal surface ofthe protocone, which strongly slants buccally,is 7 mm in diameter, and has a rough surface
and a slight central rise with an ambiguous
ant.ta mm

559

crestal pit. Accessory cusps exist at themesial and distal base of the protocone. The
mesial one (i.e., the lingual anterior talon)
has an oval depression on the top; whereas
the distal one has a rounded surface with asmall crestal pit. The distal end of the intermediate anterior talon fits against the
protocone, forming a crescent-shaped outline.
The buccal anterior talon is a tubercle, andthe paracone is an accessory cusp with acircular depression. The metacone,
hypocone, and a distal cusp (probably awell-developed posterior talon), are closely
gathered. All three cusps and the intermediate anterior talon range from 6 to 7 mm indiameter and have a nipplelike rise with acrestal pit at their centers. The rise is especially prominent on the metacone. Tubercles alternate with the paracone, metacone,and distal cusp along the buccal side.
Because the enamel is partially weathered,evidence of attrition is uncertain. The thickness of the enamel at the crown base ranges
from I to 2 mm, and it appears to be broken,
perhaps due to depositional processes.
Dentine is exposed on the basal surface withsome depressions corresponding to the positions of the major cusps on the occlusal side.
Enamel is exposed near the center of the basal
surface representing the contact between
protocone, paracone, metacone, andhypocone.

Specimen.-KZD02 (Figures 6, 21-3).
Diagnosis.-KZD02 preserves a worncrown with a partial root. It is a right M2 of
P. tabatai, identified in the same way as
KZDOL

d

d

-

o

2
1cm

Figure 5. KZDOI: left M2 of Paleoparadoxia
tabatai. I, occlusal surface; 2, basal surface.

Description.- The oval-shaped crown has alightly protruding mesiobuccal edge in occlusal view. A depression exists at the centerof the flatly worn tooth, where the protocone,intermediate anterior talon, paracone, andmetacone meet. From this meeting point,
the diameter of the protocone is about 10 mm,
and that of the intermediate anterior talon
and paracone about 8.5 mm. The lingualKenshu Shimada and Norihisa Inuzuka

560
m

m

b

d

2

o

1cm

-

Figure 6. KZD02: right M2 of Paleoparadoxia tabatai. I, occlusal surface; 2, basal surface.
White spaces represent damaged surfaces and portions still covered by sediments and fresh breaks.

anterior talon is a small accessory cusp andthe buccal anterior talon is a large accessory
cusp; both have dentine exposed at theircenters. A small accessory cusp is wedged
between the paracone and metacone on the
buccal side. The metacone and hypocone
are about 6.5 mm in buccolingual diameter.
All cusps have a circular or oval exposure ofdentine. An unworn, fan-shaped accessory
cusp, probably the posterior talon, exists atthe slightly swollen distal most edge of thecrown, and it has a conical protuberance witha small crestal pit. A large, flat, worn tubercle sits on the buccodistal corner, and a small
worn tubercle is located on the lingual side
between the protocone and hypocone. Eachmajor dentine exposure on the occlusal surface shows a faint, flat rise at the center. The
width of the enamel surrounding these
dentine exposures ranges from 1.9 to 3.3 mm.
The crown has a straight mesial side and aswollen distal side in buccal and lingual
views. The lingual crown surface shows agently swollen, wide, smooth cingulum with asmall fossa in the middle of the mesial side.
Many short, faint grooves run vertically on
the basal half of the crown, and the crownforms a tuberculated cingulum on the buccal
and distal sides. The cervical line at thecenter of the crown is horizontal but slopes
occlusally at the mesial and basally at the
distal ends. A smooth, incomplete root
stretches basally. The cervical line outlines arough square on the basal surface. The incomplete root is smoothly rounded because ofabrasion during deposition. The internalroot structure is unobservable due to theadhered sediments, but it seems to be single
rooted.

Specimen.-KZDI3 (Figures 7,21-4).
Diagnosis.-KZDI3 is a distal half of ahighly worn crown with no root. Because of
the way in which the mesial end of KZD13 isbroken, it appears that a large protocone wasoriginally appressed on the mesial side, withperhaps one or more smaller cusps at its side.
Assuming that the large missing cusp is a
protocone, KZD 13 is identified as a partial
right M2 of P. tabatai.
Description.-Although the mesial half ismissing, the buccal side of the specimen,
which forms a cingulum, is slightly better
preserved than the lingual side. A tuberclelike accessory cusp is located at the mesiobuccal corner and exhibits a shallow, faintdepression. A cingulum occupies the buccodistal corner of the crown. The metacone
looks like a distorted pentagon and is about
7.5 mm in both mesiodistal and buccolingual
diameters. The hypocone forms a trapezoid
about 8.0 mm in mesiodistal diameter and 7.0
mm in buccolingual diameter. Both themetacone and hypocone have a distorted
circular patch of dentine exposed at the center. An accessory cusp contacts the distalside of both cusps. The mesiodistal and........ _-_~__

ant. fa,/ r7l.
~'/ -.-<1.
: //\pa \ .............h .... ,
/'

b

\
,!

':

pr

:

II

1'-

:

'-""'--_....... ,

b

hy

d

1

d

-

o

2
1cm

Figure 7. KZD 13: partial right M2 ofPaleoparadoxia tabatai. I, occlusal surface; 2,basal surface.

975.

Desmostylians from the Miocene Tokigawa Group

buccolingual diameters of the accessory cusp
are about 6 mm and 10 mm, respectively.
This accessory cusp seems to be composed of
two fused accessory cusps as two small oval
enamel openings exist side by side. The
broken mesial surface reveals the internal
tooth structure of both enamel and dentine inwhich the basalmost part of the enamel curves
in an occlusal direction capping the dentine
at the hypocone, metacone, and tuberclelike
accessory cusp. The attritional surface
declines buccally. A short, lingually declined fissure on the distal surface shows theinclination of the hypocone. The distalcrown surface is partly coarse in texture, anda faint groove runs relatively horizontallynear the cervical line. Enamel about I mm
thick surrounds the dentine on the basal
surface, except on the broken mesial side.
Whether the cervical line has been damaged is
not clear. The dentine is apparently polished through depositional processes. A
large and a small depression, perhaps pulp
cavities, are seen on the dentine surface.

561

-

o

1cm

Figure 8. KZD03: fragment of a M2 or M3 of
Paleoparadoxia tabatai. I, occlusal surface; 2,basal surface; 3, interior surface; 4, exterior surface; 5, side A ; 6, side B. White spaces represent
portions still covered by sediments and fresh breaks.

Specimen.-KZD03 (Figure 8).
Diagnosis.-KZD03 is probably a part ofeither an upper or lower second or third
molar of P. tabatai when compared to thesize of the Izumi molars. The weak cingul urn suggests that this specimen may represent the lingual side of a molar, as this tendency is observed in the cheek teeth of the

m

m

b

d

1

d

2

m

3

-000
d

7

~cm

Figure 9. KZD09: right upper canine of Paleoparadoxia ?tabatai. I, occlusal surface; 2, basal
surface; 3, mesial surface; 4, distal surface; 5, buccal surface; 6, lingual surface; 7, cross-sectional views
taken at the position of x, y, and z in 5.

562

Kenshu Shimada and Norihisa Inuzuka

Izumi specimen. The declination, relative
size, and the arrangement of the cusps indicate that the columnar cusp may be thehypocone of a right upper molar. However,
because the columnar cusp is relatively large
in height and diameter, it may be theprotocone of a left upper molar. Therefore,
KZD03 is identified as a fragment of a M2 or
M3 of P. tabatai.
Description.-KZD03 consists of an unworn cusp, a large tubercle, and a small tubercle.
A small nipplelike conical protuberance witha crestal pit exists at the center of a rough,circular occlusal surface on the cusp. The
cusp is about 7.5 to 8.0 mm in diameter.
Paleoparadoxia ?tabatai

Specimen.-KZD09 (Figures 9, 19-1).
Diagnosis.-KZD09 is half of the crown ofan upper canine, because it more or lessresembles the upper canines of the Izumi
specimen and KZDII, and has the crestal pit.
Although KZD09 is much larger than the
Izumi upper canine and KZDII, it is not an
incisor, because incisors tend to have a fiat,
shovellike crown. The size difference
between the two specimens may represent
sexual dimorphism. KZD09 and KZD 11
preserve about the same portion of the canine,
but KZD09 is 75 to 80 percent larger thanKZDII. A similar ratio was obtained byHirota (1981) in his study of mandibles of P.
tabatai. He explained the size differences as
sexual dimorphism, with the larger form
being male. We tentatively assign KZD09 as
P. ?tabatai, because the identification israther tenuous. The cross-sectional shape ofthe crown suggests that the tooth is a rightupper canine.
Description.- The cross sections of KZD09
suggest that the buccal side curves more thanthe lingual side as the basal end is approached. A smooth, round area surrounds thecrestal pit. The pit is 0.3 mm in diameter.
The distal margin is somewhat sharper thanthe mesial margin. The mesial margin forms

a gentle arc, whereas the distal margin israther straight when viewed in the buccolingual direction. The lateral enamel surfaces
exhibit many faint ridges and grooves that areparallel to the long axis of the tooth. Twovery shallow and wide depressions trend in amesiodistal direction on the lingual surface.
The dentine is rounded due to abrasion during deposition, and no pulp cavity is seen.
The thickness of the enamel at the crown baseis about 0.7 mm at the buccal and lingualsides, and 1.0 mm and 1.2 mm at the mesial
and distal margins, respectively.

Specimen.-KZD07 (Figures 10, 21-1)
Diagnosis.-KZD07 is a nearly complete,moderately worn right MI? identified as P.
?tabatai. However, as both MiS in the
Izumi specimen are badly worn and no morphological description of an MI has beenpresented, our identification is made by theprocess of elimination. KZD07 cannot be a
premolar because of its much larger crown
SIZe. It is a little small to be a M2 or M3
although the outline of the crown and cusp
arrangement in KZD07 closely resembles theright M2 and M3 of the Izumi specimen.
However, KZD07 has a simpler occlusal
pattern than the M2 but is more complex than
p4 in the Izumi specimen. In addition,
KZD07 could not fit into the alveolar space
for the MI in the Izumi specimen but could fit
reasonably into the space of the MI. However, uncertainty remains in the taxonomic

m

b

d

-

o

2
1cm

Figure 10. KZD07: right Ml? of Paleoparadoxia ?tabatai. I, occlusal surface; 2, basal surface.

975.

Desmostylians from the Miocene Tokigawa Groupand dental assignments. We also note that asketch of a cheek tooth (UCMP 45274)
identified as Paleoparadoxia sp. by Mitchelland Repenning (1963) appears to be similar
to KZD07 in size, shape, and arrangement ofcusps. Thus, UCMP 45274 may be a rightMl as well.
Description.-In occlusal view, the tooth
has an oval outline in which the mesiobuccal
corner protrudes. The columnar protocone
is about 9.0 mm in height and 9.0 mm indiameter. The protocone strongly tilts buccally, and its attrition surface slants buccally.
The anterior talon is a triangular accessory
cusp, and the paracone is a distored oval
cusp. Their buccolingual diameters measured on the attrition surface are 3.1 mm and7.4 mm, respectively. Their mesiodistal
diameters, however, are unmeasurable due tothe lack of clear mesial margins. The
mesiobuccal and buccal sides of the paracone
and the mesial side of the anterior talon
exhibit a roughly textured, depressed area on
the enamel surface. The metacone andhypocone are about 7.5 mm in diameter. All
cusps and the anterior talon have an ovalshaped dentine exposure at their centers.
There is one tubercle mesial and two tubercles distal to the metacone. The enamel atthe crown base is 1.2 mm in thickness. The
root shortly extends basally, and a pulp cavity
is present. Four depressions that appear tocorrespond to the positions of the major
anUa

m

m

b

d

d

-

o

2
1cm

KZOI4: right M3 of Paleoparadoxia ?tabatai. I, occlusal surface; 2, basal surface. White spaces represent portions with fresh
breaks.
Figure 11.

563

cusps on the occlusal side are observed within
the pulp cavity.

Specimen.-KZDI4 (Figures 11,22-1).
Diagnosis.- The cingula on the Izumi
molars are generally well developed on the
buccal side. There is a greater developmentof the cingulum on one side of KZDI4;
therefore, we consider this side to be buccal.
KZDI4 is a right upper molar based on similar lengths of the mesiodistal and buccolingual diameters of the crown and its cusp
arrangement (Figure 3). Comparison of thecrown size of KZDI4 with the right upper
molars of the Izumi specimen suggests that
KZD14 is either a right M2 or M3, and is more
likely to be the latter because of its lessdistorted oval outline in occlusal view.
However, since the Izumi M3 S exhibit muchtaller cusps and less development of the cingulum, KZDI4 is considered to be a right M3of P. ?tabatai.
Description.- The dome-shaped crown consists of four major and two accessory cusps
surrounded by a highly developed cingulum.
All the tops of the major and accessory cusps
are at an equal elevation. Each major andaccessory cusp has a conical protuberance,with some exhibiting a crestal pit. The occlusal surfaces of all major and accessory
cusps decline toward the center of the crown,
forming a gap between them. A conicalprotuberance with a crestal pit is seen in thegap. The intermediate anterior talon,
protocone, metacone, and hypocone have acircular to oval occlusal surface that ranges
from about 5 to 6 mm in diameter. All cusps
have rounded sides, except for the intermediate anterior talon, which has a flat side. The
paracone is appressed to the buccal side of theintermediate anterior talon, giving the paracone a semicircular occlusal surface. The
lingual anterior talon is appressed to the
lingual side of the intermediate anterior talon
and the mesial side of the protocone. The
buccal anterior talon is not present. The
cingulum rises between the base of the par-

Kenshu Shimada and Norihisa Inuzuka

564

acone and metacone, the metacone andhypocone, and the lingual anterior talon andprotocone, forming tubercles. The height ofthe cingulum on the mesial edge is about 8
mm and gradually increases to about II mm
toward the distal side. Many faint verticalgrooves exist on the surface of the cingulum,and several shallow horizontal grooves occur
on the basal half of the cingulum. A shallow fossa exists in the middle of the cingulum
basal to the metacone. The middle portionof the lingual surface of the cingulum isdepressed. The cingulum directly basal tothe intermediate anterior talon has dentine
exposed, perhaps representing the mesial
facette. The enamel is 0.5 to 1.0 mm thick on
the basal surface. The lingual half of thedentine shows a smooth flat surface indicating
destruction during deposition, whereas the
buccal half exhibits a rough, fresh fracture ofdentine damaged at the time of removal fromthe deposit. The tooth is considered to be
single rooted because of a faint circular structure on the dentine surface.

Specimen.-KZDIO (Figures 12, 22-2).
Diagnosis.-KZDIO consists of a wellworn crown of a molar with no root.
KZD 10 shows the cusp arrangement of thelower molar (Figure 3), which is six appressed
cusps arranged in two columns of three trans-

m

m

prd

b

b

post.
tad

d

-

o

1cm

Figure 12. KZD 10: left Ma of Paleoparadoxia?tabatai. I, ocd usal surface; 2, basal surface.
White spaces represent portions still covered by sediments.

verse rows. This arrangement of cusps isseen in the Mgs of the Izumi specimen, as wellas in the Moniwa specimen identified as a left
Mg of P. tabatai (Inuzuka and Murai, 1980).
Because KZDIO lacks a distinct cingulum,
which is found in the Izumi and Moniwa
specimens, it is reported here as P. ?tabatai.
Ijiri and Kamei (1961) noted that the lower
cheek teeth in P. tabatai tended to be moreworn at the buccal and distal sides relative tothe mesial and lingual sides. KZD 10 is thus
identified as a left Mg of P. ?tabatai.
Description.- The tooth, which is slightly
swollen laterally, is in the shape of a stretchedoval in occlusal view. The six cusps and thetubercle on the distal edge exhibit a smooth
attrition surface that slants buccodistally. In
the first row, the protoconid and metaconid
are joined, and the dentine of these cusps is
exposed as combined distorted ovals. The
rounded peak of the metaconid is seen as thehighest point of the tooth. The squarehypoconid differs from the entoconid andposterior talonids in that it has the largest
attrition surface and dentine exposed. The
entoconid and two posterior talonids haveabout equal areas of attrition surface andhave a circle of dentine exposed in theircenters. The attrition surface of the first andsecond rows have the same dimension in a
buccolingual direction, measuring 15.2 mm,
and the third row is slightly narrower,
measuring 13.8 mm. The second and thirdrows have the same dimension on the attrition
surface in a mesiodistal direction, measuring
about 8 mm, whereas the first row is about II
mm. Many short, shallow vertical and inclined grooves are distributed on the lower
part of the crown forming a rough surface.
A shallow, transverse depression runs
through the rough basal half of the crown on
the distal surface. The enamel along thecervical line is I mm thick. The cervical line
corresponds to the outline of the tooth, except
near the middle where it narrows in a buccolingual direction.

975.

Desmostylians from the Miocene Tokigawa Group

m

I

m

~~
"

b

, .' ," h d
d

Y

b

1

d

-

o

2
1cm

Figure 13. KZD06: right P3 of Paleoparadoxia sp. I, occlusal surface; 2, basal surface.

Paleoparadoxia sp.

Specimen.-KZD06 (Figures 13, 20).
Diagnosis.-KZD06 is a complete crown ofa right P3 of Paleoparadoxia that consists of
two complete cusps, protoconid andhypoconid, with a slight extension of a root.
This identification is based on a direct comparison with the Izumi specimen. Because
KZD06 has a greater mesiodistal diameter
than the buccolingual diameter, it probably isa lower cheek tooth. KZD06 cannot be theP4 or any lower molar as those in the Izumi
specimen are much larger in size and structurally more complex (i.e., having a larger number of cusps and accessory cusps); however,the characters of M j are speculative due to thepoor preservation of this tooth class in the
Izumi specimen. Both P2 s in the Izumi specimen have a conical main cusp with a distal
tubercle, and P3 s possess three columnar
cusps. The protoconid and hypoconid of
KZD06 resemble those of the right P 3 in the
Izumi specimen. The metaconid appears to
be undeveloped in KZD06. The crownheight of KZD06 is much lower than the
Izumi P3 , but this difference can be explainedby the degree of wear. The wear pattern of
the hypoconid also differs between the two
specimens. KZD06 has a weak buccallydeclining attrition surface in contrast to the
P 3 s in the Izumi specimen which exhibit avery steep, distally slanting surface. Because
KZD06 morphologically differs from theIzumi P 3 s in cusp number, wearing pattern,
and size, KZD06 is designated Paleoparadoxia sp.
Description.-In occlusal view, the oval-

565

shaped crown, which swells laterally, is slightly concave on its mesiolingual side. The
protoconid is located somewhat ligually andmeasures about 7 mm in a mesiodistal direction, and large amount of dentine is exposedon the attrition surface. The hypoconid,
with a mesiodistal diameter of 4.5 mm, comprises the distal 1/3 of the tooth and has asmall circle of dentine exposed at the center.
The highest point of the tooth is at the junction of the two cusps. The buccal surface ofthe crown is smoother than the lingual side.
A shallow groove, ranging between 0.4 and
0.9 mm in width, surrounds the entire crownrunning parallel to and about 2.5 mm aboveee

A~BB/:~A
V \,JJe ~,_(--~
1

i

i

trW! fj'\"A~,' B B"

\

I

',j 3

',:' C'

. 'I

','

".

~

~
-' 5
.~.;..

I'.,:e '::, ~~. I i i
:

2

.' e

6

-

o

A

4

p'.

...:'

',:

, J

1cm

Figure 14. KZD04: fragmentary column of acheek tooth of Paleoparadoxia sp, I, occlusal surface; 2, basal surface; 3, interior surface; 4, exterior
surface; 5, side A; 6, side B. White spaces represent damaged surfaces and portions still covered by
sediments.

a
.

e :

/~':"I",",.

i

i

5

B

3

4

-

o

6
1cm

Figure 15. KZD08: column of a cheek toothof Paleoparadoxia sp. I, occlusal surface; 2, basal
surface; 3, interior surface, 4, exterior surface; 5,side A; 6, side B, White spaces represent portions
still covered by sediments,

Kenshu Shimada and Norihisa Inuzuka

566

the cervica l line. The ename l at the cervicalline is about 0.3 mm thick. The short root ishighly rounded due to depositional processes.
No pulp cavity is recogni zed , but the tooth isthought to be single rooted.

1

2

5

Specimen. - KZD04 (Fig ure 14).
Diagnosis.-Estim ating the total size of thecusp, we surmise that KZD04 may be a fragmentary column of a cheek tooth of Paleoparadoxia; however, the exact species and toothclass is undetermined .
Description ..- KZD04 preserves a small
portion of a well-worn cusp . The maximum
thickness of the enamel , 2.3 mm , is seen on theocclusal surface.

Specimen.- KZD08 (F igure 15).
Diagnosis.-KZD08 is perhaps a column ofa cheek tooth of Paleoparadoxia , based on an
estimate of the total size of the cusp , but it is
too fragmentary to determine the exact species
an d tooth class.
Description. - KZD08 preserves a relatively
complete cusp with a slight extension ofenamel. The thickness of the enamel o n thebasal si de is 1.5 mm.

A

A

-

o

1cm

Figure 16. KZ005: fragmentary col umn of amolar of Desmosrylus sp. I, occl usal surface ; 2,basa l surface ; 3, interior surface; 4, exterior surface; 5, side A; 6, side B. White spaces represent
portions with fresh breaks.

Family Desmo sty lid ae Osborn , 1905
Genus Desmostylus Marsh, 1888
Desmostylus sp.

Specimen. - KZD05 (Figure 16).
Diagnosis .- KZD05 is 1/ 3 of a well-wornenamel column, and it is thought to be a
fragment of a mol a r of Desmostylus due to its

m

m

m

2

5

-

o

1cm

Figure 17. KZO 12 : co lumn of a left lower molar of Desmostylus sp. I, occlusa l surface; 2, basal
surface ; 3, mesial surface ; 4, di stal surface ; 5, buccal surface ; 6, lin gua l surface. White spaces represent
portions sti ll covered by sediments a nd fresh breaks.

975.

Desmostylians from the Miocene Tokigawa Groupsize. The hypsodont crown of KZD05 withno cingulum suggests that it belongs to Desmostylus. However, because the fossil is so
incomplete, the tooth orientation, tooth class,and species cannot be identified.
Description.- The preserved enamel has amaximum thickness of 7.3 mm. The exterior
surface exhibits very coarse texture. Sides A
and B on the interior surface show broken
surfaces apparently caused by depositional
processes. However, the broken surface ofside A is well polished and forms a smoothsurface; whereas, the broken surface of side B
shows an uneven surface, although it is also
polished. Numerous parallel enamel prismgroups (Vanderhoof, 1937), "Schreger's
stripes" (Ijiri, 1939; Reinhart, 1959; Kozawa, 1984), are visible on both broken surfaces but better exhibited on the surface ofside A.

567

m

m

AOB B
d

1

d

A A

d

3

-

o

7
1cm

Figure 18. KZDI5: milk canine? of Desmostylus? I, occlusal surface; 2, basal surface; 3,
mesial surface; 4, distal surface; 5, side A; 6, side
B; 7, cross-sectional views taken at the position of x,y, and z in 5.

two surfaces are thought to be the buccal anddistal sides in which the width of the flat
surface is wider on the former than the latter.
Desmostylus ?

Specimen.-KZDI2 (Figures 17,23).
Diagnosis.-KZDI2 is considered to be acolumn of a left lower molar of Desmostylusthat is characterized by its hypsodont crownwith no cingulum. As described below,
KZD 12 shows two different directions ofwear. It also shows two flat lateral sides,
which meet at approximately a right angle.
Because the columns in upper teeth do not
generally form at right angles, the specimen isperhaps a lower molar. Moreover, KZDI2 isidentified as a metaconid of a left lower molar
by considering its size and position (see Inuzuka, 1987, Figure 5). Hence, the wear
marks at the mesial and distal sides perhaps
represent the mesial facette and the attrition
surface, respectively. Its exact tooth classand species are however unknown.
Description.-KZDI2 shows two different
directions of wear at steep angles. Eachworn surface has an enamel opening close to
its center exposing the same mass of dentine
by penetrating the enamel from two different
directions. Two lateral sides are flat, meeting at about a right angle and indicating theattachment of unpreserved columns. These

Specimen.-KZDI5 (Figure 18).
Diagnosis .-KZD I 5 is tentatively
identified as an unworn milk canine? of
Desmostylus. The identification is based on
the presence of the crestal pit suggesting that
KZD I 5 is probably a desmostylian tooth.
The specimen is not P. tabatai, because it
does not have any significant ridge and is notcompressed in any direction; therefore, it
differs in morphology from any of the Izumi
teeth. KZD I 5 also differs from most teeth of
P. weltoni in morphology, except for the
lower canine that somewhat resembles it;
however, KZD I 5 differs significantly from P.
weltoni by its small size. By eliminating thepossibility of Paleoparadoxia, the alternative
taxonomic assignment that can be drawn
from our current knowledge is Desmostylus.
Because KZD I 5 is uniconical in shape, itcannot be the incisor of Desmostylus which ischaracterized by its unicolumnar shape (Hannibal, 1922; Inuzuka, 1988). The only
remaining possibility is the canine. Considering the sketch of the canine of D. hesperus given by Vanderhoof (1937) and the state-

568

Kenshu Shimada and Norihisa lnuzuka

2

lc

4

2c
Figure 19. Paleoparadoxian upper caninesfrom Kuzubukuro. I, right upper canine of
Pa/eoparadox ia ?rabatai (KZD09); 2, left upper
canine of Pa/eoparadoxia rabatai (KZDII). a,
occlusal view; b, di stal view ; c, lingual view.
Approximately natural size.

ment , " the size of the tusk varies with age,"presented by Reinhart (1959), we report
KZDl5 as a milk canine, although uncertainty still remains. Reinhart (1959) statedthat " the tusk " of Desmostylus is "oval incross section and slightly curved ," describing
the overall view, including both crown androot. The cross section of KZD IS is a nearlycomplete circle, and therefore theidentification of right or left cannot be determined . Whether the tooth is upper or lower
is also unknown .
Description. - The crestal pit is I mm indiameter and is situated slightly di stal of thecenter of the nearly complete circular outl in eof the tooth when viewed occlusally. Viewed from sides A and B, the outline of the
distal side is straight, whereas the mesial side
becomes convex at the occlusal 1/ 5 and basal
1/ 4 of the crown. The enamel surface issmooth through the tooth although someslight depress ions are present. In mesial anddi stal views, the overall outline is a symmetrical , acute-angled triangle with a rounded crestand slightly swollen sides near the base. The

Figure 20. Right P3 of Pa/eoparadox ia sp.
from Ku zubukuro (KZD06). I, occlusal view ; 2,basa l view ; 3, mesial view; 4, distal view; 5, buccal
view; 6, lingual view . Approximately nat ural size.

basal end of the crown on the distal side isrounded due to deposition a l processes. The
thickness of the enamel on the mesial side isabout 0.9 mm. The dentine fills in theenamel to a depth of 4.2 mm at the basal side.

Remarks and comparisonsA.

a.

Paleoparadoxia

Canines
Besides this paper, the work of Ijiri andK a mei (1961) is virtually the only report on
the upper canine morphology of Paleoparadoxia . Because KZ009 and KZO II consist of half of the crown and the information
is limited , a pertinent comparison with even
the Izumi specimen can be hardly approachedat this stage. Because the only specimen of
P. we/toni does not pro vide information
about the upper cani nes (Clark , 1991) , wecannot compare it with KZD09 and KZOIl.
However, potential sexual dimorphism in thesize of canines as discussed previously isworth noting.
b . Cheek teeth
Although a number of paleoparadoxiancheek teeth froin Japan have been reported , it

975.

Desmostylians from the Miocene Tokigawa Group

569

1b

1a

1c

3f

2b

4a

2c

2e

2d

2f

4c

4d

4e

4f

Figu re 21. Pa leoparadoxian Ml and M's from K uzubukuro . I, rig ht Ml? of Paleoparadoxia?tabatai (KZD07) ; 2, left M' of Paleoparadoxia tabatai (KZDO I); 3, right M' of Paleoparadoxia
tabatai (KZD02) ; 4, partia l righ t M' of Paleoparadoxia tabatai (KZD 13). a, occ lusa l view ; b, basal
view; c, mes ia l view; d , dista l view ; e, buccal view; f, li ngua l view.

Approx imate ly natura l size.

570

Kenshu Shimada and Norihisa Inuzuka

seems that information on tooth morphology
is still limited. Tokunaga (1939) reported
two desmostylian teeth from Sado Island, theSawane specimens, which are now considered
to belong to Paleoparadoxia. Unfortunately, these teeth were lost by fire during theSecond World War; however, another tooth,that was conceivably discovered at the sametime, was recently found but has not beenstudied in detail. In 1944, Takai reported
the Hannoura specimen that was determined
to be a left pa of D. japonicus, but it was later
re-identified as Paleoparadoxia (lnuzuka,
1984); however, the latter identification isstill questionable due to morphologicaldifferences between the specimen and theIzumi pas. A partial set of teeth with adentary, the Chichibu-Terao specimen, wasreported by Arai (1953); however, as thestudy of the Izumi specimen was still inprogress, the report was not able to be comprehensive. Although no specific morphologic trait of the molars of P. tabatai waspresented, cranial study of the Izumi specimen (ljiri and Kamei, 1961) made it possible
to compare measurements with other specimens. The Akibi specimen, a left P4 ? of P.
tabatai discovered in Toyama Prefecture, wasreported by Shikama (1966a). Kamei (1967)
reported a right PI of P. tabatai, the Tomikusa specimen, and microscopic study waslater conducted on this tooth by Kobayashi
and Kamei (1973). The Wainai specimen, aright Ma of P. tabatai, of uncertain provenance (as it was found in an archeological site in
Iwate Prefecture), was described by Inuzukain 1977. Fujimoto and Sakamoto (1978)
briefly reported the discovery of the
Chichibu-Ogano specimen, a skeleton of
Paleoparadoxia, along with pictures of a left
P4 ? and a right M2, but the study has notbeen completed. Tsunoda and Ogano Collaborative Research Group (1978) reported
the occurrence of aMI of P. tabatai from the
Chichibu basin. They described no morphology but presented a detailed study of thestratigraphic context. Inuzuka and Murai

Table 2.

Measurements of paleoparadoxian P3S.

Izumi(ljiri and UCMP 114285
KZD06(This repon) Kamei, 1961) (Clark,1991)
P.w.
P.t.
Species
P.sp.
Right
Left Right
Left 1 Right
Right/Left
15
16.5
12.5
Measure-J m-d
15 J 15
11 1 119.0
13
13
ment(mm)! b-l
Specimen

Table 3. Measurements
upper molars.

of paleoparadoxian---

Tooth Class

MI7

M2

M2

M3

Specimen

KZD07

KZD01

KZD02

KZDl4

(This report)

Measw-ement m·d b·1 m-d b·1 m·d b-I m·d b·1

Izumi (ljiri andP.I.

Kuzubukuro

Species

P.I.?

P.I.

P.I.

P.I.?

Specimen

Right/Left

Right

Left

Right

Right

(mm)

25.0 20.4 26.4 21.6 27.6 22. 27.3 24.3

Left

20 20 28.5 27 28.5 27

28

Kamei,1961)

Right

16+ 21

28

27

UCMP 114285 P.w.

Left

21- 17- 21- 17- 19

18(Clark, 1991)

Right

29 26.

29 26.

25• Approximate measurement of a damaged tooth.

(1980) reported a left Ma of P. tabatai, theMoniwa specimen, which was found in
Miyagi Prefecture. Recently, a right P 4 of P.
tabatai was described by Kaneko and Inuzuka (1992). It was discovered in Toyama
Prefecture and was named the Tsuzara specimen. Despite these reports, the morphologyof the cheek teeth in P. tabatai does not seemto be well established, except for the Ma dueto the study of this particular tooth class byReinhart (1959).
Technical reports on cheek teeth of
Paleoparadoxia are even rare in the UnitedStates. Reinhart (1959) reported two specimens of P. tabatai, UCMP 32076 and UCMP
40862. He described UCMP 32076 as either
a right upper or left lower cheek tooth (p. 96),
although he also described it as "(left lower)
cheek tooth" (p. 144). Recently, this specimen was assigned to a Ma by Clark (199 I) ;therefore, it is probably a left tooth. UCMP
40862 is a partial right dentary, and the only
preserved cheek tooth is identified as a right
Ma (Reinhart, 1959). Four cheek teeth of975.

Desmostylians from the Miocene Tokigawa Group
Table 4.

Specimen

KZDI0(This report)

Species

PJ.?

Right/Lefl

Left

Mouure'lm-cmenl(mm)1 bol

32.9
22.0

571

Measurements of paleoparadoxian Mas.

Izumi (ljiri ond
Wainai
Moniwa (Inuzuk. LACM4371a UCMP32076 UCMP40862 UCMP9S944 UCMP 114285
Klmei.I96I) (Inuzuk•• 1917) Uld Murai. 19S0) (Milchell.1963) (Clark. 1991) (Clark. 1991) (Clark. 1991) (Clark. 1991)
P.w.
P.op.
Pl.
P.I.
P.op.
P.I.
P ..p.
P.op.
Lefl RighI
Left
Lefl RighI
RighI
?
RiShl
Left
Left
23
23
34.5
34.S
24+
3S.2
32.5
34
34
17
17
25.S
25.5
25
22.5
2S.0
25.6
25
29

• Specimen originally described as P. tabatai by Reinhart (1959).
based on Reinhart (1959).

Paleoparadoxia. sp. were reported in papers
by Mitchell (1963) and Mitchell and Repenning (1963): a complete tooth (probably aleft Ms) (LACM 4371a), a premolar (LACM
4371 b), an incomplete tooth (UCMP 63981),
and a complete tooth (UCMP 45274).
Recently, Clark (1991) described a new
species, P. weltoni (UCMP 114285), that has awell-preserved dentition. He also presented
measurements of UCMP 95944, a Ms thatbelongs to P. sp. Besides the specimen of P.
weltoni, it seems that only UCMP 40862 hasbeen reliably identified by tooth class among
the specimens of paleoparadoxian cheek teeth
in the United States.
Tables 2, 3, and 4 show the measurementsof paleoparadoxian cheek teeth fromKuzubukuro compared to the other known
cheek teeth of the genus. Because the attrition phase varies from tooth to tooth, thecrown height of all teeth is not treated inthese tables. Table 2 shows that KZD06 as a
P s is much smaller than the corresponding
tooth class of the type specimen of P. tabatai
and P. weltoni. Therefore, KZD06 cannot
be readily classified into either species
although the small size is explained if it is amilk tooth. However, no conclusion can bemade only from this isolated tooth. An
easily recognized trend seen in Tables 3 and 4
is that the molars of P. weltoni are muchsmaller in size than the Kuzubukuro molars
although the MIS of the former are not preserved. Thus, the Kuzubukuro specimens are
not considered to belong to P. weltoni. The
measurements of MIS of the Izumi specimen
are presented by Ijiri and Kamei (1961);

The identification of right or left ishowever, the Izumi MIS are heavily wornpreserving only the very basal end of thecrown and partially exposed root with areduced attritional surface area, and are notrepresentative of the unworn teeth. It seems
that KZD07 is slightly smaller than the original unworn Izumi MIS in both mesiodistal
and buccolingual directions. If this is true,
then all the complete upper molars fromKuzubukuro are smaller in the mesiodistal
and buccolingual diameters than the Izumi
specimen. A similar result is also seen for
Ms in which KZD 10 is smaller than any otherreported paleoparadoxian Ms (with complete
measurements) except for UCMP 40862 (P.
sp.) and UCMP 114285 (P. weltoni). In
addition, it seems that the buccolingual direction of the complete Kuzubukuro molars are
generally proportionally smaller than the
Izumi specimen with respect to mesiodistal
direction. The presence or absence of cingula on Kuzubukuro molars does not appear
to have a bearing on their smaller size, but the
major cusps, accessory cusps, and tubercles in
the Kuzubukuro specimens are more closely
gathered than those in the Izumi specimen.
It is curious that Clark (1991) also encountered small size in the molariform teeth of P.
weltoni, suggesting it could represent either
an autapomorphy for P. weltoni or a retained
primitive condition. However, the reason
for the trend for small crowns in the Kuzubukuro teeth is unknown, because they are notin association with a skull.

Kenshu Shimada and Norihisa Inuzuka

572

2c

../
(
.

~
,

.'

','

~, t. 'I

I

.

' .

2d

Figure 22. Paleoparado xia n M3 and M3 from Kuzubukuro. I, right M3 o f Paleoparadoxia?tabatai (KZDI4) ; 2, left M3 of Paleoparadoxia ?Iabalai (KZDIO) . a, occlu sa l view; b, basa l view ; c,mesial view ; d , di sta l view ; e, buccal view ; f, lin gua l vie w.

B.

a.

Desmostylus

CanineAlthough Vanderhoof ( 1937) and Reinh a rt(1959) discu ssed the can ines of Desmostylus ,information a bout this tooth cl ass is st illlimited. Therefore, no comparison is madefor KZDIS .
b . Cheek teeth
The significance of KZDOS a nd KZD 12,
which are un a mbiguously identified as Desmostylus, lies in their co-occurrence with
Paleoparadoxia in a single bed in a limitedarea, a lthou gh the teeth m ay be reworked as
di sc ussed later. As Mitchell a nd Repenning(1963) considered the notes of Yabe (1959) ,the Izumi ske leton of P. tabatai (Ijiri a nd
Kamei , 1961; Shik a ma , 1966b) and the
Togari skull of D. japonicus (Yoshiwara a ndIw asaki , 1902; Tokunaga and Iwasaki , 1914)
are from two different localities a bout 3 km

Ap p rox im a tel y natural size.

apart butequivalentfrom roughly st ratigra phicall ybeds. The co-occurrence ofPaleoparadox ia (Iw aya specimen) and Desmosty lus (Nan ao spec imen) from the sa me
o utcrop in the sa me unit at the Noto Peninsula, central Jap a n was reported by Inu z uk a
( 1984), Kaseno (1984) , a nd Inu z uk a andKa rasawa (1986) , a lthough the desc ripti o ns of
the fo ss il s are st ill unpubli shed . Therefore,
this pape r is the seco nd report o n the coocc urrence of Paleoparadox ia and Desmosty lus fro m exactly of the sa me bed in the samea rea of Japan. H oweve r, no comparisons are
made for KZDOS and KZD 12, bec a use the ya re so fragmentary.

Discussion
A.

Geological aspects of the fossils

Ch i nze i (1984) di sc ussed the modes of975.

Desmostylians from the Miocene Tokigawa Group

Figure 23.

Co lumn of a left lower molar ofI,
mesial view ; 2, lingual view. Approximately natural size.

Desmostylus sp. from Ku zubukuro (KZDI2).

desmostylian occurrence and roughly divided
them into two categories: I) isolated teeth ,and 2) skeletal remains. He stated that ma ny
isolated teeth occur in high-energy deposits
such as coquinas and conglomerates, a nd thatthe majority of these teeth were reworked.
He noted that the occurrence of shark teeth
with isolated desmostylian teeth could be
explained in the same way due to the highresistibility and high fossili zatio n potential ofteeth. Although the fossils from the Godo
Conglomerate are generally rounded , we have
not yet found conclusive evidence that thedesmostylian s are derived from another horizon. No certain lithologic difference
between the enclosing sediments and the sediments still filling depressions and cavities on
the teeth has been found. However, wecannot dismiss the po ss ibility that the teeth
are reworked. The broken surfaces of sides
A and B of KZ005 are poli shed apparently
by depositional processes with distinctively
different degrees of polish on the two surfaces.
The broken surface of side A is very smooth ,whereas side B shows an uneven poli shedsurface. This difference can be interpreted as
representing two different depositional stages,
with si de A exhibiting an older break thanside B. Due to taphonomic problem s, thetaxon range zo ne of desmostylians cannot be

573

determined with accuracy as commented
upon by Chinzei (1984). Although depo sition of the lower ha lf of the Iwadono Formation probably took place sometime between
the late Early Miocene and middle Middle
Miocene (Matsumaru et al. , 1982; Koi ke etal ., 1985 ; Majima, 1989) , this does not necessa rily represent the true range of the desmostylians.
Accord i ng to Koi ke et al. (1985) , the Ii thology of the clasts in the Godo Conglomeratesuggests that the lands to the north and west
were the main so urces of supply. Interestingly, about 30 km west of Kuzubukuro is the
Chichibu Basin where several occurrences of
Paleoparadoxia are known (Arai , 1953 ; Fujimoto and Sakamoto, 1978 ; Tsunoda a nd
Ogano Collaborative Research Group , 1978 ;Sakamoto, 1983) . All of these fossils arecomplete or parti a l skeletons, reducing the
likelihood of reworking. Although most ofthem were found in horizon N9 foraminiferalzone (see Chinzei, 1984), the one discussed by
T sunoda and Ogano Collaborative ResearchGroup (1978) is the oldest known Paleoparadoxia in Japan , because it came from horizon N6 (Chinzei, 1984). Unfortunately,
becau se most of these fossils have not beenstudied well , we could not make any compariso n between the Kuz ubukuro and Chichibu
teeth. However, it would be interesting tocompare them in the future .
B.

Occurrence of sharks with Desmostylia

The significance of numerous shark teeth
found in the Godo Conglomerate should beconsidered. Because shark systematics are
not the focus herein , thus , we follow thenomenclature used in ltoigawa et al . (1985).
]n his report , Inuzuka (1984) showed that
desmo sty lians are known from 59 localities inJapan , and Goto a nd Kuga (1984) stated thatelasmobranchs have been found at 20 of themalong with marine mammals , such as pinniped s, sirenians, a nd cetaceans. Goto andKuga (1984) included Kuzubukuro as one ofthese 20 localities, but they were aware of

574

Kenshu Shimada and Norihisa Inuzuka

only Isurus hastalis (Agassiz). Itoigawa etal. (1985) reported that the most abundant
shark species from Kuzubukuro are
Odontaspis cuspidata Agassiz and Isurusdesori (Agassiz). This observation seems to
be correct, but some other important factors
should be added. Although I. desori is themost abundant species of the genus Isurus, I.
hastalis is also commonly found. We canconfirm the occurrence of I. planus (Agassiz)
at the site, first tentatively recognized by Itoigawa et al. (1985). The taxon range zone ofI. planus is the Middle to Late Miocene of thecircum-Pacific region, the United States(California) and Japan (Kuga, 1985; Itoigawa et al., 1985; Karasawa, 1989). Kuga
(1985) noted that the species occurred in the
Moniwa Formation in Miyagi Prefecture, theIwaya Calcareous Sandstone Bed in Ishikawa
Prefecture, and the Fujina Formation in
Shimane Prefecture, where isolated desmostylian bones and teeth are also known (Inuzuka, 1984). Although the data are still limited, there seems to be both stratigraphic andgeographic significance in their cooccurrence. Several other species of Isurusare recognized as well, and the whole genus
appears to be the predominant shark group at
Kuzubukuro. Based on the work of the
Kuzubukuro Geology Club, one of theauthors (Shimada) is convinced that at least
20 shark species, and perhaps as many as 25 to
30 species, are represented in the Godo Conglomerate Member, including Carcharodon
megalodon Agassiz, Isurus benedeni (LeHon), and Dalatias licha (Bonnaterre).
The Odontaspis-Isurus assemblage and theother shark species from Kuzubukuro appear
to be similar to the fossils from the Miocene
formations of the Noto Peninsula in central
Japan, as reported by Karasawa (1983, 1989).
The Miocene units of the Noto district are
known as one of the richest areas for desmostylians, including the Iwaya and Nanao specimens (Takai, 1944; Kaseno, 1964, 1984;
Shikama, 1966a; Inuzuka and Karasawa,1986). Kaseno (1984) noted that desmos-

tylian remains are found in shallow marine
strata of the early Middle Miocene (ca. 14-13
Ma). However, Chinzei (1984) indicated thepossibility of the desmostylian material fromthe Noto Peninsula being reworked, because
most specimens are found as isolated teeth orbone from coarse-grained deposits, althoughsome of the desmostylians from the Noto
Peninsula less likely to be reworked (Inuzuka
and Karasawa, 1986). Even if the fossils
from Kuzubukuro and Noto Peninsula areallochthonous, the fact that there are similarities in the vertebrate fauna from these two
distant areas is noteworthy.
Desmostylians in association with sharkfossils have been documented in the UnitedStates as well (e.g., Merriam, 1906; Anderson, 1911; Mitchell and Lipps, 1965; andZuidema, 1970). Vanderhoof (1937) pointed
out that the teeth of Carcharodon and Isurusconstantly occur with Desmostylus. Repenning and Packard (1990) recently discussed
the probable predation on Paleoparadoxia bysharks. They noted the nearly complete but
undescribed Stanford specimen discovered in
California and its association with 24 shark
teeth comprising many Isurus and some
Galeocerdo teeth.
Due to taphonomic considerations, it isdifficult to say whether the sharks and desmostylians of the Godo Conglomerate coexisted or are just co-occurring. It seems also
unlikely that the Kuzubukuro fossils will
yield evidence that would reveal their true
paleoecological relationship. However, as
Goto and Kuga (1984) stated, it is natural tothink that sharks and desmostylians coexisted
during the Miocene by their frequent associations in the fossil record. Moreover, as Kuga
(Inuzuka, 1984 ed.) mentioned, we believethat sharks were likely predators and scavengers on desmostylians during the Miocene.
Acknowledgment

We especially thank Dr. Tadao Kamei,
professor emeritus of Kyoto University who

975.

Desmostylians from the Miocene Tokigawa Group

provided this research opportunity. We
gratefully acknowledge Dr. Richard J. Zakrzewski, Fort Hays State University, for improving this paper; Dr. Michael E. Nelson,
formerly of Fort Hays State University, forallowing the use of university facilities; Dr.
Yukimitsu Tomida, National Science
Museum in Tokyo, for allowing access to the
Izumi specimen; and Isamu Baba, a secretaryof Kuzubukuro Geology Club, for supporting
the overall project. Mitsuko Koike of Oi
Senior High School and Kensaku Takei of
Kosei Gakuen Senior High School provided
very useful information about the geology of
Kuzubukuro. We are greatly indebted to allof the individuals who discovered the described fossils and provided access to them.
We also thank Gregory A. Liggett, Cameron
L. Liggett, Larry A. Codington, Takashi Oe,
Takefumi Murai, Teruo Naito, Kiyohiko
Ogai, Kiyoshi Nomura, Yuji Takakuwa,
Lemin Huang, Eiko Shimada, and manyother people who have supported and encouraged our work in various ways.

References
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Kenshu Shimada and Norihisa Inuzuka

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975.

Desmostylians from the Miocene Tokigawa Group

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Frontiers, vol. 16, no. I, p.20-24.

• in Japanese•• in Japanese with English abstract

Godo t$ p, Higashi-Matsuyama * t~ ilJ, Iwadono ~~, Kamagata.~, Kamikarako
J:Jl!f.:r, Kuzubukuro1.t~, NegishifJU!'l:, Oppegawa~JllJII, Shogunzawa:j';flIrR, Tokigawa =W~JII.
±~3iw..:ti~O)!f!iT*1f~lt~l}I\I~nl~i.iO)*;ti§llI!Tft1:i: %j.3S.~*t~ilJm1.t~~;::Wffl-t 7.> r:p~
Mt=W~}lIJifrf$O)t$p~~$Jiip iSilte lA.:*tt§ O)"-l1Ill1!i 15 }~ H~WI~;:~a~ 1..,t.:o ;:n is ~;: f;l: Paleoparadoxia t Desmostylus 0) iij 1M iJ~ ~ ::I: n 7.>0) ? i? 12,~ f;l: Paleoparadoxia IM-r:, ~ iS~;: i" O)? i? 5 BiJ~ P. tabatai ~;:IOJJE:-r:~ 7.> 0 llI!i~f;l:J:~O)::R:llI!i, ~ I, ~2, ~ 3 *SllI!i, r~O)~ 3/J\SllI!i t~ 3 *SllI!iiJ~IOJJE:-r:~ t.:o Desmostylus IMf;l:SllI!iO)~
ttJtiJ> is IOJJE: 1.., t.:o 1.t~:tl* f;l: Paleoparadoxia t Desmostylus iJ~1OJ Gilj;fgO) IOJ-Ji!\!!iJ> isil 1.., t.:,~~;::g~iJ~~ 7.> 1..,iJ> 1.." ;: n is iJ~=*1t:o-r:~ 7.> iiJfjgtt >b ~JE:-r:~ 7;t,'o IOJ Gilj;fgiJ> is f;l:~JJlV~, ~.Ji\~ t "·:d.:&1:.nm~L~~~~O)-Ij' Jl1t:O:a:-il 1.." *tt§ O)ti1:.1m:a:-~
0

;:

0

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577~83ftffl-' ::R:~~U~

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 175, pp. 578-586,5 Figs., September 30, 1994

976.

DISCOVERY OF MICROCODIUM TEXTURE FROM
THE AKIYOSHI LIMESTONE IN THE AKIYOSHITERRANE, SOUTHWEST JAPAN*
HIDEAKI MACHIY AMA
Department of Earth and Planetary Sciences, Graduate School of Science,
Hokkaido University, Sapporo, 060

Abstract. Microcodium texture was discovered from a blackish-brown sparry calcite
zone distributed to the south of Mt. Wakatakeyama area, situated in the eastern part of the
Akiyoshi Limestone outcrop. This sparry calcite zone is biostratigraphically situated in theupper part of the Quasifusulinoides sp. A zone, which is overlain by the Montiparus sp. A
zone, and is middle Kasimovian (early Late Carboniferous) in age. According to theformation process of "Microcodium", which is formed secondarily within a meteoric environment, the author proposes to call it microcodium texture, because "Microcodium" is not a
taxonomic unit. From the presence of microcodium texture, it is considered that theblackish-brown sparry calcite zone was formed in a meteoric environment under an exposure
surface developed during the sea-level fall. This suggests that an unconformity (sequenceboundary) is present just above the blackish-brown sparry calcite zone.
Key words. Akiyoshi Limestone, Akiyoshi Terrane, Kasimovian, Microcodium, unconformity, Upper Carboniferous.

(1985) and Sugiyama and Nagai (1990).
Details of the Upper Carboniferous to Permian sequence are, however, still unknown,
because these studies mainly dealt with theLower Carboniferous when the reef was conspicuously developed.
The Akiyoshi Limestone ranges in age
from Early Carboniferous (middle Tournaisian) to Middle Permian (Midian) (Haikawa, 1988; Ozawa and Kobayashi, 1990).
Although this limestone deposition spans
approximately 100 million years, no unconformity has yet been recognized by
sedimentological aspects. Within samples
from the dark brown limestone facies(blackish-brown sparry calcite zone) distributed to the south of the Mt. Wakatakeyama area, "Microcodium" is proved to bepresent. Based on the occurrence of "Microcodium" in the Akiyoshi Limestone, it isformed secondarily in origin within a mete-

Introduction
The Lower Carboniferous to Middle Permian Akiyoshi Limestone, which was deposited on a seamount and accreted in Late
Permian time, is distributed in the westwardof the Akiyoshi Terrane, Southwest Japan.
With regard to the formation of the Akiyoshi
Limestone, Ota (1968) has already made it
clear that this limestone is an organic reef
complex. He concluded that the Akiyoshi
Limestone took the form of an atoll reef in
Middle Carboniferous time. However, there
are few sedimentological studies compared tomany biostratigraphical studies on the limestone using foraminifers and corals.
Sedimentological and paleoecological studies
within the reef have been done by Nagai*Received November 19, 1993; revised manuscript
accepted June 8, 1994
578

976.

Microcodium texture from the Akiyoshi Limestoneoric environment, as has been stated byKlappa (1978). Thus, "Microcodium" isbetter called microcodium texture, because it
is not a taxonomic unit, but is a biogenic
structure. This paper presents the first reporton the occurrence of microcodium texture
from Japan, and examines the formation of
the blackish-brown sparry calcite zone.

Previous work of blackish brownsparry calcite zone
The dark brown limestone facies within thegenerally white-gray Akiyoshi Limestone was
firstly reported as Mg-rich limestone developing over the unconformity at the base of the
Triticites simplex zone by Hasegawa (1963).
Later, he called this limestone facies theblackish-brown sparry calcite zone (BBSC
zone), and discussed its stratigraphic
significance (Hasegawa, 1988). He considered that the BBSC zone might indicate thepresence of an unconformity or an importantgeologic event, such as a catastrophic biological event. In the study of Late Carboniferous to Early Permian fusulinacean biostratigraphy by Ozawa et al. (1991), the BBSC
zone (= dolomitized limestone or dolostonereported by Ozawa et al., 1991, Fig. I) was
recognized in the following five horizons: I)
the upper part of Pseudofusulinella hidaensis
zone, 2) the lower part of Protriticites subschwagerinoides zone, 3) the upper part ofMontiparus montiparus-Quasifusulinoides
ohtanii zone, 4) Montiparus matsumotoi
zone, and 5) the upper part of Triticites(Rauserites) stuckenbergi zone. With regard
to the formation of BBSC zone, Ozawa suggested that lime-muddy limestone was secondarily replaced irregularly by BBSC includingorganic matter, and its formation might takeplace immediately after deposition (T.
Ozawa, pers. comm., 1992). It has also been
considered that the BBSC is not dolomite andis formed under fresh-water conditions (M.
Musashino, pers. comm., 1992). In the studyof the western part of the Akiyoshi Limestone579

by Sano and Kanmera (1991 a, 1991 b), theyalso indicated that the BBSC (= browncolored calcite of Sano and Kanmera, 1991 a,
1991 b) occurred as the replacement of the
Kasimovian (lower Upper Carboniferous) to
Asselian (lower Lower Permian) parent
rocks, and was formed synchronously with or
immediately after the deposition of the
Kasimovian to Asselian parent rocks.

Locality and stratigraphy
The examined samples were collected at thesouthern part of Mt. Wakatakeyama (FigureI), when a joint field survery was carried out
in October of 1990 as a part of joint research
on "The Carboniferous-Permian Boundary inJapan" led by Prof. M. Kato of Hokkaido
University (1990-1993), sponsored by theJapanese Ministry of Education.
According to the fusulinacean biostratigraphy by Ota and Ota (1993), the strata along
the Mt. Wakatakeyama route are divided into
the following eight zones in ascending order(Figure 2) :I) Pseudofusulinella hidaensis Zone,
2) Protriticites matsumotoi Zone (s.s.),3) Quasifusulinoides sp. A Zone,
4) Montiparus sp. A Zone,
5) Schwagerina sp. A Zone,
6) Triticites simplex Zone (s.s.),
7) Pseudoschwagerina muongthensis Zone,
and8) Pseudofusulina vulgaris Zone.
In this route, the BBSC zone is distributedin the Quasifusulinoides sp. A zone (Ota andOta, 1993) and is a few meters thick (Figure2). Thus, it is considered that the horizon ofthis BBSC zone is middle Kasimovian (early
Late Carboniferous) in age. The parent
rocks of BBSC zone including microcodium
texture (=" Microcodium") consist of oncoidbioclastic wackestone, and are interpreted as
low-energy deposits. This lithofacies isunderlain by phylloid algal-bioclastic grainstone/packstone, and overlain by well-sorted
peloid grainstone (Figure 2).

Hideaki Machiyama

580
130'E

132"£

I

I

Akiyoshi Limestone
34'N -r-:::!r..!:I--J--.,...--'

o.....= 2.....==1'4 km
Figure 1. Map showing the measured route (AK Route) and locality of microcodium texture,
Contour interval in the right figure is 2,5 meters, Modified from Ota and Ota (\993),

Description of microcodium texture

4C,40),

Diagnosis.-A cob-shaped subcylindricalClassification and orlgm of microcodium
texture,-"Microcodium " was firstly de-form with a central, thin, cylindrical tube (amicritized cavity) surrounded by browncolored peripheral radial calcite plates,
Each calcite plate takes the form of a "corngrain" (Mamet, 1991), and the stacked plates
show a "corn cob" (Mamet, 1991) form, The
schematic reconstruction of microcodium texture is shown by Figure 3. The corn-grain
plates corrode the surrounding limestones,
Description.-In hand specimens, the BBSC
is abundantly present as irregular spots in theparent rocks, Under the microscope, microcodium texture which corrodes the surrounding parent rocks (oncoid-bioclastic
wackestone) is frequently recognized (Figure
4A), and often occupies more than 80% in
volume of the samples, The microcodium
texture has a cylindrical form, and some ofthem are undulate, They are 1.0 to 1.2 mm
in diameter, and central cylindrical cavities
are about 0.1 mm in diameter, The calcite
plates like "corn-grain" are 0.4 to 0,6 mm inradius, and 0,06 to 0,12 mm thick (Figures 4B,

scribed in the marine Miocene strata of Baden(southern Germany) by GlUck (1912), Fromtheir shape and arrangement of calcite crystals, he established a new species Microcodium elegans, and placed it in the family Codiaceae of the Chlorophyta, However,
because of the peculiar shape of "Microcodium", various origins, such as bacterial,
plant roots, or inorganic, have been put forth
by many workers, In general, "Microcodium" occurs frequently in calcrete (e.g"
Esteban, 1974). Klappa (1978) has discovered recent "Microcodium" under the presentday surface in a rubbly calcareous soil insoutheastern Spain, He has studied its origin in detail, and has made comparison
between ancient and recent "Microcodium".
As a result of his detailed study, Klappa(1978) has concluded that "Microcodium" isthe result of calcification of mycorrhizae, asymbiotic association of fungi and the cortical cells of roots, He has also stated that"Microcodium" is a pedological feature and a

976.

Microcodium texture from the Akiyoshi Limestone

Fusulinacean Zonation

SamplesIi"" AK56t-:-'

Pseudoschwagerina muongthensis z.

Triticites simplex z.

~.~~,

Montiparus sp. A. z.
Protrilicites matsumotoi z.

?

Lithologic
Column~-~fc
iSchwagerina sp. A. z.

581

I

I

I-oc

,

I ....

/

'""'!

, I'"
:I
I
,
I :I
I
I-C

II
I

I
I

I

Pseudofusulina vulgaris z.

I

I

I
I

J

Pseudoschwagerina muongthensis z.

1
Triticites simplex z.

,

1

Blackish Brown
Sparry Calcite Zonerc~

LegendI-oc,..
LLJLLILLI

L i""
1 i:

Bioclastic - Ooid
Grainstone~ Tubiphytes - Bioclastic

I-oc~ Grainstone/Packstone

Schwagerina sp. A. z.
Montiparus sp. A. z.
Quasifusulinoides sp. A. z.
Protnticites matsumotol z.
Pseudofusuline/la hidaensis z.

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Figure 2. The Upper Carboniferous to Lower Permian limestone columnar section and samplinghorizons of AK Route, and lithologic column around the blackish-brown sparry calcite zone. Note thefusulinacean zone between the two double lines is undefined, and fusulinacean zones repeat themselves(Ota and Ota, 1993). A wavy line shows an unconformity. Hand mark indicates the horizon of theblackish-brown sparry calcite zone.

valuable criterion for the recognition of theexistence of a paleosol. This conclusion isin accordance with the opinion of Bodergat(1974), who has demonstrated that the carbon
within the calcite is organic in origin, and has
been metabolized by "Microcodium" in a
meteoric environment. Mamet and Roux
(1982) recognized "Microcodium" in the Carboniferous to Permian of the Canadian Arctic
region (Yukon Territory, Axel Heiberg andEllesmere Islands). Contrary to these opinions, they have emphasized that "Microcodium" has an algal affinity. Later,
Mamet et al. (1987) described "Mi-crocodium" as being questionably a memberof the family Microcodiaceae (Maslov, 1956)
of codiacean algae or incertae sedis. However, Mamet and Roux (1982) interpreted thegrains of" Microcodium" in the grainstones as
reworked grains, such as intraclasts, fromolder deposits. This interpretation suggeststhat "Microcodium" was formed prior to thedeposition of the grainstones. Thus, the formation process of ancient "Microcodium"seems to be similar to that of recent "Microcodium" proposed by Klappa (1978). In
this way, it is considered that "Microcodium"
originates secondarily within a meteoric envi-

Hideaki Machiyama582............

encrusting foraminifers. They concluded
that Osagia is not a genus but a biogenic
structure, and coined the term osagid grains.
In the same way, though Klappa (1978)
preferred Microcodium grain to "Microcodium", the author suggests that the name"Microcodium" be given up, with the structure now in question being better calledmicrocodium texture, because" Microcodium"is a texture rather than a grain.

Formation of blackish brownsparry calcite zone
As mentioned before, microcodium texture(=" Microcodium") is recognized in the BBSCCALCITE PLATE
Figure 3. Schematic. reconstruction of microcodium texture. Calcite plates are 0.4 to 0.6 mm
in radius, and 0.06 to 0.12 mm thick. After Mamet
et al. (1987).

ronment, as has been stated by Bodergat(1974) and Klappa (1978).
As mentioned above, "Mlcrocodium" is nota taxonomic unit such as a calcareous alga,
but a structure related to fungi. That is tosay, "Microcodium" is a biogenic structure
like stromatolites and oncoids. Thus, thegeneric name "Microcodium" must not begiven to this structure. Toomey et al. (1989)
have made a re-examination of the Pennsylvanian to Permian oncoids described previously as Osagia. They have shown that
Osagia consists primarily of tubules of the
cyanobacteria Girvan ella , or its diageneticallyaltered end-product ("algal dust" or "algal
paste"), intimately associated with various

zone of the Mt. Wakatakeyama route. As
shown in Figures 5A and 5B, the microcodium texture together with the parent
rocks is penetrated by dikelets called broken
limestone, which represent the phenomena of
mechanical destruction and the injection ofpulverized particles (Sano and Kanmera,
1991a, 199Ib). Since the formation of broken limestone has been interpreted as related
to the accretionary processes, the above-statedobservation suggests that the microcodium
texture was formed after the deposition of theparent rocks (oncoid-bioclastic wackestone)
and prior to the process of broken limestone(Sano and Kanmera, 199Ib). Thus, thestructure cannot be of modern origin.
From the viewpoint of carbon and oxygenisotopes, the a l3 C value of microcodiumtexture-bearing sample is lower, about 2 permil or less value in al3cPDB (analysts are M.
Musashino, M. Kusakabe, and S. Shin, unpublished data), than samples from the overlying limestones. They compared the resultwith the studies of recent carbonates in Barbados by Allan and Matthews (1977) and theMississippian Newman Limestone in North
America by Allan and Matthews (1982).
The al3 c and 0' 180 values of the vadose zone
in Barbados and of the strata, a few meters inthickness, under the horizon of a developed
paleosol and weathering surface in the New-

976.

Microcodium tex ture from the Akiyoshi Limestone583

Figure 4. Thin-secti o n phot o mi c rog ra ph s of microco dium texture from AK Route. A. Microcod ium texture (corn-grai n ca lcite p la tes : M) corrodes the surro unding p arent rock (oncoid-bioc las ti cwackestone : Pl. Sca le bar is 2 millim eters in length. B. Sli ghtl y o bliquel y c ut tran sverse secti o n ( left)
a nd lo ngi tudin a l section (rig ht ) o f mi crocodium texture (M) . Note co rn-gra in ca lcit e pl a tes (e) a nd a
centra l thin micriti zed ca vity (arrows). Scale bar is 0.5 millimeters in length . C. Slightl y ob lique ly c ut
tra nsve rse sec ti o ns of mi crocodium textu re (M) are prese nt as irreg ul ar ly di stributed spots in the parent
rock (P). No te peripheral rad ia l ca lc ite pl ates (e) and a central thin cy lindri ca l tube (a rrow) . Sca le ba r
is 0 .5 millimeters in len gt h. D. Obliqu e sec ti o ns of mi croco dium texture (M) . N o te "corn cob" form
stacked by ca lc ite plates (e ). Sca le ba r is 0.5 millimeters in length.

man Limestone a re lower than those of theoverlyin g a nd underlying strata. In genera l,
it is known that 0' 13C and 0' 18 0 va lues a re low
in a meteo ric environment (e.g. , Scoffin ,1987). Thu s, as h as been pointed o ut by
Mu sashin o et al . (unpublished data) , it isconsidered that the a ppeara nce of a meteoric
enviro nment developed during a sea-leve l fa ll
was the ca use of forma ti o n of the BBSC zone .
Thi s is in acco rdance with the or igin of
microcodium texture rep orted by Kl appa
(1978) . In additi on , the presence of microcodium texture was o ne of the diagno stic

features of caliche (calcrete) facies (Estebana nd Klapp a, 1983). From the above, it iscon sidered th at the BBSC zone within the
Quasifusulinoides sp. A zo ne and below theMontiparus sp. A zo ne was formed by theform ation of m icrocod i um texture together
with possi ble calc rete genesis . That is to say,a hi at us wit h an exposure s urface may bepresent. Thi s s uggestion is in agreementwith the result of the fusulinacean biostra tigrap hy by Ot a and Ota (1993) , who supposed
the presence of a strat igra phic a l gap between
the Quasifusulinoides sp. A zo ne and theHideaki Machiyama

584

Figure 5. Thin-section photomicrogra phs of microcodium texture and its destruction. A. Microcodium texture (M) is penetrated by complexly anastomosing comminution zones (arrows). Scale bar
is I millimeter in length. B. Close-up of A. Scale bar is 0.5 millimeters in length.

Montiparus sp. A zone. This suppositions upports Hasegawa's opinion (Hasegawa,1988), though Ota and Ota (1993) havepointed out th at no catastrophic biologicalevent occurred at the time. The author has
not been able to clearly recognize other features of calcrete facies around the BBSC zone.
In the future, it will be necessary to study the
successions of BBSC zone in detail , and torecognize an exposure surface.
Conclusion
As a result of the study of samples from the
BBSC zone in the Quasifusulinoides sp. A
zone of Ota and Ota (1993), situated to theso uth of Mt. Wakatakeyama area in the eastern part of the Akiyoshi Limestone, the BBSC
zo ne proves to contain " Microcodium."
According to the formation process of "Microcodium" by Klappa (1978) , who has
demonstrated that " Microcodium" is the products of calcification of mycorrhi zae , asy mbiotic associat ion between fungi and root
cortical cells, the author s uggests calling "Microcodium" microcodium texture, because" Microcodium " can not be a ta xo nomic unit.
From the genesis of microcodium texture, theiso tope study , and the fusulinacean bio stratigraphy, it is thu s inferred that the BBSC zo ne

was formed in a meteoric environment possibly under an exposure surface developed
during a sea-level fall. This suggests that an
unconformity is present in the BBSC zone.
As mentioned before, Ozawa et at. (1991)
have recognized five horizons of the BBSC
zone aro und the Carbon i ferous- Perm ianboundary. Sano and Kanmera (1991 a ,1991b) have also reported BBSC zones (theirbrown-colored calcite) in the Kasimo vian toAsselian parent rocks of western part of the
Akiyoshi Limestone. Their brown-coloredcalcite is clearly interpreted as microcodium
texture (Sano and K a nmera, 1991b: PI. VI ,Figs. 1- 5). From these facts , microcodium
texture possib ly exists in many horizon s.
Hereafter, these may provide good marker
horizons showing a seq uence bound ary forsequence stratigraphy studies , because they
are interpreted as being formed in a meteoric
environment appearing with a sea-level fall.
The BBSC zone is also known in the Omi
Limestone (Y. Hasegawa, pers. comm. , 1993) ,and this zone is in almost the same horizon
with the Akiyoshi Limestone (the horizon
between the Fusulina-Fusulinella zone andthe Triticites zo ne by his zonation sc heme).
Thus, there is a possib ility that this particul arhorizon indicates the tract of a global sealeve l change. As detai led foram i n i feral

976.

Microcodium texture from the Akiyoshi Limestone

zonation schemes are proposed (e.g., Ozawa
and Kobayashi, 1990), it is expected that
more details pertaining to global sea-levelchanges will be compiled if system tracts
should be recognized by studies of limestone
petrography, stable isotopes, and diagenetic
sequence stratigraphy (Kano, 1992).

Acknowledgments
The author is grateful to Professor Makoto
Kato of Hokkaido University for valuablesuggestion during the course of this work, andDr. Makoto Kawamura of Hokkaido University for critical reading of the manuscript.
The author wishes to thank Professor Yoshiyuki Hasegawa of Niigata University andProfessor Tomowo Ozawa of Nagoya University for permitting me to quote their unpublished data on the blackish-brown sparrycalcite zone. The author also wishes tothank Professor Makoto Musashino of Kyoto
University of Education for permitting me toquote his unpublished geochemical data.
The author wishes to acknowledge Associate
Professor Toshio Kawamura of Miyagi University of Education and Mr. Takehiko Haikawa of Akiyoshi-dai Museum of Natural
History for help in the field. Thanks are also
due to Messrs. Toshiaki Kuwajima and
Hidehiko Nomura, Technical Staffs of Hokkaido University, who helped me to makethin sections.
A part of this work was supported by aGrant-in-Aid for Scientific Research from theJapanese Ministry of Education.

References cited
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tools: data from surface and subsurface of Barbados, West Indies. Geology, vol, 5, p. 16-20.
Allan, J.R. and Matthews, R.K., 1982: Isotope signatures associated with early meteoric diagenesis.
Sedimentology, vol. 29, p.797-817.
Bodergat, A.M., 1974: Les microcodiums, milieux etmodes de developpement. Docum. Lab. Geol.

585

Fac. Sci. Lyons, vol. 62, p. 137-235.
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Esteban,1973, p. 105-125.
- - - , . and Klappa, C.F., 1983: Subaerial exposure, p. I-54, In, Scholle, P.A., Bebout, D.G. andMoore, C.H. eds.. Carbonate depositional environments. AAPG, Mem., no. 13.
G1iick, H., 1912: Eine neues teinbildende Siphonee(Codiacee) aus dem marinen Tertiiir von Siiddeutschland. Mitt. bad. geol Landesanst. Bd.,
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Haikawa, T., 1988, The basement complex andconodonts biostratigraphy of the lowest parts in
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abstract)
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Pal€ozoi"qu superieur de I'Arctique canadien.
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USSR. Trans. A cad. Sci. USSR Geol. Inst., no.
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Nat. Hist., no. 20, p. 1-15, pis. 1-6.
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1-31. (in Japanese with English abstract)Hideaki Machiyama

586

Ota, Y. and Ota, M., 1993: Faunal change of theUpper Carboniferous to Lower Permian
fusulinaceans from the Akiyoshi LimestoneGroup, Southwest Japan: On materials along
the AK Route, adjacent to the Akiyoshi-dai
Museum of Natural History. Bull. Akiyoshidai Mus. Nat. Hist., no. 28, p. I-57, pis. 1-3. (inJapanese with English abstract)
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to Permian Akiyoshi Limestone Group. In,
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to Early Permian sequence of Akiyoshi limestone Group, Japan and its correlation withreference sections in the Tethyan Region. Saito
Ho-on Kai, Spec. Pub., no. 3, p.327-341.
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Akiyoshi tk"E. omi.Wi.

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Geol. Soc. Japan, vol. 97, p. 113-133.
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grains from a Lower Permian Midcontinent limestone. Palaios, vol. 4, p. 51-62.

Wakatakeyama :t=t'nlI.

'*"E:SEk~t.1' I? (J) microcodium ~.H~(J)~jt: tk"EEEk:!5*$O):t=t'nlIi¥i1J I;: ?t;ffi''t'.o
mmts sparry calcite *tJ, i? microcodium M~ .5i!,v,t! L..t..:o :: O)mmts sparry calcite
1;I:*-1iill!;tl.?t*tJ'i? Quasifusulinoides sp. A * c Montiparus sp. A *O)ra' 1;:{ftUi[ L.. L:to ~.
1lif1~ I¥J I;: IH&WJ:O Eiac (Kasimovian r:p WJ) I;: ~ RlG ~ h t..: {) 0) c c i? ;z i? h .0 "Microcodium" l;l:tl~O)mO)ElJlk:lllJm c ii~ c O)~~j:J;: J: .0 mycorrhizae O):OEk1tO)~~-r­~ ~ l=.~fi c I;l:wg/ib i?h7d::v'O)-r-. ::h~ "microcodium *.H~" cll'¥f!F't' .o.H~~'t'.o omicrocodium *.H~O)ff:tE~mmts sparry calcite *O)ER~· ~~"'-'{ft1*frnItJ~mJImO) {) 0) J: ~fl£v':: c tJ, i? :: O)mmts sparry calcite *1;l:Wi7Jd\!ifl£""fIlifI;::tIB~H;:alfj L.. t..:~O)~*~tI""f-r-~RlG~ ht..: {) 0) c ~;z i?h.o o L..t..:tJ~'? L mmts sparry calcite *1;l:1'~.g- (y-?..I.
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589

Palaeontological Society of Japan (PSJ) Council Actions
During its meeting on June 24, 1994, the PSJ Council enacted the followingchanges to PSJ membership.
New members elected:
Yutaka Hara,
Shogo Konishi,
Y oshito Nakashima,
Takenori Sasaki,
Hajime Yokoi.

Seiiti Kamada,
Miwa Maruyama,
Takashi Nishimura,
Kenji Shimizu,

Resigned members:(Fellow)
Seiichi Mabuchi,

Shunji Watari.

(Ordinary member)Yutaka Tsubaki,

Kyoji Takasaki.

Deceased members:(Fellow)
Hiroshi Ozaki.
(Ordinary member)
Jost P. Wiedmann,

Regionald Wright Barker.

Yoshio Kataoka,
Taisuke Murata,
Hiroshi Oda,
Katue Yamane,

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Transactions and Proceedings of the PalaeontologicalSociety of Japan

September 30, 1994

New Series No. 175

CONTENTS
TRANSACTIONS
973.

Xuedong Xu and Hiroshi Ujii€: Bathyal benthic foraminiferal changes
during the past 210,000 years: Evidence from piston cores taken from seas
south of Ishigaki Islands, southern Ryukyu Island Arc .................. 497

974.

Hiroshi Nishi, Ashraf M.T. Elewa, and Kunihiro Ishizaki: Planktonic foraminiferal biostratigraphy of Upper Paleocene to Middle Eocene sequences inthe Eastern Desert area, Egypt ........................................ 521

975.

Kenshu Shimada and Norihisa Inuzuka: Desmostylian tooth remains from
the Miocene Tokigawa Group at Kuzubukuro, Saitama, Japan976.

.......... 553

Hideaki Machiyama: Discovery of microcodium texture from the Akiyoshi
Limestone in the Akiyoshi Terrane, Southwest Japan .................... 578

PROCEEDINGS.......................................................... 587