T ransactions and Proceedingsof thePalaeontological Society of Japan
New Series

No. 97

Palaeon to log ica l Society of JapanAp r il 30, 1975

EditorTakashi HAMADA

Associate Editor Ikuwo OBATA

Officers for 1975 - 1976
Honorary President:

Teiichi KOBAYASHI

President: Tatsuro MATSUMOTO
Councillors (*Executive):*Kazuo ASAMA, Kiyoshi ASANO, *Kiyotaka CHINZEI,*Takashi HAMADA, *Tetsuro HANAI, *1 taru HAY AMI, Tadao KAMEl,*Kametoshi KANMERA, *Tamio KOTAKA, *Tatsuro MATSUMOTO, Tokio
SHIKAMA, Tsugio SHUTO, *Yokichi TAKAYANAGI, Toshimasa TANAI,*Hiroshi UJIIE
Executive Committee:
General Affairs: Tetsuro HANAI, Itaru HAYAMI, Kiyotaka CHINZEI, Saburo
KANNO, Y asuhide IWASAKIMembership:

Kazuo ASAMA, Kazuhiko UEMURA

Finance:

Hiroshi UJIIE

Planning:

Tamio KOTAKA, Hiroshi NODA

Publications
Transactions: Takashi HAMADA, Ikuwo OBATA
Special Papers ~ Kametoshi KANMERA, Ienori FUJIY AMA, Tomowo OZAWA"Fossils":

Yokichi TAKAYANAGI, Toshiaki TAKAYAMA

Fossil on the cover is the six leaves in a whorl of Trizygia oblongifolia(GERM. & KAULF.) ASAMA from the Maiya formation (Parafusulina zone),
Maiya, N. E. Japan.
All communications relating to this journal should be addressed to the
PALAEONTOLOGICAL SOCIETY OF JAPAN
c/o Business Center for Academic Societies, Japan
Yayoi 2-4-16, Bunkyo-ku, Tokyo 113, Japan
Sole agent:

University of Tokyo Press, Hongo, Tokyo

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 97, pp. 1-6, April 30, 1975

AMMONITOLOGY IN JAPAN-A HISTORICAL REVIEW(Presidential address, Palaeontological Society of Japan, 1975)
TATSURO MATSUMOTO
Department of Geology, Kyushu University, Fukuoka 812

B*K~~~7~~~1~~~~~:h~OOK~~~7~~~1~~~~~~, ~~~.

~1l~4i!.J~~f6~.!::, ~~iHcht-: "" -C ~ B*~~~~ ~5tt.51!Wvc~ ? ffltJ:* ~ ~ ' 0 ~ J: yC
100 if.~~5I:: ~*~Ij-t ~ .!::, iX~ 4 W:~lc:B-~ ~ .: .!:: tJ:-(- ~ ~o~~1:M (1873-1915) mln;*~ (1l:!i1!:EfJ~/:"77); ~2Wl (1920-1950) L.F. SPATH
fl1i:± I? (l)~l1v'~~T, Jl1I~ (1920-1935) ~:N&:WF~* (m7.Kfl1i:±yC~{tl!.) ~t.5!IVJ, ~~ (19361950) ;t< A ~ m7.K (l&~~7,t.); !it 3 jtJl (1951 ]jJl$) 1iif~tt.51fjl;lEE~ (~t Icn'-~ Ht::fi~1f
IR:B- . xtJt) (Treatise f±l1:RJl1I1~~OO~EfJ:x:drO; !it 4 Wl (!it 3 Wl.!::~lli: V::>"?¥t*",) /~v::t /~ 1 ::t p ~ :h /1-- t.elm t t.5f6ft
1e~~r,~t6. }t~~%:1JvC~;Wf 1...-, OO~EfJ~J1;;HJI.!ff.!::Jtl!Bj(~¥o~EfJ~~'~~ t ",,-C, 4-~~'""yC? ~JE~HltJ' IJ t-:~'otl*~a~The history of' researches on ammonites in our country may be divided infour major stages, depending much on
the world development of palaeontology
and also on the activities by Japanesepalaeontologists for generations.
The first stage, until 1915, is characterized by monographic works. The ammonites obtained by pioneers' geologicalreconnaissance in various parts of Japan
were described by MOJSISOVICS (1889),
YOKOYAMA (1890, 1904a, b), JIMBO (1894),
Y ABE (1901-2, 1903-4, 1909, 10, 14, 15)
and DIENER (1915). The results were
useful for the age determination of Mesozoic formations. Two interesting heteromorph genera, Pravitoceras and Nipponites, were discovered by Y ABE (1901, 4)
in this stage. For some reasons (probably
affected by W orId War I), there is ablank of activity for 1916-1920, but anissue of a revised textbook of palaeontology (in Japanese) by YOKOYAMA in 1920.
The second stage, from 1920 to 1950 isunder a strong influence of L. F. SPATH'S
works. It is subdivisible into two substages. The earlier half, for 1920-1935,
is characterized by SHIMIZU'S activity(,26a-b, 27a-b, 30a-d, 31a-c, 32, 34, 35a-b),
besides works by Y ABE and SHIMIZU (,21,24, 25a-b, 26a-b, 27), YEHARA (,25, 26, 28),SHIMIZU and JIMBO (,33), TOKUNAGA andSHIMIZU (,26), KAWADA (,29) NAGAO (,31ab, 32a-b) and KOBAYASHI ('35) for the descriptions of Mesozoic ammonites. These
were within the framework of the systematics proposed by SPATH, who seemed
to have classified the Ammonoidea on his
philosophical basis of iterative evolution,and other authorities in Europe andAmerica.
The biostratigraphic results in thisstage were summarized by Y ABE andSHIMIZU ('33) for the Triassic, MABUTI('33) for the Jurassic and Y ABE (,27) andSHIMIZU (,31, 35) for the Cretaceous.
Only a species of Permian ammonite wasreported in this substage (MABUTI, '35).
1

2

Tatsuro MATSUMOTO

The later half, 1935-1950, is represented
by a number of shorter papers, for instance HAYASAKA (,40) on two Permian
species, Y ABE (,49) on an uncoiled (?)
Triassic ammonite, KOBAYASHI (,47), KoBAYASHI and FUKADA ('47a-c) and FUKADA ('50) for some Jurassic ones, and
MATSUMOTO'S (1936, 38a-c, 42a-d, 47)preliminary results of studies on Cretaceous ammonites. The apparently lessactive situation was complementary withvery active works by KOBAYASHI on
Lower Palaeozoic nautiloid cephalopods
from China and Korea and on non-marine
fossils from the Mesozoic of East Asia.
The field works, as exemplified by MA TSUMOTO ('42-43) and MATSUMOTO and ONO('47), however, constructed foundations
for further advances in the next stage.
The research works in the third stage,
since 1951, have been much stimulated
by international exchange of knowledge,
aided by publications of such comprehensive works as the Treatise, the Osnovy
etc., and by airway transportation. A
great number of papers have been published for the up-to-date descriptions ofammonites from Japan :-HAYASAKA (,54,63), IGO (,64), Y ANAGISA WA ('67), NISHIDA('71) and BANDO ('75) on some Carboniferous and Permian ones, which are still
awaiting further descriptions; NAKAZA WA and SHIMIZU (,55), NAKAZA w A (,57,
58a-b, 64, 71) (S. W. Japan), SAKAGAMI(,55), KUMMEL and SAKAGAMI ('60) (Iwai),
ONUKI and BANDO (,59a-b), BANDO ('64a-.
c, 66, 67a-b, 68a-b, 70,71,73), BANDO et a1.
(,70, 74) (Kitakami etc.), and ISHIBASHI(,70, 72, 73, 75) (Okinawa and Tanoura) on
the Triassic ammonites; SATO (,54a-b, 55,
56, 57, 58, 59, 61c-d, 62a-c, 72,74), SATO
and KANIE (,63), SUZUKI and SATO (,72),
MATSUMOTO (,56), MATSUMOTO and HIRATA (,70), TAKAHASHI (,69, 73) and HIRANO(,71, 73a-b) on the Jurassic ones; OBATA('67a-b, 69, 73, 75), OBATA et al. (,75),

MATSUMOTO et a1. (,52, 66, 68, 69), NAKAI
and HADA (,66), NAKAI and MATSUMOTO(,68), NODA (,72), SATO (,61) and T AKAHASHI (,73) on the Lower Cretaceous ones,
HAYASAKA and FUKADA (,51), WRIGHT
and MATSUMOTO (,54), MATSUMOTO ('53,
54a-b, 55b-c, 56, 57, 59, 60, 63, 65a-b, 67,
69, 70a-b, 71, 73b, 75) MATSUMOTO et al.
(,53, 54, 55, 56, 57, 63a-b, 64, 66, 67a-b,
69, 72, 75) OBATA (,65), SAITO (,58-59,6162), HASHIMOTO ('73), HIRANO ('75) and
TANABE ('75) on the Upper Cretaceous
ones. Some of these works have contributed to improve considerably the taxonomic framework of certain families, e. g. 'Desmoceratidae, Pachydiscidae, Kossmaticeratidae, Acanthoceratidae, Collignon iceratidae, Nostoceratidae and Otoceratidae.
The biostratigraphic results are alsosignificant in establishing a reference
scale for the circum-Pacific areas andalso in attempting zonal correlation withother standard or reference scales of theworld, although there are further problems to be settled.
In the third stage the activities ofJapanese palaeontologists are extended
overseas to the ammonite faunas andtype-specimens from certain areas as seenin the results of NAKAZAWA and BANDO(,68), KAPOOR and BANDO (,74), BANDO(,75), ISHIBASHI (,75), SATO (,61a-b, 63,
72, 75), KOMALARJUN and SATO (,64),
MATSUMOTO (,55, 59b, 59-60a-c, 60, 66a-b,73a), MATSUMOTO et al. (,58, 65, 66, 67,69), and OBA TA et al. (,75). They havecontributed to the. knowledge of international correlation and world palaeobiogeography.
The fourth stage has started already,overlapping the third, and will continue
further on. By this I would mean thegradually increased importance laid on
palaeobiological studies. SCHINDEWOLF'S(1968) comments on ammonitology may

Ammonitology in Japan
mark a stimulating milestone for thistrend.
To understand the lively ammonoids it
is important to study the shell structure,
its ontogenetic development, its functional
morphology, its relation to the soft part,as well as the soft body itself. The
analysis from population to population on
the stratigraphically well sorted material,
combined with palaeoecology and palaeo·biogeography, would be essential to know
the true state of evolution in the Ammonoidea. The results would give foundations for more natural classification andmore precise zonation or correlation, as
well.
Along these lines the works done in
our country are still in the infancy, although there were some. SHIMIZU (29, 34)
once examined through microsection thesiphuncle and other shell characters inearly ontogeny on some well preserved
ammonites from Hokkaido and Sakhalin.
This was an adventurous attempt but
has been little developed further, until
HIRANO's ('75) recent recommencement
on similar material by means of up-todate methods. OBATA ('59, 60) has illustrated through longitudinal section theformula of spiral growth in some ammonites which show more than one phases
in ontogenetic changes. On several occasions I endeavoured to make clear the
ontogenetic development of sutures incertain genera and the results have beenused by SCHINDEWOLF for his comprehensive and systematic treatment.
Dimorphism in ammonite species has
recently received special attention. Although positive evidence has not been
given for the interpretation of sexual
dimorphism with the material from Japan,
examples of lappet-bearing smaller forms

3

as compared with commonly known
larger shells of the Puzosiinae have been
recently reported by MATSUMOTO et al.
('72). JORDAN and I not'ice examples of
injured ammo"nites from Japan. This kindof study (not yet published) would giveinformation on whereabouts of anatomically important portion of the soft bodyand also on the mode of life. A palaeobiochemical study, attempted by FUJIWARA (,61) on an ammonite, awaits advances in proper way.
On the basis of the favourable materialof fossil population in a zone of the Ikushumbetsu sequence OBATA ('65) studied
the ontogeny and allometry of Reesidites
minimus and its relation to Subprionocyclus normalis from the underlying zone
(Turonian). This is going to be improved
by REYMENT ('75) by more precise mathematical treatment. TANABE ('75) attempts
to clarify the chronological change ofshell characters and its functional meaning in Turonian species of Otoscaphites
and ScaPhites from Hokkaido. This would
serve as a step for further improvementof the concept of the life zone of ammonite species, as suggested by HAY AMI('73).
The above works may foreshadow afraction of the activity in the fourthstage and I would hope further development in paiaeobiological aspects of ammonitology, keeping pace with the advances
in taxonomic and biostratigraphic aspects.
<

References
References are omitted for brevity. See
the chronological table (appendix) and also
the bibliography in the Palaeont. Soc; Japan
SPecial Papers Nos. 1, 9 and the forthcoming
issue.

Tatsuro MATSUMOTO

4Appendix
Data for a historical review of ammon ito logy in Japan-Chronological table of works (shortened titles)Abbreviation: Amm. =Ammonites, ammonoid, Cr. =Cretaceous, Jr. = Jurassic, Tr. =Triassic,
L.=Lower, M.=Middle, Up.=Upper, F=formation, J=in Japanese, *=Palaeobiological work
1876.
1889.
1890.

(LYMAN: Geol. sketch map Yesso.)
MOJSISOVICS: Japan. Trias-Fossilien
NEUMAYR: Jura in NAUMANN & NEuMAYR: Geol. Pal. Japan; YOKOYAMA:
Verstein. japan. Kreide
1894. JIMBO: Kreide Hokkaido; YOKOYAMA:
Text-book [J] [ZITTEL, 1876-93: Handbuch]
1900. [HYATT Cephalopoda in ZITTEL-EASTMAN'S Text-book]
1901-2. YABE : 3 Up. Cr. Amm. (=Pravitoceras)
1903-4. YABE: Cr. Ceph. Hokkaido, I-II (=Nipponites)
1904. YOKOYAMA: Jr. fossils Rikuzen; Jr.
Amm. Echizen & Nagato
1907. Y AKOY AMA: Text-book [J]1909. YABE: Strati. & Pal. Ob. Kreide Hokkaido & Sakhalin
1910. Y ABE: Scaphiten Hokkaido
1914. Y ABE: Amm. Tosa (Shikoku)
1915. DIENER: Triasfaunen; Y ABE: Cr.
fossils Awaji & Toyajo

1928.
1929.
1930.

1931.

1932.

1933.

1934.

1935.

[1914-18 World War I]
1920.
1921.
1924.
1925.

1926.

1927.

YOKOYAMA: Revised Text-book ofpalaeontology [J]YABE & SHIMIZU: Cr. Amm. Japan &Calif.
Y ABE & SHIMIZU: Brahamites Sakhalin
YEHARA: L. Tr. Amm. Nomura (Shikoku); Y ABE & SHIMIZU: Crioceras
from Oshima; Prionotropidae, I
YEHARA: Tr. Fauna Sakawa (Shikoku); Y ABE & SHIMIZU: Parapachydiscus; SHIMIZU in YABE et al.: Cr.
Moll. Sanchu Graben; SHIMIZU: 3 interesting Cr. Amm.; Choshi Cr. [J];TOKUNAGA & SHIMIZU': Cr. Futaba[Pan-Pacific Sci. Congr. Tokyo]
YABE & SHIMIZU :Tr. fauna Rifu;
SHIMIZU: Remarks on 2 Amm. Sakawa;
Perisphinctes from Soma; YABE: Cr.
Stratigr. Japan. lsI.

YEHARA: L. Tr. Ceph. Shikoku
KAWADA: 2 Amm. from Naibuchi;*SHIMIZU: Siphuncle [J]SHIMIZU: Tr. Amm. Sakawa; Anisic
Amm. Kitakami; Ladinic Amm. Rifu;
SHIMIZU: 2 Tithon. sp. Perisphinctesfrom Koike (Soma)
SHIMIZU: Carnic Proarcestes Shikoku;
Tithon. Streblites, Koike (Soma) ; SHIMIZU: L. Cr. Amm. Japan; NAGAO:
Cr. Anaptychus like bodies; Anaptychus& Aptychus
NAGAO: Jr. Cornaptychus; Desmocerasoperculum; SHIMIZU: Senon. Amm.
Pseudobarroisiceras
YABE & SHIMIZU: Tr. deposits Japan;
SHIMIZU & JIMBO: L. Tr. Amm. Tao[J]; MABUTI: Jr. strati. S. Kitakami*SHIMIZU in SHIMIZU & OBATA, T.:
Cephalopoda [J] [Iwanami series];*NAGAO & SAITO: Septal features
MABUTl: Stacheoceras from Kitakami(Perm.); KOBAYASHI: Jr. Torinosu;
SHIMIZU: So-called Hamites; Up. Cr.
Ceph. Japan, I[Pal. Soc. Japan established]

MATSUMOTO: So-called Pachydiscus
egertoni
1938. MATSUMOTO: Goshora fauna (= Pseudouhligella); MATSUMOTO: Zelandites;
Naibuchi biostrati.
1940. HAYASAKA: 2
Amm.
Kitakami(Perm.) ; NAGAO: Praestriaptychus(Jr.)
1941. *MATSUMOTO: Interspecific relationships [J]1942. MATsuMoTO: Notes on Desmoceratinae; Gaudryceratidae; Tetragonitidae; Phylloceratidae
42-43. MATSUMOTO: Fundamentals in Cr.
Strati.
[1939-45 World War II]
1936.

Ammonitology in Japan
1947.

1949.
1950.
..

KOBAYASHI & FUKADA: Ataxioceras;
Katroliceras; Discosphinctes; MATSUMOTO & ONO: Biostrati. Jr. Toyora[JJ; KOBAYASHI: Seymourites & Jr.
palaeogeography; MATSUMOTO: L. Cr.
Amm. Yuasa. [J]YABE: Rikuzenites from Tr. Kitakami; FUKADA: Atlas Jr. Amm. [J]FUKADA: Perisphinctes ozikensis-----.-.-------~-----------

1951.

1952.
1953.

1954.

1955.

1956.

1957.

1958.

..------------------------ -----------.-- ...... _---._ ..... __ ........... .

[Pa!. Soc. Japan, Trans. Proc. N.S.
No.1; Special Pap. No. 1J
HAYASAKA & FUKADA: Ontogeny ofBarroisiceras minimum; MATSUMOTO& MAEDA, Y. : Pachydiscus from Awaji[J]
MATSUMOTO et a!.: Cr. Amm. undivided Meso.
MATSUMOTO & HASHIMOTO: Pseudaspidoceras; MATSUMOTO: Ontogenyof Metaplacenticeras
HAYASAKA: Young. Palaeoz. Ceph.
Kitakami; SATO: Tmetoceras; Hammatoceras Kitakami; MATSUMOTO(ed.) : Cr. System japan. Is!.; Selected
Cr. leading Amm.; MATSUMOTO &SAITO, R. : Smooth Pachyd. ; WRIGHT &MATSUMOTO: Doubtful Cr. Amm.
genera; MATSUMOTO: Puzosiidae; KoBAYASHI et a!.: Palaeont. I [J] -Asakura
NAKAZA WA & SI-llll-IlZU: Glyptophiceras
from Hyogo; SAKAGAMI: L. Tr.
Amm. Iwai; SATO: Amm. Kuruma(L. Jr.); MATSUMOTO: Evolution of
Peronicera tidae ; MATSUMOTO: Kossmaticeratida.e; Bituberculate Pachyd. ;MATSUMOTO & OBATA, I.: Up. Cr.
Desmoceratidae
SATO: Karakuwa (M. Jr.) ; Correlation
L. Jr. [J]; MATSUMOTO: Yebisites (L.
Jr.) ; MATSUMOTO: Kossmaticeratidae,
further notes; MATSUMOTO & SAITO,
R. : Cenomanian Damesites
NAKAZAWA: Monophyllites [JJ; SATO:
Shizukawa (L. Jr.); MATSUMOTO:
Turonian Damesites; MATSUMOTO,
SAITO & FUKADA: Some Acanthoceratids
NAKAZAWA: Monophyllites arakur-

5

ensis; Tr. system Maizuru; SATO:
Shizukawa, supplement; MATSUMOTO& MILLER: Cr. Amm. Kansas
58-59. SAITO, T.: Cr. fossils Nakaminato, III
1959. NAKAZAWA: 2 ceph. Nariwa; ONUKI& BAN DO : M. Tr.. Amm. Rifu; Tr.
Amm. Isatomae; SA TO : Berriasian in
Kitakami; *OBATA: ·Croissance relative sur Desmoc.; MATSUMOTO: Zonation of Up. Cr. Japan; Cr. Amm.
Alaska59-60. MATSUMOTO: Up. Cr. Amm. California,
I-III
1960. KU?,.,IMEL.& SAKAGAMI: Mid-Scyth.
Amm. Iwai; SATO: Courants oceaniques fro ids Jr. Japonais; MATSUMOTO: Graysonites from Kyushu;
Type Amm. Cr. Gulf Coast [J];*OBATA: Spirale de Amm.
1961. [Pa!. Soc. Japan: Catalogue of TypespecimensJ
SATO: Aalen. Amm. Mae Sot, Thai!.;Oxf. Amm. Mindoro, Phi!.; SATO: Jr.Cr.; Berr. & Tith. fauna; *Ft:'JIWARA:
Amino-acid Cr. Amm. [J]61-62. SAITO, Toshio: Up. Cr. Ibaraki &Fukushima, I-II;
1962. SATO: Biostr. Amm. Jr. Japon; Jr.
Jap.-Amm. Zones; Zones d'Amm. Jr.
[JJ; MATSUMOTO & UEDA in UEDA:
Type Himenoura
1963. [Pal. Soc. Japan: Revision of Classical
MonographsJ
HAYASAKA: Perm. Amm. Kitakami;
SATO: Amm. Tr. Malaisie; SATO &KANIE: Lillaetia; MATSUMOTO &OBATA: Baculitidae;* Baculites-facies[J]; MATSU:\WTO & OBATA: Bevahites
from Shikoku; *MATSUMOTO: Ontogeny & evolution [J]1964. IGo: Goniatites Hida; MURATA: Kanokura (list of Perm. Ceph.); NAKAZAWA: Anisian fauna Shikoku; BANDO:
L. Tr. and Tr.-Perm. [J]; Tr. Strati.
& Amm. fauna Japan; Mid. Tr. ceph.
Jap.; KOMALARJUN & SATO: Aalen.
(Jr.) Amm. Mae Sot, Thai!.; MATSUMOTO et a!.: Yabeiceras; MATSUMOTO:
Cr. Ceph. faunal changes [J]

6
1965.

1966.

1967.

1968.

1969.

1970.

Tatsuro MATSUMOTO
MATSUMOTO et al.: Buried Cr. W.
Taiwan; MATSUMOTO: ColJignoniceratidae, I-II; *OBATA: Allometry ofReesidites minimus
BANDO: Note on Tr. Amm. ; NAKAI &HADA: Apt. Amm. Shimanto; MATSUMOTO et al.: Mesoz. Amm. AmamiOshima; MATSUMOTO & OBATA:
Acanthoc. Sakhalin; MATSUMOTO:
Amm. Cura~ao; MATSUMOTO, SASTRY& SARKAR: Notes on Cr. Amm. S.
India, I; MATSUMOTO: Amm. flaccidicosta, Texas; MATSUMOTO & NODA:
Amm. bravaisianus
Y ANAGISA WA: Geol. Pal. Takakurayama (Perm.); BAN DO : Tr. Amm.
Inai; M. Tr. Amm. & strati. [1];OBATA: Valdedorsella Miyako; Silesitids (Miyakoceras); MATSUMOTO:
Nostoceratidae; MATSUMOTO & KANIE: Ainoceras; MATSUMOTO & MURAMOTO: 2 heteromorph Amm.; SUYARI
et al.: Shimanto [1]; MATSUMOTO &SASTRY: Notes on Cr. Amm. S. India,II
BANDO: U. Perm. & L. Tr. ceph.
faunas [1]; BAN DO : L. Tr. Amm.
Kitakami & Maizuru [1]; NAKAZAWA& BANDO: L. & M. Tr. Amm. Timor;
ANDAL et al.: Jr. Mansalay F., Philippines; HANAI et al. : Cr. Miyako Group[1]; NAKAI & MATSUMOTO: Amm. Cr.
Fujikawa (Shikoku); MATSU~IOTO in
MATSUMOTO et al.: 2 Cr. Amm. Tomochi (Kyushu)
TAKAHASHI: Jr. str. & Amm. fauna,
Kitakami; OBATA: Douvilleiceratids
Miyako; MATSUMOTO & HIRA:r A:
Amm. Shimanto; MATSUMOTO et al.:
Selected Acanthoceratids; MATSUMOTO & OTSUKA: Amm. Y. OGAWA
Collection [J]; MATSUMOTO: Collignoniceratidae, IIIBANDO: L. Tr. Amm. Kitakami; BANDO & ARAKI: Glyptophiceras from
Hiraiso (K.itakami) [J]; ISHIBASHI:
Up. Tr. Amm. Okinawa, I; *SHIKAMA& HIRANO: Mode of occurrence(Toyora Amm.); MATSUMOTO &HIRATA: Jr. Amm. Kuraoka (Kyushu)

1971.

1972.

1973.

1974.

1975.

[1]; MATSUMOTO: Collignoniceratidae,
IV; Uncommon keeled Amm.
NISHIDA: Carbo Amm. Akiyoshi; BANDO: Otoceratidae [1]; NAKAZAWA: L.
Tr. Kurotaki fauna (Shikoku) ; HIRANO: Biostrati. Jr. Toyora, I; MATSUMOTO: ColJignoniceratidae, V
ISHIBASHI: Up. Tr. Ceph. Tanoura(Kyushu); SATO: Bajoc. Amm. Kitakami; SUZUKI & SATO: Jr. Amm.
Toriashi [1]; SA TO: Amm. Toarcien
Saigon; NODA: Amm. (Berriasel/a)
Yamabu (Kyushu) ; SHIKAMA & SuzuKI : Choshi Cr. [J]; MATSUMOTO et al. :Cenomanian gaudryc. Amm.; *MATSUMOTO et al.: 2 small desmoc. Amm.
BAN DO: Otoceratidae & Ophiceratidae;
ISHIBASHI: Up. Tr. Amm. Okinawa,
II; HIRANO: Biostr. Jr. Toyora, II-III;
TAKAHASHI: Up. Jr.-L. Cr. Amm. Isokusa (Kitakami); OBATA: Pseudoleymeriella from Miyako; HASHIMOTO:
Hourcquia from Abeshinai (Hokkaido) ;*MATSUMOTO: Late Cr. Amm. (Palaeobiogeogr.); Vascoceratid; MATSUMOTO et al. : Shimanto Cr. fossils Kagoshima (Kyushu) [1]; *HAYAMI: Evolutionary interpret. biostrati. zones [1]
BANDO & SHIMOYAMA: Late Scyth.
Amm. Kitakami; KAPOOR & BANDO:
L. Tr. Kashimir; SATO: Jr. Amm.
Inuyama (central]apan) ; MATSUMOTO
in TAMURA et al.: Amm. (Eucalycoc.)
Mifune; MATSUMOTO (ed.): Palaeontology, II [1]-Asakura
BAN DO: Perm. Medlicottiidae; Subcolumbites; L. Tr. Amm. Kashimir;
ISHIBASHI: Up. Tr. Amm. Okinawa,
III; Tr. Amm. Indonesia & Malaysia;
SATO: Marine Jr. S.E. Asia (with listof Jr. Amm.) ; OBATA et al. : Cr. Choshi[1]; Alb. Amm. cent. Andes [1];OBATA: Diadochoceras, Miyako; *REYMENT: Reesidites; MATSUMOTO: Additional Acanthoceratids; *HIRANO:
Ontogeny of Gaudryceras tenuiliratum ;*T ANABE : Allometr. ontogeny & funct.
morpho of Otoscaphites puerculus;
MATSUMOTO & KAWANO: Pseudocalycoceras

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 97, pp. 7-21, pI. 1, April, 30, 1975

643. A FIND OF PSEUDOCALYCOCERSA FROM HOKKAIDO(STUDIES OF CRETACEOUS AMMONITES FROM HOKKAIDOAND SAGHALIEN-PART XXVII)TATSURO MATSUMOTO
Department of Geology, Kyushu University, Fukuoka 812

andTADASHI KAWANO
320 Tokiwa·machi, Tomatsu, Mikasa, Hokkaido 068-22:li:#ii~iJ' I? -/ "- - F"4'- i' '7 -1 :1 -I?: '7 .7-0);BJi!.: Pseudocalycoceras It 7 7J :/ l- -I?: '7 .7-f40) 1 NI, ...e, THOMEL (1969) iJ~:JIi!~ Ct-:o ~;;!:;:fl1!0) Ammonites harpax STOLICZKA It, -1:/ F". -<7l"7J'.7-7JJv· "'" '" 'Y:1 • 7'7:/ .7-mJlfill\t.r::c·tc~l?n~o THOMEL (1972) Itl'&J[(7'7:/ .7-mJIHiil~O):fl1!~\" <'0iJ,~ttL. "S'.t-:"f- ,,-.=.:./7 . 9='J1U.r::Clc t:5=f:fl1!iJ~~-t"~;: C ~fij:Jii Lt-:o {t!!.:1J:Ii: 7 -< ~ 7J ""('It, COBBAN & SCOTT (1972) iJ~*~O)~{7IJ~~tt Lt-:o lii'l t:~tc:li:w~O) ~*!5ljiJ'l?~ U' 7 :/","7-1 l- ~ fiiJ!IlfiJ~:j)!(~ L. t~*iJ;lj}f:9"e Ltdii5*, ;:;flit
Pseudocalycoceras O)IEf{7J]""('il;/), CiJ't:li:7 -< ~ 7J~0) P. dentonense tc~b6b-CJ[(\"tO)""('il; ~ ;: c iJ;.!JtiJ'--:d-: o *~O) B *tC:toV1" ~ It t:6b-C O)~~-C-il; ~ 0 t~*lt Am. harpaxO)~;;!:;.*~ • • C~;:c~il;~O)-C-,;:n~£.K, ;:O).lii'l~KAn~~~:fl1!~.~L.

C, Pseudocalycoceras ~:jl}~~-t" ~ *~It 7 '7 :/.7- -C-It -I?: / -<.=. 7 :/Jll!:l:flI\tc~-t" ~ c ~n -C \" ~ iJ~, ;ji:#ii~~O):fl1!lt Kanabiceras septemseriatum, Sumitomoceras faustum iCf¥.\",
Inoceramus labiatus I? C ~ t O)~ tf¥.? O)-C-, "f- "- - '" .=. 7 :/Jll!:TflI\O)riJ1lE1'iltt.r:::to~~-c-~t.r::\"o Jll!:J[(~.Et~Hcr~9~c t.r::'?-C\,'~-I?: / -<.=. 7:/ . "f- "- - "'.=. 7 :/m:w-O)~~cx;f.lttc
1}95lc-c, ~b6b-C~,*i*\,,:ftfl-""('il;~O)""(', ffifIi~~~.;z,.~ot~*Jif!~ ·1OJ!ilfIEiE.
0

genus and also for international corre·
lation of Cretaceous sequences that wegive a palaeontologic description of theammonite in this paper. Notes are also
given by one of us (T. M.) on the genus
Pseudocalycoceras. We then discuss age
correlation of the relevant strata.
Before going further we thank Messrs
Masanobu KIKUCHI and Tatsuo MURAMOTO who gave us valuable information.
Dr. Hiromichi HIRANO and Miss Mutsuko
HA Y ASH IDA assisted us in preparing theplate and typescript. Finally we aremuch indebted to Mr. C. W. WRIGHT for
critical reading of the first draft andIntroduction
In July 1972 one of us (T. K.) collected
an interesting ammonite from loco Ik
1038, Ikushumbets, Hokkaido. This was
so unfamiliar to Hokkaido that it wassent in 1973 to the other of us (T. M.)
for further study. As a result it is clearthat the specimen is an example of
Pseudocalycoceras THOMEL, 1969.
Although only one specimen is availa·
ble, the discovery is so important for
the evaluation of this recently established* Received June 28, 1974: read June 15,
1974 at Osaka.

7

8

Tatsuro MATSUMOTO and Tadashi KAWANO

giving unpublished
British example.

information on aNotes on Pseudocalycoceras(by Tatsuro MATSUMOTO)
The generic diagnosis originally given
by THOMEL (1969) and subsequently
followed by others (e. g. KENNEDY, 1971,
p. 81) is revised here in the light of aredefinition of the type·species and arevised list of species to be included in
the genus.
Genus Pseudocalycoceras THOMEL, 1969
Type-species :-Ammonites harpax
STOLICZKA, 1865.
Generic diagnosis: - Me diu m-s i zed,
moderately involute to rather evolute, notmarkedly compressed or depressed, with
flexuous to rursiradiate ribs, consistingof longer primaries and inserted orbranched secondaries, distinct' umbilical,
inner [i. e. lower] ventrolateral, outer[i. e. upper] ventrolateral and siphonal
tubercles. The outer ventrolateral andsiphonal tubercles are more or lessclavate and fairly closely spaced acrossa moderately rounded venter.
For most of the outer whorl the ribs

Near the end
_90"
-270°

Diameter
91. 5(1)74.5(1)are rursiradiate and comparatively coarse
and the umbilical tubercles are stronger
and may be twisted to S. Some of the, ribs may be accentuated, without forming
a tubercle, at the bending point on theflank.
On the last part of the adult bodychamber the ribs tend to be narrower
and less distant, the outer tubercles
weaken and are finally absorbed by anelevated rib and the umbilical tubercles
become bullate and weaker.
The suture is of Acanthoceras type andprobably varies to a considerable extent
between species.
Restudy of Pseudocalycoceras harpax:STOLICZKA (1865, p. 72) establishedAmmonites harpax on more than one
specimen. Of the two illustrated syntypes, the one figured in pL 39, fig. 1(GSI. 169), which was regarded by
STOLICZKA himself as representing a"regular or typical" form, is here designated as the lectotype. It came from acalcareous sandstone, west of Odium,near Moraviatoor, southern India.
On the basis of my observation of thisspecimen at Calcutta, notes are given
below, with a sketch (Text-fig. 1).
(1) The measurements of the lectotype
are as follows:

Umbilicus
27.5(.30)
20.5(.27)(2) The shell is moderately involute, withthe outer' whorl embracing the inner alittle further than the row of inner
ventrolateral tubercles. The umbilicus
is accordingly of moderate size, not exceeding 30 percent of the' entire shell
diameter.
(3) The whorl is somewhat higher thanbroad in the adult stage, although it may

Height38.0(.41)
32.5(.43)
23.5

Breadth33.5(.36)
29.7(.39)
22.5

B./H.
0.88
0.91
0.95

be only slightly so in immature stages.
It has nearly parallel and 'flattened
flanks, a moderately round arched venter,subrounded umbilical shoulder's and nearly vertical, partly overhanging, umbilicalwalls.
(4) There are numerous ribs, 38 on thelast entire whorl; long and short ones
as a rule alternate, though occasionally643.

Pseudocalycoceras from Hokkaido

Pseudocalycoceras
harpax (STOLICZKA).

Text·fig. 1.

Diagrammatic sketch of the lectotype, GSI.
169. Lateral (a) and frontal (b) views.
(T. M. de/in.)two shorter ribs are inserted. On thelast part (about 60') of the body-chamber
ribs are more crowded than on otherparts, numbering 16 On the last quarter
whorl. On the preceding half whorl, i. e.
the posterior part of the body chamber
and the last part of the septate whorl,
which is here called the adolescent stage
for convenience' sake, ribs are coarser
than on other parts, numbering 16 perhalf whorl at this stage. Contrary to
THOMEL'S description (1969, p. 650), ribs
never number 25 per whorl at any stageof this lectotype or in KOSSMA T's illustrated specimen.
(5) Ribs are somewhat prorsiradiate on
the inner part of the flank, then curve
backward, being more or less rursiradiateon the main outer part of the flank, andcross the venter with a considerable
elevation. At the adolescent stage theCOnvex curvature is strong, resulting inremarkable rursiradiate ribbing. In thelast part the curvature becomes gentle.
On the flank of the earlier stages theribs look somewhat flexuous.

9(6) In the adolescent part umbilicaltubercles are prominent and apparently
twisted. In the preceding part they areof moderate intensity. In the last part,i. e. on the anterior half of the bodywhorl, they are bullate and tend to be
weakened.
(7) In that last part the outer tubercles
are much weakened and finally disappear,
although the ribs are distinctly elevated.
Otherwise the five rows of outer tubercles
are prominent and clavate. They arenearly equidistant; the distance between
the siphonal tubercle and the outerventrolateral is slightly shorter than thatbetween the outer ventrolateral and theinner ventrOlateral, with a proportion of
about 10: 11 0. e. 5.0: 5.5 mm. at whorlheight=27 mm.).
(8) The suture illustrated by STOLICZKA(186;), pI. 39, fig. 1b) is essentially correct.
I do not know precisely the extent ofvanatIOn in P. harpax. The otherspecimen illustrated by STOLICZKA (1865,
pI. 18, fig. 2), which he regarded as acompressed variety of the same species,
was transferred by KossMA T (1897, p.
14) to Eucalyeoeeras pentagonum (JUKESBROWNE, 1896). This has recently been
accepted by KENNEDY (1971, p. 81) but
I think this assignment doubtful. I examined STOLICZKA'S original specimen,
GSI. 168, and observed that it is nqt
referable to E. pentagonum, because it
has somewhat rursiradiate ribs and distinctly clavate outer tubercles in fiverows, of which first the inner ventrolateraland then the siphonal tubercles disappear
before the outer ventrolateral, and because
ribs are not effaced at mid-flank. This
specimen might be a species of Euealycoeeras, allied to such species as E.
eollignoni (FABRE) (see THOMEL, 1972, p.
85, pI. 27, fig. 7), from the top of the
Cenomanian in the Maritime Alps, showingintermediate features between Eucaly-

10

Tatsuro MATSUMOTO and Tadashi KAWANO

coceras and Pseudocalycoceras.
KOSSMA T (1897) dealt with five specimens of P. harpax but did not mention
variation within the species. His illustrated specimen (KOSSMA T, 1897, p. 13,
pI. 4, fig. 2) seems to represent what I
call the adolescent stage. Its outer whorl
has somewhat coarser and more distantribs than the corresponding stage of thelectotype. Such a difference can well beconsidered to be within the extent ofvariation of the same species. Considerable variability is seen in a number ofillustrated specimens of P. harpax fromother areas (e. g. COLLIGNON, 1937, p. 33,
pI. 1, figs. 1-4; COLLIGNON, 1964, p. 145,
pI. 373, figs. 1620-1622, from Madagascar;
COLLIGNON, 1966, p. 30, pI. 13, from
Tarfaya, Morocco; THOMEL in PORTHAUL
et aI., 1966, p. 428, pI. 9, figs. 1-3; pI. 10,
figs. 1-2; THOMEL, 1972, p. 88, pI. 29,
fig. 3; pI. 30, figs. 10-11, pI. 31, figs. 1-5,
pI. 32, figs. 1-2, from southeast France).
Several subspecies were reported to occur
in the same zone of France. If the fossil
populations were examined more carefully, some of the subspecific names would
prove to be unnecessary.
SPecies to be referred to Pseudocalycoceras :-THOMEL (1972, p. 88) listed
seventeen species under the genus
Pseudocalycoceras.
It may indeed bedifficult to comment on all of them without seeing the original specimens, butsome species are better excluded fromthis genus. Certain other species should
be added to the list. The following is alist of species which are to be referred
to Pseudocalycoceras.
(1) Ammonites harpax STOLICZKA, 1865,
type-species (see above).
(2) Ammonites morpheus STOLICZKA, 1865
(p. 80, pI. 38, fig. 1), from southern India.
This was establised on two syntypes, but
the un illustrated one is missing. Therefore, the illustrated one (GSI. 167), which

I examined at Calcutta (Text-fig. 2), is
designated here as the lectotype. In
lateral view it does show the diagnostic
features of Pseudocalycoceras, but it isvery peculiar in that it has only two;instead of three, approximated rows ofventral clavi in addition to the tubercles
at the ventrolateral shoulders. Moreover,in a limited part (-260· to -300·) of its
outer whorl 0. e. the earlier half of theadolescent stage), a longer rib on theleft side joins a shorter one on the right.
These features suggest that it is amalformed shell.
C. W. WRIGHT reports (in iitt.) that
he has a specimen (19820) from Bed Cof the Cenomanian of the Devon, England,consisting of one third of a whorl corresponding to the last quarter of thepenultimate whorl and beginning of thelast whorl of the lectotype. It closely

Text-fig. 2. Pseudocalycoceras
morpheus (STOLICZKA).
Diagrammatic sketch of the lectotype, GSI.
167. Lateral view (a), whorl-section (b)and external suture (c) at S. (T. M. delin.)643.

Pseudocalycoceras from Hokkaido

resembles the lectotype except that theouter ventrolateral tubercles are muchfurther apart and between them there isa row of siphonal clavi; at the earliest
part of the fragment the siphonal tubercle
is as· strong as the outer ventrolateral,but by the end it has almost disappeared.
Pseudocalycoceras morpheus is allied toP. harpax, but is distinguished by its
broader whorl (B./H.=1.05 at diameter of
113 mm), wider umbilicus (32 percent of
diameter), stronger and coarser ribs
(numbering 14 per half whorl at theadolescent stage) and broader, subquadrate lateral lobe (L). The accentuated elevation of the longer ribs at thebending point is considerable in thelectotype of P. morpheus.
This species was reported to occur in
the Cenomanian (zone 5) of the Subalpines, southeast France, by THOMEL(1972, p. 91, pI. 32, figs. 3-4). His specimen is also characterized by four rowsof outer tubercles, with disappearance ofthe siphonal tubercle at an early stage.
(3) Acanthoceras barcousi JONES (1938, p.
117, pI. 6, figs. 2, 3, 8, 9) from the basal
part of the Eagle Ford Formation, Texas,
and the Indidura Formation of Coahuila,
Mexico. This is fairly similar to P.
morpheus, but its siphonal tubercles are
distinct and its ventrolateral tubercles
are less clavate and its ribs less flattened
than in the latter.
(4) Eucalycoceras dentonense MOREMAN(1942, p. 205, pI. 33, figs. 4, 5; text-fig. 2k),from the Britton Member of the Eagle
Ford Formation of Texas, and the basal
part of the Bridge Creek Limestone
Member of the Greenhorn Limestone,
Colorado (see COBBAN and SCOTT, 1972).
(4') Pseudocalycoceras sp. aff. P. dentonense(MOREMAN), from Hokkaido, described
below in this paper.
(5) Calycoceras alaouitense BASSE (1940,
p. 449, pI. 8, figs. 1, 4), from the11

Cenomanian of Syria. This is fairly
similar to Pseudocalycoceras dentonense,
but owing to the secondary deformationof the specimens exact comparison isdifficult. Another question is whether
Calycoceras paralaouitense BASSE (1940,
p. 449, pI. 7, fig. 4, pI. 8, figs. 2, 3; pI. 9,
fig. 3) and C. alaouitense from the same
locality are really different species ormerely polymorphic variation of one andthe same species. It is furthermore a
puzzle that this species of Pseudocalycoceras is recorded as occurring withMantelliceras couloni and two species ofAcompsoceras, which suggest Lower
Cenomanian.
(6) Pseudocalycoceras eguituriense THOMEL (1972, p. 92, pI. 29, figs. 6, 7, pI. 30,
fig. 7; pI. 31, fig. 6), from the Upper
Cenomanian of southeast France.
(7) Acanthoceras haugi PERVINQUIERE(1907, p. 270, pI. 14, fig. 1), from theUpper Cenomanian of Tunisia. This is
closely allied to P. barcusi (JONES), although the rursiradiate ribbing is not somarked as in the latter. It has beenreported to occur also in the Upper
Cenomanian of the Middle East, Madagascar and southeast France (at theboundary of zones 5 and 6). THOMEL(1972, p. 96) proposed subgenus Haugiceras
for this species.
The specimens which were describedunder the name of P. (H.) rob us tum
THOMEL (1972, p. 98, pI. 47, figs. 6-7)
could be within the variation of P. haugi
in view of their resemblance and theoccurrence at the same horizon (boundaryof zones 5 and 6) in southeast France.
THOMEL'S interpretation of Pseudocalycoceras seems to me too comprehensive.
COBBAN and SCOTT (1972, p. 63) havepointed out that Barroisiceras trinodosum
MOREMAN (1942, p. 212, pI. 33, figs. 1-2;
text-fig. 2a) and B. brittonense MOREMAN(1942, p. 212, pI. 33, fig. 3; text-fig. 2b),

12

Tatsuro MATSUMOTO and Tadashi KAWANO

assigned to Pseudocalycoceras by THOMEL,
are abnormally formed specimens of
Metoicoceras whitei HYATT. I consider
it possible that Pseudocalycoceras planum
THOMEL (1972, p. 93, pI. 30, figs. 1-6)
could be grouped with" Jeanrogericeras ?
sornayi THOMEL (in PORT HAUL T et a!.,1966, p. 431, pI. 11, figs. 1-3) in Thomelites
WRIGHT and KENNEDY, 1973, of theMetoicoceratinae.
Protacanthoceras
collignoni
FABRE(1940, p. 225, pI. 7, fig. 7, 8) could be referable to Pseudocalycoceras as KENNEDY(1971, p. 97) considered. I would provisionally assign it to Eucalycoceras, as
THOMEL (1972, p. 85) did, although it isatypical, having mixed characters of thetwo genera.
I hesitate to ascribe Protacanthoceras
angolaense SPATH (1931, p. 316), P.
batnense COLLIGNON (1937, p. 36, pI. 2,
fig. 3), P. jullieni COLLIGNON (1937, p. 36,
pI. 2, fig. 1; pI. 8, fig. 3), and P. judaicum(T AUBENHAUS) (1920, p. 13, pI. 3, fig. 1;
A VNIMELECH and SHORESH, 1965, p. 531,
pI. 15, fig. 1) to Pseudocalycoceras, although they differ from typical speciesof Protacanthoceras.
I have no comments on Protacanthoceras
fiandrini THOMEL (1966, in PORTHAUL T
et a!., p. 430, pI. 10, figs. 3-5), Pseudocalycoceras pseudo-orbignyi THOMEL (1972, p.
95, pI. 29, figs. 1-2) and Pseudocalycoceras
dromense THOMEL (1972, p. 94, pI. 30,
figs. 8-9). If they are to be referred to
Pseudocalycoceras, they are all atypical.
Comparison and affinity: - Immatureshells of Pseudocalycoceras are somewhat
similar to Protacanthoceras SPATH, 1923.
The latter genus is represented by Ammonites bunburianus SHARPE, 1853, typespecies, and other allied species, mostly
based on small specimens. COLLIGNON
suggested (see THOMEL, 1972, p. 99) thatthe two nominal genera might represent
a sexual dimorphism, microform Prota-

canthoceras and macroform Pseudocalycoceras. The available evidence is yet
insufficient. COBBAN and SCOTT (1972)
have shown specimens of various size inPseudocalycoceras dentonense, which do
not seem to support the above interpretation. In the specimen from Hokkaido
described in this paper as P. sp. aff. P.
dentonense the immature whorl has rather
flattened flanks and somewhat, but not
much, closely spaced three rows ofventral tubercles, but the ventral tubercles are not so distinctly clavate as inProtacanthoceras.
In the visible earlier part of the lectotype of Pseudocalycoceras harpax theventral tubercles are somewhat clavate
but not so closely spaced and the venter
is not so high and narrow as in typical
species of Protacanthoceras. KENNEDY(1971, p. 96) has recently given a revised
diagnosis of Protacanthoceras. While thedifference is not great in immature shellsof Pseudocalycoceras, distinction in theadult shells is unmistakable.
WRIGHT and KENNEDY (1973, p. 26)
suggest that Protacanthoceras may bemicromorphs of Thomelites.
Pseudocalycoceras resembles Eucalycoceras SPATH, 1923 (see redefinition by
KENNEDY, 1971, p. 80), in the fairly
closely spaced ventral rows of tubercles
which may disappear on the last part ofthe body-whorl, but is distinguished byits less involution, wider umbilicus, lesscompressed or broader whorl, less numerous and more distant ribs, which arecharacteristically rursiradiate on theouter whorl. In the typical species of
Eucalycoceras ribs are rectiradiate andeven somewhat projected forward on theventral part. Exceptional examples inthis respect are Eucalycoceras collignoni(FABRE, 1940) (see THOMEL, 1972, p. 85,
pI. 27, fig. 7), from the Upper Cenomanianof France, and its allied species from643.

Pseudocalycoceras from Hokkaido

India [=Ammonites harpax STOLICZKA,
1865, p. 72 (pars.), pI. 38, fig. 2J, in which
the ribs are somewhat curved backward
on the flank. In other respects, howeverthese species are closer to the typical
species of Eucalycoceras than to those of

Pseudocalycoceras.
Pseudocalycoceras is apparently similar
to Paracalycoceras SPATH, 1925 (see recent
redefinition by KENNEDY, 1971, p. 79) inthe strong, rursiradiate ribbing on theadult whorl. Only an incipient siphonal
tubercle is discernible in the immatureshell of Paracalycoceras, which shows" Submantelliceras" like aspect. Paracalycoceras has been known in the Lower
Cenomanian and there are no connecting
forms between the two genera. Probably
the resemblance of the two genera isheterochronous homoeomorphy within thesame family.
In THOMEL'S (1972, p. 199) study of theFrench material Pseudocalycoceras has
been endowed with an important positionin the phylogeny of the Acanthoceratidae,
a starting point were Metoicoceratinae
and Mammitinae are going to branchapart from the Mantelliceratinae. Thisis considerably different from the previ·
ous view (e. g. REYMENT, 1955; WRIGHT,
1957) in which the origins of Metoicoceratinae and Mammitinae were ascribedto Acanthoceratinae.
THOMEL (1972)
furthermore interpreted P s e u doc a I ycoceras, Protacanthoceras and Eucalycoceras as being derived in common fromthe group of Calycoceras gentoni (subgenus Gentoniceras THOMEL, 1972), regarding all of them as later members of
the Mantelliceratinae. KENNEDY (1971),
however, keeps Protacanthoceras in Acanthoceratinae. As I have now no goodevidence to discuss the phylogeny, I
merely draw attention to the problem.

13

Description of a species
from Hokkaido(by Tatsuro MATSUMOTO and
Masashi KAWANO)
Family Acanthoceratidae
DE GROSSOUVRE, 1894
Genus Pseudocalycoceras
THOMEL, 1969

Pseudocalycoceras sp. aff. P.
dentonense (MOREMAN)
PI. 1, Fig. 1; Text-fig. 3Compare :1927. Acanthoceras sp. A, MOREMAX, Jour.
Paieont., vol. 1, p. 95, pI. 15, fig. 2.
1942. Eucaiycoceras dentonense MOREMAN,
Jour. Paieont., vol. 16, p. 205, pI. 33,
figs. 4, 5; text.fig. 2k.
1942. Eucalycoceras indianense MORE:"IA:\,
Jour. Paleont., vol. 16, p. 206, pI. 33,
figs. 9, 10; text.fig. 21.
1942. Eucaiycoceras lewisvillense MOREMAN,
Jour. Paieont., vol. 16, p. 206, pI. 33,
figs. 6, 7; text·figs. 2n, u.
1973. Pseudocaiycoceras dentonense, COBBAN
and SCOTT, 1972, U. S. Ceoi. Surv. Prof.
Paper 645, p. 63, pI. 13, figs. 11-29; pI.
15, figs. 1-7, 10-13 (with a complete
list of synonymy).

Material :-A specimen of T. KAWANO'S
collection from loco Ik 1038, Ikushumbets,
represented by a fairly well preserved
internal mould.
Description :-The ventral portion of
the adoral part of the body chamber ismissing. If it was preserved, the shellwould be about 90 mm in diameter. Fromvarious aspects the specimen is judged
as representing an adult shell.
The shell is considerably evolute, withthe umbilical seam of the outer whorl
running along the row of inner ventrolateral tubercles of the next inner whorl.
The whorls grow at a moderate rate,

14

Tatsuro MATSUMOTO and Tadashi KAWANO

encircling an umbilicus of moderate size,
31 to 32 percent of the entire shell
diameter.
The septate whorl is a little higher
than broad and has rather flattened,roughly parallel flanks; the body chamberis nearly as high as broad or only veryslightly higher than broad, having gently
inflated flanks. The venter is arched andmoderately rounded; the umbilical wallis steep and nearly vertical, the umbilicalshoulder is subangular on the main partand subrounded on the last part of the
body chamber.
The ornament of the "adolescentstage ", which occupies about a half
whorl, consisting of the last part of thephragmocone and the posterior part ofthe body chamber, with diameters from45 to 65 mm, is most diagnostic. At thisstage the ribs are strong and more orless rursiradiate; some of them are somewhat prorsiradiate on the inner part of
the flank and then abruptly bent backward, being accentuated at the bending
point, if not forming a tubercle. Bifurcated ribs and a simple one as a rulealternate. The bifurcation occurs at ornear the very prominent, apparently
backward twisted umbilical tubercle,
whereas some of the simple ribs have aweaker umbilical tubercle. In this half
whorl there are 12 ribs, separated bysomewhat broader inters paces. The outer
tubercles are moderately prominent; thesiphonal and the outer ventrolateral ones
clavate, equally strong and considerably
approximated, forming three rows on theventer. The inner ventrolateral tubercle
is nodate and more distant from the outerventrolateral tubercle than the siphonalone.
On the earlier whorl the ribs are
weaker, nearly rectiradiate or slightly
prorsiradiate, and somewhat flexuous on
the flank. The umbilical tubercles arerather bullate; the outer tubercles are
distinct, the ventral three fairly approximated but not so distinctly clavate as inlater stages. Shorter, inserted ribs haveno umbilical tubercles. Ribs number 12
or 13 per half whorl.
The body chamber occupies at least
about half a whorl. On its earlier part(for about 60· or 1/6 whor!), the ornament of the" adolescent type" continues,
but the outer tubercles in five rows tend
to be gradually weakened. On the restof the body chamber the ribs are mostly
simple, equally long, fairly elevated but
gradually becoming narrower than theribs of the preceding stage. They are
rather gently rursiradiate on the flankand cross the venter, where tubercles
are obsolete. The umbilical tubercles
are also weakened but remain as bullae
at the shoulder. A weak extension of
the rib on the inclined umbilical wallruns obliquely forward from the umbilicalbulla to the umbilical seam. The intervals between the ribs are broader than
the ribs themselves, but tend to decrease
their breadth slightly towards the aperture. A shorter rib may occasionally beintercalated; this feature is uncertain
because the last part of the specimen isincompletely preserved. There are 13(+ I?) ribs on the body chamber. Someof the ribs are slightly accentuated on
the middle of the flank.
Sutures are of general acanthoceratid
type. The features which may be characteristic of this species are (1) deepnessof E, being twice as deep as L, (2)broadness of the first lateral saddle,
which is asymmetrically bipartite, (3) Lbeing somewhat narrowed at the middleof its stem, with lower lateral branches
expanding on both sides, and (4) the
second lateral saddle (between Land U2)
being higher but much narrower than(about a half as narrow as) the first.

643.

Pseudocalycoceras from Hokkaido

15

Measurements :Specimen
DiameterUmbilicus
HeightBreadthB./H.
(1) Hokkaido
ca 90(?)
27.6(.30)
28 (.31)"(_70°)
70.0
22.8(.32)
28.2(.40)
27.4(.39)
0.97"( -160°)
60.5
19.0(.31)
26.0(.42)
24.0(.39)
0.92(2) BEG. 19804
33.0
31. 5
0.95
(3) BEG. 19805
2;:;.023.0
0.92(1) this specimen, (2) holotype of E. dentonense, (3) holotype of E. indianense.

Text-fig. 3. Pseudocalycoceras sp.
aff. P. dentonense (MOREMA!\")
External suture at whorl-height=21 mm.
The same specimen of KAWANO'S Collection
as illustrated in PI. 1, Fig. la-e.

Comparison :-The described specimen
from Hokkaido is very close to the holotype and other specimens of Pseudocalycoceras dentonense (MOREMAN), redescribed by COBBAN and SCOTT (1972),
from the Britton Clay of the Eagle Ford
Shale of Texas and the Bridge Creek
Limestone Member of the Greenhorn
Limestone of Colorado. We would agreewith COBBAN and SCOTT in admitting acertain extent of variation in shell-form
and ornamentation of P. dentonense andin regarding the types of MOREMAN'S Eucalycoceras indianense and E.lewisvillense
as specifically identical with P. dentonense. In fact the later half of thelast whorl of our specimen is very close
to the holotype (BEG. 19804) of Eucalycoceras dentonense MOREMAN and theearlier half to that (BEG. 19805) of E.
indianense.
COBBAN and SCOTT report that ribs
number 15-21 per half whorl. If this was
the real extent of variation in rib density,

our specimen would be outside it, because
ribs number 12 or 13 per half whorl inours. The difference is, however, small
and we do not know the extent of variation in our population. Among thespecimens illustrated by COBBAN and
SCOTT, that of pI. 15, figs. 4-6 (USNM
163923) is the closest to our specimen.
It seems to have 26 ribs in the last full
whorl, showing almost the same rib
density as ours. In spite of a considerable number of specimens from the UnitedStates no clear illustration of suture is available. The suture of the holotype is imperfectly preserved, although MOREMAN
described it at some length. COBBAN and
SCOTT reported that only parts of. thesuture were visible. Our specimen does
show diagnostic features in suture.
Whether the same features are maintainedin American examples of P. dentonense or
not is a point to be worked out.
In the above circumstances, we have tocall our specimen for the time being
Pseudocalycoceras sp. aff. P. dentonense(MOREMAN); the present specimen may
represent a geographical subspecies of P.
dentonense.
Our specimen is somewhat similar tothe lectotype of Ammonites harpax
STOLICZKA (1865), defined above, but has
a broader and more inflated body-whorl,
more distant ribs and nodate, instead ofclavate, inner ventrolateral tubercles
which are more distant from the outerones. Even if we admit a certain extent
of variability, P. dentonense is distinguish-

16

Tatsuro MATSUMOTO and Tadashi KAWANO

able from P. harpax in that in the former
the shell is more evolute and more widely
umbilicate, the three rows of ventral,clavate tubercles are more approximatedand the inner ventrolateral tubercles arenodate, instead of clavate, and moredistant from the inner ventral ones thanin the latter. Probably the former hason the average less numerous ribs thanthe latter, although the range of rib
density may overlap between the two
species. Incidentally the sutural patternof P. harpax, as illustrated by STOLICZKA(1865, pI. 39, fig. Ib) and COLLIGNON(1937, pI. 1, figs. 2, 4; pI. 8, figs. 1, 2), isessentially similar to that of our specimen, especially with respect to the character of the first lateral lobe.
Occurrence :-Loc. Ik 1038, a cliff on
the right side of the main stream of the
Ikushumbets (see map in MATSUMOTO,
1965, fig. 2), where uppermost part of the
middle siltstone member (unit IIc) of
Mikasa Formation is exposed (see columnar section in MATSUMOTO, 1965, fig.
4). The described ammonite was contained in a calcareous nodule which was
found at a horizon about 8 m stratigraphically below the green sandstone at
the base of the Upper member (unit lId),
as shown in a sketch of Fig. 4. It wascollected and developed by T. KAWANO.
The associated ammonites in the same
nodule are a fragment of Eucalycoceras (?)
sp. aff. E. collignoni (FABRE), Allocriocerassp., Sciponoceras sp. and Scaphites sp.
Remarks :-In addition to the above
described specimen there are three otherincompletely preserved ones from the
Ikushumbets area which may be ofidentical species. One is GK. H5692, collected by T. MURAMOTO from loco Ik
1434p, Kami-ichino-sawa, a tributary of
the Ikushumbets, which is somewhat
deformed but shows essentially the samecharacteristic features as the above. Twoothers in the collection of Hokkaido
University, No. 12434 and 12435, weretentatively described under Eucalycoceras
sp. by MATSUMOTO, SAITO and FUKADA(1957, p. 38, pI. 11, fig. 2; text-fig. 14)
but now seem to be better transferredto the present species, although they are
too poorly preserved for a definite conclusion.

Correlation problem
The siltstone of about 15 meters which
occupies the uppermost part of unit IIc,
immediately below the green sandstone
at the base of unit lId, is expoed at loco
Ik 1038 and Ik 987, across the maincourse of the Ikushumbets River. In thispart of the Ikushumbets sequence Kanabiceras septemseriatum and Sumitomoceras
faustum occur exclusively and are associated with Sciponoceras kossmati,
Allocrioceras sp. and other species ofammonites. It represents the Zone of
Kanabiceras septemseriatwn which can betraced laterally in the Ikushumbets area.
In some previous papers (e. g. MATSUMOTO, 1959a, p. 65 ; MATSUMOTO et al.

Text-fig. 4. Sketch of the exposure
at loc. Ik 1038.

SS. Green sandstone at the base of Member
IId; MS. mudstone, containing calcareous
nodules, upper part of Member IIc; x A
nodle from which the described specimenof Pseudocaiycoceras sp. aft. P. dentonense
was found; F. Fault. (T. M. deiin.)

643.

Pseudocalycoceras from Hokkaido

1969, p. 289) this zone was correlated withLower Turonian, since Kanabiceras
septemseriatum occurs characteristicallyin the zone of Sciponoceras gracile of the
Gulf Coast and the Western Interior of
the United States, which, in turn, hadbeen assigned to Lower Turonian (MOREMAN, 1942; COBBAN and REESIDE, 1952).
In the recent paper of COBBAN and SCOTT.
1972, the Cenomanian-Turonian boundary
is put, though with a query, between thezone of Sciponoceras gracile and that of
Watinoceras coloradoense. One of thereasons of this assignment by theseauthors is the frequent occurrence ofPseudocalycoceras dentonense in the zoneof Sciponoceras gracile. In fact many
species of Pseudocalycoceras have beenreported to occur in the Upper Cenomanian of southeast France, mostly in thehighest zone 6 and some in the subjacentzone 5 (THOMEL, 1972), but no example
of P. dentonense has been found there.
In the type Cenomanian of Sarthe,
northern France, no species of Pseudocalycoceras was indicated in HANCOCK'S(1960) and WRIGHT and KENNEDY'S (in]UIGNET et aI., 1973) reliable lists ofUpper Cenomanian, although there seems
to be a certain thickness of strata without ammonites near the CenomanianTuronian boundary.
KENNEDY (1971) has recently shown afine scheme of ammonite sequence in the
Cenomanian Lower Chalk of southern
England. In spite of plentiful illustrationof acanthoceratid species, no example of
Pseudocalycoceras was shown in this
British sequence. However, as recorded
above (p. 10), C. W. WRIGHT reports
Pseudocalycoceras ct. morpheus from
Devon Bed C. It is noted that KENNEDY(1971, p. 12;:;) is inclined to draw the baseof the Turonian stage at the base of theMammites nodosoides-Mytiloides labiatus
Zone. In other words, the Scipolloceras

17

gracile-Metoicoceras whitei Zone, theplenus Marls and those parts of the
Middle Chalk below the appearance ofMammites and Mytiloides labiatus, yielding Sciponoceras gracile, Kanabiceras andNeocardioceras should be, according tohim, considered Upper Cenomanian. It
is, however, difficult to understand, for
us who are unfamiliar with the detailsof the British field evidence, that thesame author listed (KENNEDY, 1971, p.
103) as an ammonite assemblage of the
Middle Chalk (lower part) Manzmites
nodosoides, .M. spp., Metasigaloceras rusticum and Fagesia pachydiscoides, together
with Sciponoceras gracile, Kanabiceras
sp. Watinoceras sp. and. N eocardioceras
sp. This" assemblage" must be a mixed
list of ammonite species from at least
two zones; otherwise KENNEDY'S conclusion (in p. 125) would be inconsistent
with his explanation of the faunalsequence (in p. 103).
Regarding the Cenomanian-Turonianboundary in the type sequence of theMans (Sarthe) area, France, ]UIGNET,KENNEDY and WRIGHT (1973) have recently presented a result of their valuable
work with the following conclusion: (a)D'ORBIGNY'S base of Turonian must be
above the Metoicoceras Zones and at thebase of l'vfammites nodosoides-Inoceramus
labiatus Zone; (b) it is not yet clear inwhich zone-or which stage-the Neocardioceras juddi and Watinoceras faunasshould be placed.
So far as the available information from
North America is concerned, species of
W atinoceras' are characteristic of Lower
Turonian. Sumitomoceras faustum, which
occurs in the Zone of Kanabiceras septe7llseriatum of the Ikushumbets sequence, isclosely allied to Sumitomoceras [Watilloceras?J amudariense, from the Lower
Turonian of Turkestan (ARKHANGUELSKY,
1916). As has already been pointed out

18

Tatsuro MATSUMOTO and Tadashi KAWANO(see MATSUMOTO et aI., 1969, p. 281),
Sumitomoceras and Watinoceras are so to
speak in a sisterhood relationship. In
the sequence of England, as described by
KENNEDY, Sumitomoceras spp. are listed,
together with Kanabiceras sp. and othersin his Zone of Metoicoceras gourdoni and
Watinoceras sp., Kanabiceras sp., Neocardioceras sp., etc. in his list of Middle
Chalk (lower part). Thus, in the British
sequence, Watinoceras and Sumitomoceras
begin to appear in Upper Cenomanian, if
we follow KENNEDY'S conclusion of correlation. Anyhow, we are anxious toknow what kinds of Sumitomoceras andWatinoceras are found in which zones inEngland.
C. W. WRIGHT'S (in litt., 20 April, 1974)
provisional view at present is that the
Neocardioceras- Watinoceras - 5 u mit 0 m 0ceras horizons should be treated as basal
Turonian. Watinoceras is very closely
related, with many transitional forms, toMammites. Sumitomoceras, however, mayalso really occur with Metoicoceras inEngland.
In the sequence of Colorado studied
by COBBAN and SCOTT (1972) Kanabiceras
puebloense occurs in the Zone of Mammites
nodosoides, unmistakable Lower Turonian,which is well distinguishable from K.
septemseriatum of the underlying zone.
Thus Kanabiceras passes across the
Cenomanian-Turonian boundary in North
America. Weare again anxious to knowwhat kinds of Kanabiceras are found in
the British sequence.
Although the specimen is fragmentary,
an ammonite referable to Eucalycoceras(?) sp. aff. E. collignoni (FABRE) was
found in the same nodule as Pseudocalycoceras sp. aff. P. dentonrmse at loco Ik
1038. This could be reckoned as evidence
favouring the correlation with Upper
Cenomanian, but the identification is notconvincing. On the other hand, the oc-

currence of Puzosia sp. aff. P. intermedia
orientale MATSUMOTO (PI. 1, Fig. 2),
Gaudryceras sp. aff. G. varagurense (KossMAT) (PI. 1, Fig. 3) and Zelandites kawanoi(JIMBO) (all collected by T. KAWANO)
from the same locality Ok 1038) may berather suggestive of a Turonian age,although these species may be longranging.
Sciponoceras kossmati (NOWAK) occurs
fairly commonly in the same Zone of
Kanabiceras septemseriatum and also immediately subjacent parts on the exposures along the Ikushumbets River(MATSUMOTO and OBATA, 1963). In Hokkaido fossils of the same species wereobtained at loco R 117 of the Kotanbetsu
area in a musdtone unit from which
Inoceramus (Mytiloides) labiatus wasfound (at loco R 114) (see MATSUMOTO
and OKADA, 1973, p. 285, figs. 7, 8) andalso at loco Y552a of the Shuyubari area
in unit IIh above which (i. e. in unit IIj)
Calycoceras orientale was found. Thus,
the available evidence in Hokkaido showsthat S. kossmati ranges from Middle
Cenomanian to Lower Turonian. The
holotype of S. kossmati came from thelower Trichinopoly Group (probably
Lower Turonian) of India. Examples ofthe same species were recorded from
California (MATSUMOTO, 1959b, p. 106).
At one of the localities in California (i. e.
CAS. 33719) S. kossmati is associated with
Kanabiceras septemseriatum and Inoceramus (Mytiloides) d. labiatus (MATSUMOTO, 1959c, p. 102).
Allocriocerassp. and Desmoceras (?) sp.
are associated with Kanabiceras septemseriatum and Pseudocalycoceras aff. dentonense in the Ikushumbets area. The
former is represented. by incomplete,fragmentary specimens and the latter bysomewhat deformed specimens. We haveto search for more and better specimens
for the exact identification.

643.

Pseudocalycoceras from Hokkaido

The associated Inoceramus resembles
and could be identified with 1. (Mytiloides)
labiatus, but a careful work is needed forthis sort of highly variable bivalve. In
this connexion we are again anxious toknow what kind of Inoceramus Pictus s. 1.
occurs in the Zone of Sciponoceras gracileof North America.
A large sized species of Inoceramus
which can be comparable with I. pennatulus PERGAMENT occur commonly inthe main part of the siltstone of unit IIc
immediately below the Zone of K. septemseriatum in the Ikushumbets sequence.
In this part of IIc an example of Calycoceras d. naviculare was obtained by
OMORI (in IKEGAMI and OMORI, 1957, pI.
7, fig. la, b) from his loco Bll, about 73
m in distance (along a water supply
channel) westward from the exposure of
the green sandstone at the base of lId.
This indicates unmistakably Upper Cenomanian. In the lower part of unit lId,
which is composed of sandstone andsandy siltstone with some conglomerate,
ammonites are very few and bivalvesbelonging to Aphrodina, Glycymeris andtrigonians occur at several horizons.
Inoceramus hobetsensis begins to appear
in the middle part of lId, which indicates,
together with Collignoniceras woolgari,
Middle Turonian.
To sum up the present circumstances,it has become possible that the Zone of
Kanabiceras septemseriatum in thesequence of Hokkaido might be assigned
to the uppermost Cenomanian in termsof the international scale, although theprevious assignment of the Lower
Turonian could still remain as anotheralternative. It is emphasized that internationally cooperative work is keenly
required for the final solution of thecorrelation problem.

19

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Tatsuro MATSUMOTO and Tadashi KAWANO

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Explanation of Plate 1
Fig. 1. Pseudocalycoceras sp. aff. P. dentonense (MOREMAN) ........................ Page 13
KAWANO Collection, from loc, Ik 1038, uppermost part of Member lIe of the Mikasa
Formation, Ikushumbets area. Lateral (a) and ventral (b) views, slightly enlarged(x 1.1) ; diagrammatic costal whorl-section at each 90· (c-e) , xL
Fig. 2. Puzosia sp. aff. P. intermedia orientale MATSUMOTO ........................ Page 18
KAWANO Collection, from loco Ik 1038, lateral view, xL
Fig. 3. Caudryceras sp. aff. C. varagurense (KOSSMAT) .............................. Page 18
KAWANO Collection, from loc. Ik 1038, lateral view, xL
Photos by H. HIRANO, without whitening. Figs. 1c-e T. M. delin.

MATSUMOTO and J{AW ANO .'Pseudocalycoceras

ld

Plate 1

le

643.

Pseudocalycoceras from Hokkaido

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~ .~

lJlj

J:-O)fR
i1 :IT }]IJ

21

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Treatise on Invertebrate Paleontology,
Part L, Mollusca, Cephalopoda, Ammonoidea, p. L1-L490, Geol. Soc. Amer. &Univ. Kansas Press.
- - and KENNEDY, W. J. (1973): Paleontologie systematique.
In JUIGNET, P.,
KENNEDY, W. J. and WRIGHT, C. W.: Lalimite Cenomanien-Turonien dans laregion du Mans (Sarthe): Stratigraphie
et paleontologie. Ann. Pateont. (Invert.),vol. 59, no. 2, p. 226-242, pis. 1-3.
P. S.

This work has been done wi thin theframework of the IGCP project entitled"Mid-Cretaceous Erents".

MikasaShuyubari

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 97, pp. 22-31, April, 30, 1975

644. DISCOVERY OF LATE PERMIAN ARAXOCERAS FROM
THE TOYOMA FORMATION IN THE KITAKAMIMASSIF, NORTHEAST JAPAN*
MASAFUMI MURATA
Institute of Geology and Paleontology,
Tohoku University, Sendai 980

and
YUH BANDO
Department of Geology, Faculty of Education,
Kagawa University, Takamatsu 760~t;J::!1f:l1!!ff*~ J: ~ "lvA~~M Araxoceras 0)3£~: '8~!Jit*atl1);<lq~:IHT~~$:~t;:.

7t::t1l"t"Qff*~J:~. 7:/';::71 r Araxocerassp. iJ~3£~~.nt.:o .i!iHI:l~*I'tl001*<:. 'J'~O)? k.~f?~)ilil't.lltifcl't"'k.tJ:"'iJ~. ?f.~0)~111'tJ: <~f?~.n, I=(:tlErrg§1l§iO)~**~

O)~~~liR~J: ~ga~~.nt.: Araxoceras kiangsiense CHAO cMW"t"Q o Hll±l:l1!!,¢'U't:/&rfIB r !! 7 ;r..*~~~O)m~:I1!!J: ~ jlkiJi:"t" QltliJi-c, ~li!li~£.lltO)~ff-ftiID J: ~ 15m rul.l;:.i6
Q o ff*~O):/&JliO){t;fi~{ft~B':JliJf~*S*t;:.t;t? c, 3:l<f?"t" Q{t;fiiJ' I? Araxoceras Hll±l~i\§1'tff*~l=(:tfIBO) Palaeoneilo ogachiensis.Phestia kon'noi (MS) 1!ft;:.i6t.: Qo Araxoceras
1'1 r!! 7;r..*[lWMO) Otoceras t;:'*$ti1t{t;"t"Q~O)-C, 1=(:t1E0)1:!:iJ'Yjl0)7Iv';( =-7tlJ:lF1'7 :/O):XIV 7..,.. 1 '7 :/l=(:tfIBO)-!f!T p ;r..!1f1l1RiJ' 1?¥IH!f~.n, 7 -7 .f ;r..$:~0)" Iv A *[l ~MDzhulfian Stage ~~11-?"1" Qo ff*lIl=(:t$ J: ~ Araxoceras iJtHll±l 1..... -to) ~*iJ~~5E 1....
t.:~ cl't, *~tJ:~~~~"'?ot-J"lHiEJt· ~JI!:?ti~the Toyoma Formation to the Late
Permian age, on the basis of its stratigraphical position and the geological ageof the underlying formations, because of
the lack of fossils.
In the present article the writers describe a D zhulfian ammonoid, Araxoceras,collected from the Toyama Formationand stress its stratigraphical significance.
The writers offer their cordial thanks
here to Dr. Kotara HATAI, Professor
Emeritus of Tohoku University, and to
Dr. Yoshio ONUKI, Hase Geological Survey
Office, Sendai, for their kind guidance

Introduction and Acknowledgments
The Toyoma Formation, representing
the upper part of the Permian System inthe southern part of the Kitakami Massif,
consists mainly of black slate of about
1,700 meters in thickness. In spite of
the stratigraphical and paleontologicalstudies by many authors for many yeras,
no fossils useful for dating the formation
have been found. HANZAWA and MURATA(1963) and MURATA (1964, 1969) assigned* Received Oct. 30, 1974: read Oct. 3, 1973
at Tokyo.
22

644.

Late Permian Araxoceras from Toyoma Formation

and advice to this study. The writers
also express their sincere thanks to Professor Keiji NAKAZA w A, Kyoto University,and to Associate Professor Ken-ichi
ISHII, Osaka City University, for theiradvice and encouragement. The present
authors are indebted to the member of
the Permo-Triassic Working Group whoare concentrating on the Lower Himalayan Belt in a comparative study with
the Permian ammonoids from Kashmir ofIndia and from Iran. The writers' sincere
thanks are extended to Dr. Hushang
T ARAZ and Mr. Farrock GOLSHAN I of
the Geological Survey of Iran, for theirkind help during the field work in Iran,in 1969 and 1972.

Stratigraphical Note of the
Toyoma Formation at theAmmonoid Locality

The Toyoma Formation was proposedby MABUTI (1932, MS) for a thick clay
slate formation, which is superposed with
conformity upon the Yamazaki Conglomerate, exposed in the vicinity of Kitazawa, Toyoma-cho, Tome-gun" .. Miyagi
Prefecture. In the Kitakami Massif, theToyoma Formation is developed in six
separate areas, and shows rather uniform
lithological facies, consisting of thickblack slate intercalated with medium- tofine-grained sandstone layers and small
lenses of pebbly conglomerate in the lower
part. The Toyoma Formation is covered
with distinct unconformity by the
Scythian Hiraiso Formation. 'Consequently, the thickness of the Toyoma Formaton varies in different areas due tothe pre-Triassic erosion. In the typearea, this formation is 750 meters thick,and the maximum thickness attains 1,700
meters in the Utatsu Area.
The Toyoma Formation in the southern

23part of the Kitakami Massif is almost
barren of fossils. However, in the pastnearly fifty years some fossils were foundsporadically from the formation, and werelisted by MABUTI and NODA (1934), INAI
and TAKAHASHI (1940), SHIIDA (1940),
CHISAKA (1935), ONUKI et al. (1960), UEDA
(1963) and SATO (1969). Some of thefossils were described by HA YASAKA(1924, 1967), SUGIYAMA (1942), KOBAYASHI(1945), MURATA (1967, 1969) and NAKAZAWA and NEWELL (1968).
Recently, the senior writer was successful in working out a biostratigraphical subdivision of the Toyoma Formation
as follows:*
Kitakamispira hanzawai (MS)-Nuculopsis mabutii (MS) zone, Palaeoneiloogachiensis-Phestia kon'noi (MS) zone,
and Euphemitopsis kitakamiensisAstartella toyomensis zone.
The lower fossil zone is defined by thestratigraphic range of Euphemitopsis
kitakamiensis MURATA and Astartella
toyomensis NAKAZAWA and NEWELL.
This zone can be confirmed in almost allof the six areas. It corresponds to thelower of the Toyoma Formation, fromthe base up to about 500 meters. In the
Kitakami Massif, Lepidolina multiseptata(DEPRAT) and L. lwmaensis KANMERA
range up to just below the Euphemitopsis
kitakamiensis- Astartella toyomensis zone
as shown in Fig. 3. The middle fossil
zone is defined by the range of Palaeoneiloogachiensis HA YASAKA and Phestia kon'noi MURATA (MS). It is about 500 to
600 meters thick uniformly, and is widelydistributed except for the Karakuwa Area.
This fossil zone corresponds to the middle
part of the Toyoma Formation, however,the upper part of the formation was* Details of the biostratigraphical andpaleontological studies on the Toyoma Formation' will be treated in the next paper.

Masafumi MURATA and Yuji BANDO

24

I;+!+l Granites
L-M Trias.I;:.::.:l

I NAI Group

Up. Perm. §TOYOMA Form.

0"",==,5==~10=====,,1\5 km

Fig. 1. Distribution of the Toyoma Formation in
the southern part of the Kitakami Massif.

644.

Late Permian Araxoceras from Toyoma Formation

25

~I"··
walzakl
~y.~o

Q2J

C.
::J

~

C)

[EJ

o

Fig. 2.

2km

aL- FUKKOSHI Form.

«

OSAWA

Form.

z HIRAISO Form .

•TOYOMAx

Locality ofForm.

ID8B IWAIZAKI Limestone
Aroxoceros sp.

Geological map of the Toyoma Formation in the Motoyoshi Area.

eroded away throughout before the beginning of the Triassic. The upper
fossil zone is only confirmed in the U tatsu Area, where the Toyoma Formation
attains its maximum thickness.
The sea coast of Hiraiso, Motoyoshicho, Motoyoshi-gun, Miyagi Prefecture,
where the present Araxoceras sp. wasfound, is the type locality of the Early
Triassic (Scythian) Hiraiso Formation.
Here the black slate of the Toyoma Formation is covered by the Hiraiso Formation with distinct unconformity. The
Toyoma Formation is exposed sporadically along the sea coast from Hiraiso
to Iwaizaki, Kesennuma City, Miyagi
Prefecture, and rests conformably on the
Middle Permian Iwaizaki Limestone.
Although the Toyoma Formation is cut
by many faults, its thickness is estimatedabout 900 meters at Hirasio.
From the uppermost part of the Iwaizaki Limestone, Lepidolina 11lultiseptataL. kU11laensis fauna was described by
MORIKA w A (1960) and CHOI (1970, 1973).
The fauna of the Euphe11litopsis kitaka11liensis- Astartella toyo11lensis zone
could not yet be found from the lower
part of the Toyoma Formation in the
Hiraiso Area, except for a trace fossilof Notaculites toyo11lensis KOBA Y ASH!.
From a horizon 10 to 20 meters below
the base of the Lower Triassic Hiraiso
Formation at Hiraiso, however, theToyoma Formation yielded many molluscan fossils. Bellerophon sp., Leda sp.,
Yoldia sp., Anthraconeilo sp. and Nuculana sp. were listed from this horizon by
MABUTI and NODA (1934). Recently, thesenior writer distinguished Palaeoneilo

Masafumi MURATA and Yuji BANDO

26

South of KESENNUMA
IWAIZAKIHIRAI so Coast

z
o
I-

«

~

a:

o

LL

I...

«

Northeast of
UTATSUTOYOMAKITAZAWA

IAroxoceros SP.

~ ~g:~~:~~.

F

~

o
o

>x AS,Ps,B, E.

I-

SOOm

I
400
300
200
'00

~

D
D
~
~
--F

x

Slate
Sandy Slate
Sandstone
Conglomerate

~

~

!

!!l

.~

"
:ii'" ~ <::ii~ §" ~ ~" "."" '< ~ ~ :::<::'"" " .~'" ~q; '<'~" ~ i'S :.:::"~~ '§ '" ~....,~ -.i '" ~ ~" a:C>limestone
Fault
Fossil Locality"'(

Fig. 3. Columnar sections and faunal distributions of the Toyoma
Formation in the Toyoma, Motoyoshi and Utatsu areas.

ogachiensis HA YASAKA, Nuculopsis mabutii MURATA eMS), Paleyoldia? sp.,
Phestia kon'noi MURATA eMS), MourloniaeM.) toyomensis MURATA and Kitakamispira hanzawai MURAT A eMS) from thesame horizon by MABUTI and NODA (1934).
This molluscan fauna belongs to the
Palaeoneilo ogachiensis-Phestia kon'noieMS) zone of the middle part of the
Toyoma Formation.

The present specimen of Araxocerassp. (ct. A. kiangsiense CHAO) was collected by the senior writer at 15 meters
below the base of the Hiraiso Formationon the Hiraiso coast, along with many
specimens of Phestia kon'noi eMS).
On the Araxoceras Fauna
The genus Araxoceras was first es-

644.

Late Permian Araxoceras from Toyoma Formation

tablished by RUZHENCEV (1959) based
upon the Araxes fauna from the Dzhulfian of Armenian Dzhulfa. RUZHENCEV(1959) described some species of Araxoceras, i. e. A. latissimum RUZHENCEV(type species), A. trochoides (ABICH) andA. sp. nov., and subsequently he (1962,1963) described A. latum RUZHENCEV, A.
varicatum RUZH., A. glenisteri RUZH., A.
rotoides RUZH. and A. tectum RUZH. fromthe same Dzhulfian bed.
Another species, Araxoceras kiangsiense
CHAO, was repoted by CHAO (1965) fromthe Loping Coal Series of the Wuchiaping
Formation, lower part of the Loping
Series, in Kiangsi. According to CHAO
(1965), the Araxoceras fauna from theWuchiaping Formation in Kiangsi contains Andersonoceras, Prototoceras, Araxoceras, Vescotoceras and Pseudogastrioceras. This Kiangsi fauna is almost
comparable with the Dzhulfian fauna.
In Iran, the Dzhulfian fauna was reported by STEPANOV, GOLSHANI and
STOCKLIN (1969) and TEICHERT, KUMMELand SWEET (1973) from the PermoTriassic section at Kuh-e-Ali Bashi in
Iranian Julfa along the Araxes River,Northwest Iran, and it was identified
with the fauna repoted by RUZHENCEV(1959, 1962, 1963) and RUZHENCEV andSARYCEVA (1965). In the Zagros Range,
T ARAZ (1969, 1971) repoted the occurrenceof the Araxoceras fauna from the Dzhulfian bed of the Abadeh section, exposed
at Kuh-e-Hambast, near Abadeh.
In the western hemisphere, Eoaraxoceras ruzhencevi SPINOSA, FURNISH and
GLENISTER was described by SPINOSA.
FURNISH and GLENISTER (1970) from theuppermost Guadalupian (Amarassian) La
Colorada beds of the Valle de Las Delicias
in Coahuila, Mexico. They regarded
this species as a representative form of
the phyletic link between the Guadalupian
Paraceltitinae and the Dzhulfian Araxo-

27

ceratidae. The genus Eoaraxoceras may
be ancestral to the Ophiceratidae rather
than to the Araxoceratidae as alreadypointed out by BANDO (1973), judging fromthe characters of septa and whorls.
The genus Araxoceras may be also
ancestral to Otoceras s. str. which is wellknown from the Himalayas (Spiti, Niti
and Kashmir), Greenland, South China,
Siberia. North America and Timor?, but
Araxoceras has not been recorded to datein association with Otoceras s. str. Concerning the relation between the Dzhulfian Araxoceras and the Early Triassic
Otoceras various problems have beenpresented by many authors. Recently,
KUMMEL (1972) concluded that Araxoceras
is belonged to the Otoceratidae, andBANDO (1971, 1973) commented on theevolutional trends and morphologicalchanges from Araxoceras to Otoceras.
The Japanese Araxoceras from the
Toyoma Formation is similar to Araxoceras kiangsiense CHAO in the morphological characters, but the material is too
small to be identified with the Chinese
species. According to the observation On
the Iranian Aroxoceras, the ontogenetic
variation of shell form is considerably
prominent in each stage.

Description of Species
by Yuji BANDOSuperfamily Otocerataceae
HYATT, 1900
Family Araxoceratidae
RUZHENCEV, 1959
Genus Araxoceras RUZHENCEV, 1959
Type Species: Araxoceras latissimum RUZI-IENCEV, 1959, p. 58, figs. la, 2a.

Masafumi MURATA and Yuji BANDO

28

Remarks: The type species illustrated
by RUZHENCEV (1959, p. 59, fig. 1a) has
a wide umbilicus with ear-like projectedumbilical margin and widely tabulated
venter with sharply edged shoulders.
Araxoceras has no keel on the venter,but some species have a median ridgeon the venter.
The genus Araxoceras may be a form
intermediate from the groups of Vedioceras, Prototoceras and Avushoceras to
the group of Otoceras in the evolutional
trend judging from the morphologicaltransformations (BANDO, 1973).
Occurrence and geological horizon:Lower Dzhulfian bed at Dzhulfa in
Armenia and Iran, Loping coal series ofthe Wuchiaping Formation in Kiangsi,
South China, and middle part of the
Toyoma Formation, Northeast Japan.
Late Permian Dzhulfian stage.

Araxoceras sp. (d. A. kiangsiense CHAO)
Figs. 4-6
Compare:Araxoceras kiangsiense CHAO, 1965, p. 1820,
text-fig. 3a, pI. 2, figs. 10, 11.
Kiangsiceras rotule CHAO, 1965, p. 1820, textfig. 3c, pI. 2, figs. 4-6.

Description: - Shell rather involute,
whorls depressed, with broadly tabulated
venter and sharply projected umbilicalshoulders. Sides concave and ventral
shoulders sharply edged. Umbilical diameter about 1/3 of shell diameter, andumbilical wall steep, funnel-shaped.
Breadth of whorl widest at umbilicalmargin. Height of whorl about 1/2 ofwidth, and width of venter about 1/3 ofwidth of whorl. No ribs or striations onshell surface. Venter ornamented witha median ridge. Suture unknown.

Measurements (in mm.):D

H

W

U

HID

W!H

UID

16.6(13.1)

6.0

10.5

6.5(5.2)

0.36

1. 75

0.39

IGPS*, coIl. cat. no. 93346

Remarks :- The material at hand comprises only a single specimen, and halfof the whorl is an internal mould. The
specimen is small and represents ayounger stage of Araxoceras, but thepreservation of the shell is considerably
well for study. The specimen at handresembles that of Araxoceras kiangsiense
CHAO which was reported by CHAO (1965)
from th Loping Coal Series of theWuchiaping Formation in Kiangsi, South
China, but in detail it is difficult to* Abbreviation for the Institute of Geology
and Paleontology, Tohoku University, Sendai,
Japan.

identify the Japanese species with the
Chinese one, because the specimens fromJapan and China represent younger stageof Araxoceras.
The ill ustrated specimen of Kiangsiceras
rotule CHAO (1965, p. 1820, pI. 2, figs. 46) from the Loashan Shale of the Loping
Group in Kiangsi Province of South
China is similar to the present specimen
in the ventral features and whorl shape,
and the present writer thinks that the
species Kiangsiceras rotule may be thesame as Araxoceras kiangsiense judging
from the photographs by CHAO (1965).
The illustrated suture of Kiangsiceras
rotule by CHAO (1965, text-fig. 3c) is

644.

Late Permian Araxoceras !?'om Toyom,a Form,ation

4

5

Figs. 4- 6.

29

6

Araxoceras sp . (ct. Araxoce1'as I,iangsiense CH AO) .

4: Latera l v iew , 5: Ventral view, and 6: ' ''f hor! sectio n of t he ou te r whorl , IGPS,
colI. cat. no . 93346, x 2.
The specimen illustrated here was collected from t he black shale of the middle
part of the Toyoma Formation at Hiraiso, Motoyoshi -cho , Motoyoshi-gun, Miyagi
Prefecture, southern part of the Kitakami Mass if. Early Dzhulfian ? (Late Permian) .
ColI. M. MUR ATA, 1972.

similar to that of Araxoceras kia ngsiense
except for s light difference of first laterallobe. Moreover, the form of venter iscompletely similar to that of Araxoceras
1?ia ngsiense. The present writer considers
that J(iangsiceras rotule shou ld be ident ified as A. Iziangsiense judging from theirwhorl section, ventra l feature, ear-likeumbilical margin and suture.
The present specimen part ly resembles
that of Araxoceras varicatum RUZHENCEv(RuzHENcEv, 1962, p. 91, pI. 4, fig. 2) inthe form of the venter, but the former
has more convex and wider venter thanthe latter.
Occu1Tence and geological horizon:Black slate of the middle part of the
Toyama Formation at Hiraiso, Motoyoshicho, Motoyoshi -gun, Miyagi Prefecture,southern part of the Kitakami Massif,
Northeast Japan . Early Dzhulfian? of
the Late Permian. Reg. No. IGPS , colI.
cat. no. 93346, colI. M. MURATA, 1972.

References
BAN DO, Y. (1970): Lower Triassic A mmonoids from the Kitakami MassiE: Tran s.
Proc. Palaeont. Soc. Ja pan, N . 5 ., no . 79 ,p. 337- 354, pIs. 37-38.
- - (1971) : On the Otocera tidae , Triassic
ammonoids , and its strat ig raphical significance.
Kagawa Univ., Fac. Educ .,M em . Pt. 2 , no. 203, p. l - 11, pIs . 1- 3 ( inJapanese w ith English abstract ) .
- - (1 973): On the Otocera t idae and Ophiceratidae. Sci. Rep., Toholcu Uni v ., 2nd
S er. ( Ceol. ), Spec. Vol ., no. 6 (Hatai
Mem. Vol. ), p. 337- 351, pIs. 38, 39.
CH AO, K . (1965) : The Permian ammonoid bearing formations of South China.
S cienlia Sinica, vo l. 14, no. 2, p. 181 31825, pIs. 1, 2.
CHI SAKA, T. ( 1953) : On the Permian Systemof the sout h-westrn part of the Kitakami
Mountainland (Maiya District) . Siudies
Ceol. Mill . I nsl., T okyo Univ . Education,
no. 2, p. 1- 9 ( in Japanese).
CHOI , Dong Ryong (1970): On some Permian
fusulinids from Iwaizaki , N . E. Japan.
Jour. Fac . Sc i . Hokkaido Univ., S er . IV ,C eo l. & Mi neral., vo l. 14, no. 3, p. 313325 , pIs . 5- 8.
- - (1973) : Perm ian fusulinids from the
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16, no. 1, p. 1- 132, 12 text -figs., 3 tabs .,pIs. 1- 20.
HANZAWA, S. and M URATA, M. (1963 ) : The
paleontologic and stratigraphic considerations on the Neoschwagerininae and30

Masafumi MURATA and Yuji BANDOVerbeekininae, with the descriptions offusulinid Foraminifera from the Kitakami
Massif, Japan. Sci. Rep., Tohoku Univ.,
2nd Ser. (Ceol.) vol. 35, p. 1-31, 10 textfigs., 5 tabs., pIs. 1-20.
HAY ASAKA, I. (1924): Fossils in the roofing
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pI. 6.
- - (1967): Some Permian fossils fromSouthern Kitakami, VII. Two species ofPhmymatifer. Proc. japan Acad., vol. 43,
no. 2, p. 143-147.
INAI, Y. and TAKAHASHI, T. (1940): Geologyof the southern end of the Kitakami
Massif. Cont. Inst. Ceol. Pal., Tohoku
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Notaculites toyomensis, a new trail found in the Upper
Permian Toyoma Series in Nippon. japan.
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MABUTI, S. (1932, MS): Stratigraphy of the
Paleozoic rocks of the Tabashine-yama
Massif, southern part of the Kitakami
Massif. Tohoku Univ. Inst. Ceol. Pal.,
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- - and NODA, M. (1934): On the Paleozoic
rocks in the southern part of the Kitakami Massif. Ceol. Soc. japan, jour.,vol. 41, no. 489, p. 401-403 (in Japaeese).
MORIKA\YA, R. (1960): Fusulinids from the
Iwaizaki Limestone. Sci. Rep., Saitama
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- - (1967): Some Permian Conularidae fromthe Kitakami Massif, Northeast Japan.
Ibid., no. 36, p. 9-16, 2 text.figs., 1 pI.
- - (1969): Molluscan fauna of the Toyoma
Formation (Late Permian). Ibid., no.
38, p. 1-22, pIs. 1-4.
NAKAZAWA, K. and NEWELL, N. D. (1968):

Permian bivalves of Japan. Mem. Fac.
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Pal.
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- - (1962): Classification of the Family
Araxoceratidae. Ibid., no. 4, p. 88-103(in Russian).
- - (1963): New data on the Family Araxoceratidae. Ibid., no. 3, p. 56-64 (inRussian).
- - and SARYCHEVA, T. G. (165): Evolution
and change of marine organisms at theboundary between the Paleozoic andMesozoic. Trans. Paleont. Inst. Acad.
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B. F. (1970):
Araxoceratidae, Upper
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Ceo!., Bull., vol. 53, no. 3, p. 688-693.
(1971): Uppermost Permian and Permo-

644. Late Permian Araxooeras from Toyoma Formation
Triassic transition beds in Central Iran.
Ibid., vol. 55, no. 8, p. 1280-1294.
rEICHERT, C., KUMMEL, B. and SWEET, W.
(1973): Permian· Triassic strata, Kuh-e-

HiraisoIwaizaki
Karakuwa
Kiangsi31

Ali Bashi, Northwestern Iran. Bull.
Mus. Compo Zool., Harvard Univ., vol.
145, no. 8, p. 359-472, pIs. 1-14.

Kitazawa
ToyomaUtatsuTrans. Proc. Palaeont. Soc. Japan, N. S., No. 97, pp. 32-47, pI. 2-4, April, 30, 1975

645. ONTOGENIES OF TWO SPECIES OF SILICIFIED TRILOBITESFROM MIDDLE ORDOVICIAN, VIRGINIA *CHUNG-HUNG HU
Department of Earth Sciences, Cheng Kung University, Taiwan/~ -:;.=. 71+19='$* Iv F 1:::' ;<.*gjHt{t=~;g 2 :fiO)Mf*¥e1::
RemoPleurides caelatus:to J: V' Isotelus sp. O)Mf*lt. 7»,,::>'( WHlTTINGTON (1959) :to J: V' EVITT (1961) IC J: "?
'(8C.t(~nt,:iJ~, tJ:M~1}O)~I1fL~iJ~~ ~n '( ~ ,t,:o ~:1!Ht.l:~c.j~ifll{t~*~¥rU::.liIf1l: L,
EVITT Ie J: 7.> Isotelus sp. O)JJi(tmf*lt. R. caelatus r:::', it,: WHITTINGTON tc J: 7.>
Tretaspis sagenosus O)JJi(tmf*tJ: I? V'lc R. caphyrides 0)~fJ9f*lt. Isotelus sp. fc-tn.."fn~-t7.>,:,c~flf.Il?iJ'lcLt,:oiiJl ,'t!, ®:terial came from the Chambersburg
Limestone, Middle Ordovician, at Willow
Groove, 3 miles southwest of Woodstock,
Virginia. All of the materials are finegrained black limestone, containing very
abundant trilobite fragments, bryozoans,
ostracodes. a few brachiopods, andconodonts. The fragments are well silicified, and all were etched from thelimestone in the 5"", 10% diluted glacialacetic acid as employed by WHITTINGTON
and EVITT (1953).
About seventeen
species of trilobites with very well preserved growth sequence are recoveredfrom the original acidified residues.
The present report is a small part ofthese research, and the most undescribedmaterials will subsequently be publishedin near future.
The writer wishes to give his thanks
to Dr. K. E. CASTER, University of Cincinnati, Ohio, for his supervision andkindly reading over the present manuscript. Thanks are also given to Dr. F.
RASETTI, Universita Degli Studi, Roma,and the Geology Museum, University ofCincinnati, for permission to study theircollections. The figured specimens are

Introduction
The ontogenetic development of two
species of Middle Ordovician trilobites is
described.
They are Remopleurides
caelatus WHITTINGTON and Isotelus sp.
The first species can be segregated into
two groups by minor morphologic differences within the same species population. These bimodal traits are seen
either in the characters of the cranidium
or pygidium, or both, and are probably
represent the secondary sexual featuresof the two sexes of the respective
species. The sex of R. caelatus is determined by its sexual ratio or the numberof the individual specimens within thetwo morphologic groups (Hu, 1968, 1971).
The specimens of R. caelalus werecollected by Dr. F. RASETTI, Universita
Degli Studi, Roma, from the Edinburg
Formation, Middle Ordovician, 1.5 milesoutheast of Strasburg Junction, Virginia,
and those of Isotelus sp. are collectionsof the Geology Museum, University ofCincinnati, Ohio. The Isolelus sp. ma-* Received Sept. 30, 1974; read June 14,
1975.
32

645.

Mid-Ordovician Trilobites

all stored in the Geology Museum, University, Ohio (U. C. G. M.).

Systematic Paleontology
Family Remopleurididae
HA WLE & CORDA, 1847
Genus Remopleurides PORTLOCK. 1843
Remopleurides caelatus WHITTINGTON
PIs. 2, 3, and text·figs. 1, 2

Remopleurides caelatus WHITTINGTON, 1959,
pI. 4, figs. 1-25, text·fig. 5 only (not fig.
4), p. 40l.
Asaphidae (lsotelus sp.), EVITT, 1961, pI. 117,
figs. 1-19, pI. 118, figs. 1-34, 37-39, andtext-figs. 1-4 only, p. 986-995.

Discussion.- - The characteristics ofthis species conform to WHITTINGTON'S(1959) description represented by material
from the Lower Edingburg Formation,
located at 2-4, 6, and 7, Virginia. The
specimens are extremely abundant within
the faunal assemblage. Several hundredof both immature and mature skeletalfragments were acid-etched from a few
pieces of dark . limestone. Four species
are available under the genus Remopleurides, these are R. caelatus WHITINGTON, . R.· eximium WHITTINGTON, R.
asperulus WHITTINGTON, and R. caphyroides WHITTINGTON; the last two arevery rare, and also their growth sequences
are incompletely known.
The present species can be morphologically differentiated into two different
groups by their minor features. These
differences seem best to be attributed tosexual· dimorphism. In comparing two
cranidia and pygidia of the same size,the" male" glabella-is greatly expanded
laterally, the anterior glabella is nicked
or tongue-shaped, the posterior librigena
is narrow and minutely bifurcated, the33hypostoma is strongly impressed withthe concentric wrinkles and a mediumsized triangular median boss is present;
the "male" pygidium possesses a medianridge behind the bilobed terminal portion.
The cranidium of the "female" has anarrower glabella, longer anterior glabellar nock or tongue, the posterior
librigena is wider and has be bifurcation,
the hypostoma is smooth without amedian boss, and the pygidium possesses
no median ridge behind the bilobed
terminal portion.
The ontogenetic development of thepresent species shows a very complete
growth sequence from the early protaspis
to the fully developed adult form. The
early protaspis shows no special exoskeletal characteristics dorsally, no mediantubercle or paired anterior glabellar
granules; two pairs of short spines arelocated at both anterior and posterior
lateral margins. The meraspid skeletons
are well differentiated into cranidium,
librigena, hypostoma and pygidium. The
early immature pygidium possesses fiveaxial rings and elongate terminal portion.
In the later growth stage the five axial
rings are possibly developed into five
thoracic segments and an elongate terminal portion which correlates with a
specific thoracic segmental spine of thestill later growth stages. The holaspid
pygidium is developed laterally behindthe median spinous thoracic segment.
In the larger specimens the cephalicspines of the cranidium to be reduced
and the glabella increases in width laterally. The fixigena becomes narrow andthen disappear. The hypostoma increases
in length and its marginal spines are
reduced.
The present material suggests that the
supposed early protaspides of Isotelussp.
reported by EVITT (1961) possibly belong
to the early protaspides of Remopleiit-ides

34

Chung-Hung Hu

caelatus WHITTINGTON. The supposed
protaspides of Tretaspis sagenosus WHITTINGTON reported
by WHITTINGTON(1959) now appear to belong to Isotelus
sp. The earliest ontogenetic sequenceof R. caphyroides and R. caelatus were
unknown to WHITTINGTON, and themeraspides of Isotelus sp. were reported
by EVITT as "missing" in the record
possibly because of incomplete moltingof the youthful exoskeleton, or due todifferences in referred habitats at different stages in the life cycle. The
present assumption is based on the gradualappearance or absence of certain skeletal
ornamentation, e. g., the median tuberble
and paired granules on the glabella,number of marginal spines, and medianspinous thoracic segment. These morphologic metamorphoses are traceable
uninterruptedly from stage to stage.
For example, the cranidium possesses anmedian tubercle and no paired granules
on the anterior glabella, the pygidium
has a large elongate terminal portion
which correlates with the spinous thoracic
segment later, and the librigena or
librigeno-hypostoma shows a small tubercle internally and a depression externally(EVITT, 1961, pI. 118, figs. 13, 17), and theearly skeleton has two pairs of marginal
spines only. These features evidently
belong to the R. caelatus. On the other
hand, those larval glabellae which beara median tubercle and a pair of rather
minute anterior granules, and in which
the pygidium possesses no large elongate
terminal portion, and the early immatureskeleton has three pairs of marginal
spines, belong to Isotelus sp.
The early development of the present
species is compositely similar for themost part to that attributed by WHITTINGTON (1959) and EVITT (1961) toMenoparia genalunata Ross (Ross, 1951)
and Isotelus sp. All immature skeletonsare extremely convex, broadly rounded
and faintly marked with dorsal furrows
without any indication of segmentation;
the palpebral lobe is large, with two or
three pairs of spines extending along theshield margin. Thus, among these genera,
WHITTINGTON (1959) considered that
Menoparia and Remopleurides represent
two subfamilies of Remopleuridae, and
EVITT (1961) considered the Asaphidae
and Remopleuridae to be the families
whose phylogenies were closely related.
It is obviously that these interpretations
are derived from the different numbersof marginal shield spines, e. g., both ofthe early immature skeletons of Menoparia
and Remopleurides possess three pairsof marginal spines, whereas Isotelus sp.
possesses two pairs only. In fact, if thepresent assignment of the early protasp ides and mer asp ides of each genus asindicated in the preceding paragraph areacceptable, then the skeletal spines, either
two or three pairs, may not have verymuch phylogenetic or taxonomic significance, since, within the same genus,
certain species may have two or threepairs of marginal spines. For instance,
R. caelatus has two pairs, and R. caphyroides and R. eximius have three pairs.

Text-fig. 1. A growth sequence of Remopleurides cae latus WHITTINGTON. A, a problematic anaprotaspis, x 24; B, dorsal view of a metaprotaspis, x 24; C-E, G,dorsal and ventral
views of a few paraprotaspides, x 24, x 20, x 20; F, an early meraspid cranidium, x 18; H, I,
dorsal views of two late meraspid cranidia, x 20; ], a " male" hypostoma, x 20 ; K, a " female"hypostoma, x 20; L, M, ventral and dorsal views of a "male" cranidium, x 8; N, a "female"librigena, x 5; 0, a "male" librigena, x 5; P, a "female" cranidium, x 8. (All drawings
were made from photographs.)

645.

A

E

Mid-Ordovician Trilobites

c

B

G

F

J

K

N

35

o

H

L

o

p

36

Chung-Hung HuHere, the writer considers that the genera[sotelus, Remopleurides, and Menoparia
all possess no rostrum but the paired
librigena only, and are connected bymedian suture. These all belong to thegroup birostraloid as proposed previously
by the author (1971).
Figured specimens:"Male" form, Cranidia, U.C.G.M. 40416q,
w-z, aI, b', Librigenae, U.C.G.M. 40416z',aa, Hypostomara, U. C. G. M. 40416u, v,
Pygidia, U. C. G. M. 40416j'-1', p'.
" Female" form, Cranidia, U. C. G. M.
40416cc-ff, Librigenae, U.C.G.M. 40416y',bb, Hypostomara, U. C. G. M. 40416s', t',Pygidia, U. C. G. M. 40416q'.

Remopleurides caelatus WHITTINGTON,
ontogeny

The ontogenetic development of thepresent species is separated into threedivisions: protaspid, meraspid, andholaspid periods. The main developmental features of the protaspid period
may be briefly described as follows:
Protaspia period:-The shield is spherical to subspherical in outline, convex,
with the axis somewhat longer thanwide, and generally shows a medusoidform with the large shield above and the
spiny librigeno-hypostoma hanging below;
about 0.7-1.4 mm in length (sag.). The
surface is smmoth or faintly granulated,with a pair of pits and faint axial
furrows present on the anterior marginof the shield. The ventral aspect of theshield commonly has well-developed
librigena and hypostoma fused as asingle structure. The facial suture iswell developed in the earliest stage, but
is invisible from the dorsal view. The
palpebral lobe is. well recognized in thelater growth stage, which is indicatedby the course of the facial suture. It is

located at the anterior half of the shield.
The protopygidium is possibly developed
immediately behind the posterior end of
the facial suture and has four or five
faint segments. The late protopygidium
is round and consists of five uniform
annular, a large terminal portion, and fivepleural bands. The internal surface ofthe protopygidium has four pairs ofmarginal spines along the narrow posterior doublure. The present period is
subdivided into the anaprotaspid, metaprotaspid, and paraprotaspid stages by
the presence or absence of the axial lobe,
facial suture, and protopygidium.
Anaprotaspid stage (PI. 2, fig. 1, andtext-fig. lA):-The shield is about 0.7 mm
in length (sag.), spherical to oval, somewhat longer than transverse, convex,
domed, without any distinct marking on
the dorsal surface, except for finegranules.
Only a single specimen has been recovered; the ventral view of the specimen shows a rounded cavity; no librigena
or hypostoma are in place. The shield
margin is incomplete and irregularly
wedge-shaped, which may be the resultof breakage.
Metaprotaspid stage (PI. 2, fig. 2, andtext-fig. 18):-The shield is round to
sub round in outline, dome-shaped, somewhat longitudinally convex, and about
0.7-1.0 mm in length (sag.). Possibly apair of spines at the anterior lateral
margin projects obliquely downward fromthe frontal border; another pair projects
postero-laterally immediately from behindof the posterior border. The dorsal
surface of the shield is marked by a pairof distinct anterior pits. The axial andthe pleural lobes are incompletely differentiated. The surface of the shield iscovered by faint granules and a longitudinal furrow occurs along the medianaxis. The under view of the specimen

645.

Mid-Ordovician Trilobitesshows a round hollow with the narrow,crescentic, evanescent librigena locatedat the right side of the shield margin.
This stage is equivalent to the earliest
protaspis of EVITT (1961).
Paraprotaspid stage (PI. 2, figs. 3-7, 12,
13; pI. 3, figs. 1-4, 21, 22; and text-fig.
IE, G, and 2A, B.):- The shield lengths
vary from 1.0-1.2 mm (sag.) ; subsphericalin outline, with the anterior half slightly
broader than the posterior end: convex
along the axial lobe, but moderately
flattened at the anterior and strongly
convex behind.
A pair of elongate
anterior pits is distinctly impressed along
the incompletely developed axial furrow.
No glabellar furrows or segments arevisible. The facial suture appears behind
the antero-lateral cephalic spines and in
front of the mid-length of the shield; it
curves strongly laterally along therounded palpebral lobe. The posteriorfacial suture rounds downward, under
and inward almost to the posterior midline, then makes a short-cut at an acuteangle to the free margin. The posterior
cephalic margin is not known, but ispossibly immediately behind the equatorial line, between the posterior end of the
facial suture lines. In some early shield
the protopygidium is indicated by a few
faint segments.
Librigena and hypostoma are fused intoa single structure. The librigena is anarrow crescentic band, and its lateralside has a facial suture extending upward
along the vertical ocular platform. The
hypostoma is subcircular in outline,
convex, and its central body is V -shaped;
its anterior is connected with the librigena,
and tapers back to form a sharp projection. The lateral margin is crescentic
and is projected oblique-laterally into four
pairs of long slender spines. The lateralhypostomal borders are nearly vertical,
thickened slightly at the free margin,37

and without distinct doublure.
The
anterior end of the librigena is sometimes
flat or slightly depressed externally, andpossibly bears a small tubercle internally(EVITT, 1961, pI. 118, figs. 10, 13, 17).
The associated late paraprotaspid
pygidium is not articulated with thecranidium. It is convex, round to subround in outline, about 0.5-0.7 mm inlength (sag.) with well defined axial andpleural lobes. The axis is convex, elevated above the pleural lobes, gently
tapering at the posterior, and divided
into five nearly uniform axial rings andan elongate terminal portion. The pleurallobe is twice as wide as the axis, slopes _gently to the lateral margin except postero-laterally at the axal region, which isbent down nearly vertically. The ventral
side of the specimen shows four pairs oftiny spines situated along the posterior
pygidial margin. The doublure is widest
at the posterior, diminished anteriorly,
and disappears at the anterior lateralcorners.
The present stage is correlated withthe latest protaspides of EVITT (1961, p.
988), and with the meraspid degree 0 of
WHITTINGTON (1959, p. 406).
M eraspid period: - The cranidium of
pygidium are generally disarticulated.
Therefore, any association of these parts
is synthetic. In the present species the
cranidium is an isolated part, not associated with the librigena and thepygidium. It is small and subquadrate
in outline, convex, and retains a pair oflong anterior cephalic spines. It has no
distinct glabellar furrow. The palpebral
lobes are large and located between the
cephalic spines and the narrow posterior
fixigena. The large specimen lacks theanterior cephalic spines, but has welldeveloped dorsal furrows and sickleshaped palpebral lobes. The largest
cranidium shows that the fixigena is38

Chung-Hung Hu

reduced by lateral expansion of theglabella between the eye lobes; it iscrescentic, narrow and disappears during
the later growth stage.
The librigeno-hypostoma is differentiated into isolated parts, i. e., librigena
and hypostoma. The librigena is narrow,crescentic, bears a short genal spine.
The hypostoma is elongate, and the four
pairs of marginal spines and a posterior
spine are still retained.
The early meraspid pygidium is triangular, convex, and consists of threepairs of marginal spines and a long
median axial one which is curved anddirected upward at the posterior. The
late meraspid pygidium is quadrate tosubquadrate in outline, convex and has
two to three pairs of short broad pleuralspines. The broad axial lobe is divided
into two rings and a broad semicircularterminal portion. The axial ring is without spine.
Although the median spinous thoracic
segment of the present stage is possibly
correlated with the terminal portionthe sixth axial ring-of the protopygidium, and the latest meraspid pygidium,or true pygidium, which is added to thespinous segment, is newly developed;
this pygidium does not possess an axial
spine, convexity, or an elongate terminal
portion. If the present interpretation is
acceptable, then it is possibly that thepresent species has five thoracic segments
in front of the median axial spine, since
only in the earliest stage its recognizable,or paraprotaspid pygidium has five axial
rings in front of the elongate terminal
portion.
Early meraspid stage (PI. 2 figs. 8-11;
pI. 3, figs. 5-7; text-figs. IF, and 2C, D):The cranidium is about 1.0-1.4 mm inlength (sag.), trapezoidal in outline,
moderately convex, and possesses a pairof cephalic spines. The glabella is ex-

panded from the occipital furrow forwardly to the anterior margin and noglabellar furrow is visible. The anterior
margin arches gently forward; no preglabellar field is present. The occipitalring is moderately convex, bearing a
minute node close to the anterior margin.
The occipital furrow is narrow and dis~inctly impressed with an anterior edgethe glabellar base-which is higher thanthe occipital ring. The fixigena iscrescentic, faintly delimited by dorsal
and palpebral furrows, and its greatest
width is situated on the mid-line of theglabella (tr.). The posterior fixigena israther narrow (sag.), low, and sharply
pointed laterally from the side of theoccipital ring.
The hypostoma is elongate, convex,
having a wedge-shaped median body.
The median body is faintly delimited bylateral furrows and continuously runs
into a median spine directed toward theposterior end. The four pairs of lateral
marginal spines are shorter and stouter
than in the early growth stage; they are
equi-spaced and radiated from the margin.
The pygidium is about 0.5-1.0 mm
length, convex, triangular in outline,
bearing a long stout upwardly curving
median axial spine. The axial lobe israther broad, divided into 2-3 segments
by indistinct axial furrows, and convex
above the pleural lobes. Three pairs ofthorn-like pleural spines, in essence extensions of the pleural bands are directed
postero-laterally. The ventral view ofthe specimen shows a narrow curved
doublure along the margin with a medianposterior notch. The median segmental
spine is possibly located at the third
axial ring-two complete axial rings anda half ring-, and behind this spinous
segment it may be assumed that there isone more rudimentary segment.
The present stage differs from the645. Mid-Ordovician Trilobites
paraprotaspis in having a well definedglabella and palpebral lobes; the pygidium is without ventral marginal spines,
and the librigeno-hypostoma is well differentiated into isolated parts - thelibrigena and the hypostoma.
Late meraspid stage (PI. 2, figs. 14-17;
pI. 3, figs. 7-11, 23-24; text-figs. lH, I,
and 2F.);-The cranidium is about 1-42.0 mm in length (sag.), and moderately
convex; the glabella has expanded between the pleural lobes so that the
fixigena is gradually eliminated, and thedorsal furrow coincides with the palpebral
furrow. This furrow is broadest at its
mid-point between the palpebral lobes(tr.), and narrows at both anterior andposterior ends. The anterior margin of
the glabella is broader than the occipitalring (tr.). The occipital ring is lenticular,
convex, well marked by an occipital
furrow, and bears a small node near theanterior edge of the occipital ring andis decorated by a serration of marginal
spines. No anterior fixigena is observed
except for a pair of narrow ridges continuously running from the anterior
palpebral lobe to the anterior lateralcorners of the glabella. The palpebral
lobe is large and broad, sickle-shaped,
and encircles the narrow fixigena fromthe side of the occipital furrow to theposterior lateral corners of the glabella.
The posterior lateral fixigenae are rather
narrow, and show only a pair of broadbased spines extended laterally from theboth sides of the occipital ring.
The librigena (pI. 3, figs. 23, 24) is essentially like that of an adult form, witha narrow ocular platform outside of thevery large eye lobes. The rear librigenal
border is narrow and strongly divaricatedat the posterior from the lateral border.
Neither lateral nor posterior furrows arerecognizable. The genal spine runs continuously from the lateral border; it is39

medium-sized and sharply pointed at theposterior. The doudlure is broad, runningparallel to the lateral border except at
its anterior end, near the median suture,
where it is narrow, arched, and marked
with a small pit underneath and withtubercles internally.
The pygidium is generally hexagonalin outline, convex, and the axial rings
are faintly impressed. The first ring isdistinctly separated into a half and amain ring by a furrow; the second andthird rings may be outlined by shallow
ring furrows; the anterior furrow being
the deepest, and the following being progressively shallower and the rings
shorter. The pleural lobes are rather
narrow, bearing three to four pairs ofspines which extend backward from theaxial ring. The first pair of spines isthe longest, its facet angle is thick andshoulder-trap like. In the under view ofthe pygidium it has a broad doublure
which is under-curled with a posterior
median notch.
The pygidium of the present stage ispresumably developed behind the medianspinous segment, since there is no any
more spinous segment is observed.
Behind this spinous segment three morethoracic segments and a true pygidium
will be added laterally, and the holaspid
form is achieved.
Figured specimens;-Anaprotaspis,
U.C.G.M. 40416,(Metaprotaspis, U.C.G.M.
40416a, Paraprotaspides, U. C. G. M. 40416bf, k, I, cl , d l , fl, gl, Early meraspides,
U.C.G.M. 40416g-j, h, iI, Late meraspides,
U. C. G. M. 40416m-p, Y-l/, Protaspid hy·
postoma, U. C. G. M. 40416r-t.
Family Asaphidae BURMEISTER, 1843
Genus Isotelus DEKAY, 1842
Isotelus sp.

Chung-Hung 'Hu

40

A

B

E

F

o

G

J

H

K

Text-fig. 2. A growth sequence of Remopleurides caelatus WHITTINGTON . . A, B, dor~al
and ventral views of a protopygidium, x 25; C, D, ventral, lateral; and dorsal views of twoearly meraspid pygidia, x 20; E, F, dorsal view of two late meraspid pygidia, x 20; G, ventral
view of a pygidium,. x 15; H, dorsal view of a pygidium associated with a few of thoracic
segments, x 6; L-K, ventral views of threep rotaspides, showing the librigeno-hypostoma.
(Arrows indicate the correlated parts of the skeleton; half arrowdndicates thoracic segment,
solid arrow indicates the spinous segment, dotted arrow indicated pygidium. L-K, redrawn
from EVITT, 1961, with slight modification.) (All drawings were made frqrn photograpps.).

645.

Mid-Ordovician Trilobites

Pl. 4, figs. 1-33, and text-fig. 3
Isotelus Sp., EVITT, 1961, pi. 117, figs. 20-23,
pi. 118, figs. 35, 36, only (not pi. 117,
figs. 1-19, and 118, figs. 1-34, 37-39), p.
985-995.
Remopleurides, EVITT, 1961, text-figs. 5, 6, p.
785-995.
Tretaspis sagenosus WHITTI)lGTON, 1959, pi.
26, figs. 1-13 only, p. 55.
Remopleurides caelatus WHITTI)lGTON, 1959,
pi. 3, figs. 1-6, text-fig. 4, p. 40l.
R. caphyroides WHITTINGTON, 1959, pi. 10,
figs. 8-13, 15, 16, 18, 20; pi. 11, figs. 1-4,
p. 391-412.
R. caphyroides? WHITTI)lGTON, 1959, pI. 11,
figs. 9-11, p. 414-420.

Discussion:- The present species isrepresented by more than a hundred
immature and mature specimens. Following EVITT (1961), they are recognized as
Isotelus sp., without any attempt asevaluation of the species. The early
immature forms were placed in Tretaspis
sagenosus WHITTINGTON and Remopleurides caphyroides WHITTINGTON by
WHITTINGTON (1959), and in Remopleurides by EVITT (1961). The material,
which I have studied, suggested that theearly immature forms associated which
Isotelus sp. by EVITT (1961) may belong
to Remopleurides caelatus and the meraspides of Remopleurides caphyroides
WHITTINGTON (1959) belong to Isotelus
sp. The reason for the present assignment is based on the unbroken grown
sequence; the morphologic developmentfrom the early larval stage to the adultform is continuous. For example,. theskeletal spines situated on the cranidial
and pygidial margins are continuously
present throughout of the meraspid·
period. The meraspid pygidium do notpossess an elongate terminal portion as
does Remopleurides. The medianglabellar tubercle remains throughout of
the growth of the animal. The paired

41

anterior glabellar granules are reduced
only during the late meraspid stage.
Furthermore, the present material fromthe Chambersburg Limestone contains
very abundant mature and immature
specimens, whereas the forms from the
Edinburg Formation are only a few largesized fragments and no complete grownseries can be traced.
Figured specimens :-Cranidia, U .C. G.l\t1.
40417a, b, Librigenae, U. C. G. M. 40417v.
w, Hypostomata, U. C. G. M. 40417r-u,
Pygidia, U. C. G. M. 404l7z, b', c'.
Isotelus sp., ontogeny

The ontogenetic development of thepresent species is represented by four
growth stages only; metaprotaspid, paraprotaspid, early meraspid, and latemeraspid stages. The early protaspid or
anaprotaspid skeleton in unknown. It
seems that the protaspides may show
similar features throughout the protaspid
period, but morphologic changes, such as
the cephaliZation, pygidial segmentation
etc., are possibly progressively differentiated underneath the exoskeleton, and in
this respect are quite unlike the ptychopariids : Parabol inoides contractus FREDERICKSON, Aphelaspis subditus PALMER, andJVelleraspis lochmanae Hu (Hu, 1969),
etc. where parts of segments are added
one by one to the cranidium and are
distinctly seen on the dorsal surface.
The delay of the exoskeletal segmentation
between the cephalon and the pygidium
may indicate that the animal had increased the period of pelagic larval life.
Metaprotaspid stage (PI. 4 figs. 1-3 andtext-fig. 3A, B.):-The shield is oval,
convex, about 0.6-0.75 mm in length(sag.), . having well defined axial andpleural lobes. The axial lobe extends
the full length of the shield, expanding
slightly forward and marked with a42Chung-Hung Hu

median tubercle at one-third of the length(tr.). The fixigena is well defined by adorsal furrow, gently convex, uniformly
and abruptly sloping along the anterior
margin, and about the same width as the
mid-line of the glabella (tr.). Three pairsof slim spines arise from the margin,

one anterior lateral, one at the greatest
width, directed outward and backward,
and a posterior pair situated close
together and backwardly directed. In
the under view of the skeleton there isa narrow doublure extending around theposterior half of the shield, and reaching

Text-fig. 3. A growth series of Isoteus sp. A, B, dorsal and ventral views of a possible
metaprotaspid shield, x 23; C-F, side, frontal, oblique, and dorsal views of a few paraprotaspides, x20; G, dorsal view of an early meraspid cranidium, x17; H, dorsal view of a latemeraspid cranidium, x 10; I, J, ventral and dorsal views of a protopygidium showing theassociation of the occipital segment, x 24; K, L, dorsal and ventral views of a protopygidium,x 24; M, a meraspid hypostoma, x 10; N, hypos tom a, x 7; 0, a possible early meraspid pygidium, x 20; P, a librigena, x 5; Q, dorsal view of a pygidium, x 4; R, dorsal view of ~possible late meraspid pygidium, x 9; S, dorsal view of cranidium, x 5. (Arrows indicate thecorrelated parts of the animal skeleton; solid arrow indicates median tubercle; dotted one
indicates fixigenal spine; half arrow indicates paired glabellar granules.). (AU drawings
were made from photographs.)

Explanation of Plate 2
Figs. 1-30. Remopleurides caelatus WHITTI:-.1GTO=-:.
1. A possible anaprotaspid shield, showing no anterior pits, axial differentiation, andand pleural lobes. x 24, U. C. G. M. 40416.
2. A possible metaprotaspid shield, showing the appearence of the anterior pits. x 24,
U. C. G. M. 40416a.
3-7, 12, 13. Six paraprotaspid shields, showing the naterior and posterior marginal
spines, and the differentiation of the axis and the pleural lobes. 3, x 24, U. C. G. M.
40416b; 4, x 20, U. C. G. M. 40416c; 5, x 24, U. C. G. M. 40416d; 6, x 24, U. C. G. M.
40416e; &, x 20, U. C. G. M. 40416f; 12, x 18, U. C. G. M. 40416k; 13, x 20, U. C. G. M.
404161.
8, 9, 10, 11. Four early meraspid cranidia, showing the anterior spines and the indistinct axial furrows. 8, x 18, U. C. G. M. 40H6g; 9, x 18, U. C. G. M. 40416h; 10, x 20,
U. C. G. M. 40416i; 11, x 20, U. C. G. M. 40416j.
14, 15. Dorsal views of two late meraspid cranidia, showing the distinct glabellar
furrows. 14, x 20, U. C. G. M. 40416m; 15, x 18, U. C. G. M. 40416n.
16, 17. Two late meraspid cranidia, showing the lateral furrows. 16, x 16, U. C. G. M.
404160; 17, x20, U.C.G.M. 40416p.
19. A meraspid hypostoma, showing the increasing of the median body and the reduction of the marginal spines.
20-22. Three protaspid hypostomata; notice the marginal spines, and the differentiationof the rostrum, and the librigenae. 20, x 20, U. C. G. M. 40416r; 21, x 20, U. C. G. M.
40416s; 22, x 21, U. C. G. M. 40416t.
23, 24. Two possible male forms of hypostomata; notice the anterior median nodes.
23, x 20, U. C. G. M. 40416u; 24, x 20, U. C. G. M. 40416v.
18, 25-30. Six well preserved male cranidia. 18, x 14, U. C. G. M. 40416q; 25, x 10,
U. C. G. M. 40416w; 26, x 11, U. C. G. M. 40416x; 27, x 7, U. C. G. M. 40416y; 28, x 8,
U. C. G. M. 40416z; 29, x 9, U. C. G. M. 40416a'; 30, x 8, U. C. G. M. 40416b'.

Hu:

Middle O?"do vician trilobit es

Plate 2

645. Mid-Ordovician Trilobites

43

A

B

c

o

E

F

G

H

J

K

L

il
M

o

N

Q

R

5

44

Chung-Hung Hu

forward to a point beneath the base of
the lateral spines. The external surface
is covered by very faint granules, andthere is a very faint transverse depressedline at the posterior one-thirds of thelength of the glabella and the fixigenae(tr.); this suggests a possible segmentalline lying between the cephalon and thepygidial shield.
Paraprotaspid stage (PI. 4, figs. 4-6, 11,
16-19 and text-fig. 3C- F, 1- L.) : -Theskeleton is strongly convex, about 0.8-1.2
mm in length (sag.), and in certain small
specimens the anterior and the posterior
margins may curve to oppose each other.
The cranidium is quadrate to subquadrate in outline, convex, with well differentiated dorsal furrows, and no glabellar furrows.
The anterior lateral
margin has a pair of long slim cephalicspines extending anterior laterally fromthe cranidial corners. The palpebral lobe
is large, located between the cephalicspine and the narrow posterior fixigena.

No distinct palpebral furrow or fixigenal
separation is present. The anterior
glabella is marked by a pair of minute
anterior tubercles and a medium sized
median node. Some small specimens
have a pair of spines directed posterolaterally from the extreme lateral end of
the posterior fixigena.
The pygidium is trapezoidal in outline,
convex, with the narrow axial lobe above
the pleural region. The axial lobe isnarrower than the pleural region, divided
into six uniform axial rings by several
indistinct furrows. The pleural region isdivided into six pleural bands, which areof the same width and uniformly curved
at the posterior. The ventral side of thepygidium is decorated by four pairs ofminute spines along the narrow, rear
doublure, and a pair of long lateral spines
is situated at the posterior lateral pygidial
margin.
The present stage differs from theprevious in having the pygidium differ-

Explanation of Plate 3
Figs. 1-32. Remopleurides caelatus WHITTli\"GTON.
1-4. Four paraprotaspid pygidia. 1, x 25, U. C. G. M. 40416c' ; 2, x 25, U. C. G. M. 40416d' ;3, 4, x 25, U. C. G. M. 40416f', g'.
5, 6. Oblique and dorsal views of two early meraspid pygidia, showing the medianaxial spine. 5, x20, U.C.G.M. 40416h'; 6, x20, U.C.G.M. 40416i'.
7-10. Four late meraspid pygidia. 7, x 25, U. C. G. M. 40416j'; 8, x 20, U. C. G. M. 40416k' ;9, specimen missing; 10, x 20, U. C. G. M. 404161'.
11-14. Dorsal and ventral views of four pygidia. 11, specimen missing; 12, x 15,
U. C. G. M. 40416m'; 13, x 18, U. C. G. M. 40416n'; 14, x 15, U. C. G. M. 404160'.
15, 16. Dorsal and ventral views of a male and female forms of pygidia; notice thepresence (male) and abesence (female) of the posterior median ridge. 15, x 15,
U. C. G. M. 40416p'; 16, x 15, U. C. G. M. 40416q'.
17, 18. Dorsal and oblique views of a pygidium, associated with one to four thoracic
segments. x 6, U. C. G. M. 40416r'.
19, 20. Two hypostomata, possibly belong to female form, showing no antherior mediannode. 19, x 20, U. C. G. M. 40416s'; 20, x 20, U. C. G. M. 40416t'.
21,22. Two isolated protaspid librigenae. 21, x 16, U. C. G. M. 40416u' ; 22, x 16, U. C. G. M.
40416v'.
23, 24. Two meraspid librigenae. 23, x 12, U. C. G. M. 40416w' ; 24, 20, U. C. G. M. 40416x'.
26, 27. Two male librigenae. 26, x 8, U. C. G. M. 40416z'; 27, x 5, U. C. G. M. 40416aa.
28. A female librigena. x 5, U. C. G. M. 40416bb.
29-32. Oblique, dorsal, and ventral views of four complete cranidia; notice the longer
glabellar neck and the smaller ocular lobe compared with that of male form.
x 10,
x 9, x 8, x 8, U. C. G. M. 40416cc-ff.

x

Hu :

Middle Ordovician trilobites

Plat e 3645. Mid-Ordovician Trilobites

45

entiated from the cranidium, the facial
Late meraspid stage (PI. 4, figs. 12, 13,
suture has migrated upward onto the23, 24, 28 and text-fig. 3R, M, R.) :-The
dorsal surface, and the posterior paired
cranidium is subquadrate in outline,
pygidial spines are more widely separated.
longer than wide, moderately convex,
Early meraspid stage (PI. 4, figs. 7-27,
about 1.3-2.0 mm in length (sag.). The
27, and text-fig. 3G, 0.):- The cranidium
glabella is expanded forwardly from theis subspherical in outline, convex, 0.9-1.2
narrow occipital ring (tr.) ; a pair of weU
mm in length (sag.). The glabella isdefined glabellar furrows exist behind thefaintly delimited by dorsal furrows,
mid-line of the glabeUa, directed postericylindrical, slightly expanded forwardly
orly from the shaUow dorsal furrow tofrom the occipital ring, and without
the occipital furrow. No preglabellar
glabellar furrows. The anterior glabella
field is present. The anterior border isbears a pair of granules and a mediannarrow, gently convex, with median point
tubercle. The occipital ring is wellat the anterior end. The crescentic
delimited by a narrow, distinct occipital
occipital ring is convex, and weU delimited
furrow which is crescentic, strongly
by a narrow distinct occipital furrow.
curving backward, and having a minute
The medium sized palpebral lobe is 10median node. No preglabellar field orcated behind the mid-length of the glabanterior border is seen except for a pairella (tr.); it is gently convex, without adistinct palpebral furrow. The fixigenaof long, slim cephalic spines extending
antero-Iaterally from the lateral corners
is rather narrow, moderately convex,of the anterior cranidium. The fixigena
directed upward from the dorsal furrow.
curves laterally, crescentic, with a well
The narrow posterior fixigene is triangudelimited free margin, convex, gently
lar-transverse, narrower than the occipital
sloping downward from the dorsal
ring (tr.), and the border furrow is wellfurrow. The palpebral lobe is rather
defined. The surface is covered by faintnarrow and faintly separated by the
granules; a pair of superciloid granules
palpebral furrow. The anterior branchoccur along the anterior furrow.
A
median tubercle is located near theof the facial suture is short and divergently convex, and the posterior one runs
occipital furrow, and a pair of minutemostly parallel to the posterior lateral
granule seems to be present of theborder.
anterior glabella near the edge of the
The pygidium is moderately convex,
frontal furrow.
oval-transverse, without any distinct
The pygidium is ovate-elongate in outsegmental furrow. The axial lobe tapers
line, convex, with the posterior margin
at the posterior end, convex, above thenotched. The convex axial lobe is rather
pleural lobe. The pleural lobe is faintly
narrower than the pleural lobe, tapering
separated by dorsal furrow, wider thanslightly at the posterior end, and marked
the axis (tr.), and decorated by threeby several axial rings. The pleural lobe
pairs of short marginal spines along theis convex above the flat broad marginal
posterior margin. The broad margiIIal
border!.. and"divlde-d . into four ot fiveborder is convex, shallowly delimited._by~' . pleurill, bands' by'well defined furrows.
and inner marginal furrow. The anty;t;ior . " Fig~r.ed specimens: - Metaprotaspides,
end of the axis is associated with :an
p.C.G.~M. '40~l7,. 40417a, b, Paraprotaincomplete thoracic segment. The skele-. spides, V,C .. C.. M., 40417d, c, i, Early
tal surface is faintly granulated.
meraspides,. U. C. G. M. 40417e-h, n-q,

Chung-Hung Hu

46

Late meraspides, U.C.G.M. 40417j, k, x, y.

References
BEECHER, C. E. (1893): The larval stages oftrilobites. Am. Geol. vol. 16, p. 166-197,
pI. 8-10.
COOPER, B. N. (1953): Trilobites from theLower Chamblainian Formation of theAppalachian Valley. Geol. Soc. America,
Mem. 55, 66 p., pIs. 1-19, 2 text-figs, 1
table.
EVITT, W. R. (1961): Early ontogeny in thetrilobites family Asaphidae. Jour. Paleont., vol. 35, no. 5, p. 986-995, pIs. 117118, 6 text-figs.
Hu, C. H. (1968): Notes on the ontogeny
and sexual dimorphism of Upper Cambriantrilobites of the Welleraspis faunule from
Pennsylvania. Jour. Nanyang Univ., vol.
2, p. 321-357, pIs. 1-4, 8 text-figs.
- - (1971): Ontogenies and sexual dimorphism of Lower Paleozoic Trilobita.
Palaeontographica Americana, vol. VII,no. 44, p. 31-135, pIs. 8-26, 58 text-figs.
Ross, R. J. (1951): Ontogeny of three Garden
Cith (Early Ordovician) trilobites. Jour.

Explanation of Plate 4
Figs. 1-33. Isotetus sp.
1-3. Three metasprotaspid shields, notice the three pairs of marginal spines and the
median tubercles. 1, x 23, U. C. G. M. 40417; 2, x 23, U. C. G. M. 40417a; 3, x 23,
U. C. G. M. 40417b.
4-6. Side, ventral, and obliquely views of two paraprotaspid shields. 4, 5, x 20,
U.C.G.M. 40417d; 6, x20, U.C.G.M. 40417c.
11. Dorsal view of a paraprotaspid shield; notice the paired fixigenal spines. 11, x 20,
U. C. G. M. 40417i.
7-10. Four early meraspid cranidia, showing a pair of anterior glabellar nodes and theabsence of fixigenal spine. 7, x17, U.C.G.M. 40417e; 8, x20, U.C.G.M. 40417f; 9,x17, U.C.G.M. 40417g; 10, x17, U.C.G.M. 40417h.
12, 13. Dorsal views of two late meraspid cranidia; notice the deepening of the dorsal
furrow and the position of the median tubercle. 12, x 10, U. C. G. M. 40417j; 13, x 10,. U. C. G. M. 40417k.
14, 15, 31. Dorsal views of three cranidia. 14, x 10, U. C. G. M. 404171; 15, x 7, U. C. G. M.
40417m; 31, x 5, U. C. G. M. 40417a'.
16, 17. Dorsal and ventral views of two early meraspid pygidia. x 24, U. C. G. M.
404170, n.
18, 19. Dorsal and ventral views of an early meraspid pygidium, showing the occipitalsegment and a pair of fixigenal spines in place. x 24, U. C. G. M. 40417q, p.
20-23. Dorsal and ventral views of four different sized hypostomata; notice the lateralexpanding of the marginal border. 20, x 10, U. C. G. M. 40417r; 21, x 7, U. C. G. M.
40417s; 22, x 9, U. C. G. M. 40417t; 23, x 5, U. C. G. M. 40417u.
24-26. Three different sized librigenae; notice the wideni. g of the ocular platform andthe broad doublure. 24, specimen missing; 25, x 5, U. C. G. M. 40417v ; 26, x 5, U. C. G. M.
40417w.
27. An earliest late meraspid pygidium articulating in series with a thoracic segment,
and showing three or four pairs of posterior marginal spines. x 20, U. C. G. M. 40417x.
28. Dorsal view of a late meraspid pygidium, showing the deep dorsal furrows, andposterior marginal notch. x 9, U. C. G. M. 40417y.
29, 30, 32, 33. Dorsal and ventral views of four complete pygidia; notice the disappearence of the dorsal furrows and the broad doublures. 29, x 6, U. C. G. M. 40417z;
30,32, x4, U.C.G.M. 40417b'; 33, x6, U.C.G.M. 40417c'.

Hu:Middle Ordovician trilobites

Plate 4

645. Mid-Ordovician Trilobites
Paleont., vol. 25, p. 578-586, pIs. 81-84.
R. et al. ed. (1951): Treatise on
Invertebrate Paleontology, Part O,Arthropoda, 541 p., 415 text-figs. Geol. Soc.
America & Univ. Kansas.
WHITTINGTON, H. B. (1956): Silicified Middle
Ordovician trilobites (the Odontopleuridae). Mus. Compo Zool., Bull., vol. 114,
no. 5, p. 159-289, pIs. 1-24, 25 text-figs.

MOORE,-

47(1959) : Silicified Middle Ordovician
trilobites (Remopleuridae, Trinucleidae,
Raplisphuridae). Mus . .comp. Zool., Bull.,vol. 121, no. 8, p. 373-496, pIs. 1-36, 8
text-figs.
& EVITT, W. R. (1953): Silicified Middle
Ordovician trilobites. Geol. Soc. America,
Mem., 59, 135 p. pIs. 1-33, 27 text-figs.,
2 tables.

50

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O

645.

Mid-Ordovician Trilobites

Paleont., vol. 25, p. 578-586, pIs. 81-84.
R. et al. ed. (1951): Treatise on
Invertebrate Paleontology, Part O,Arthropoda, 541 p., 415 text-figs. Ceo!. Soc.
America & Univ. Kansas.
WHITTINGTON, H. B. (1956): Silicified Middle
Ordovician trilobites (the Odontopleuridae). Mus. Camp. Zool., Bull., vol. 114,
no. 5, p. 159-289, pIs. 1-24, 25 text-figs.

MOORE,

47(1959) : Silicified Middle Ordovician
trilobites (Remopleuridae, TrinucJeidae,
Raplisphuridae). Mus. Camp. Zool., Bull.,vol. 121, no. 8, p. 373-496, pIs. 1-36, 8
text-figs.
- - & EVITT, W. R. (1953): Silicified Middle
Ordovician trilobites. Ceol. Soc. America,
Mem., 59, 135 p. pIs. 1-33, 27 text-figs.,
2 tables ..

48
PROCEEDINGS OF THE PALAEONTOLOGICAL SOCIETY
OF JAPAN

13 *il1=.4'kI~~ 1975 if:l'f.$~ . if~lt,

1975 if 1· ....................... j',1ijw~ag . it!2!fw.cJ}5

J1 25 13 (±) . 26 13 (13) K.IEJl: f4~W4'kltB *tB(!to?: 1'ftl it ]IHK J::!f~ III) ve:.:f5l' -C I}fj Ill!. ~ .rtf-.:. (~9='$13 *,1JQ~ 110 ;g) 0~~:I1!!l/jX J::$~1=.W r¥iQtiilffLEE.1I::E~Jr.g7t· ................................• 1JQ~:@1:lt

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Marine plankton and sediments ve:.WJ-t 7.> -/y;f-:/?A:&lf~3@] Planktonic Conference ¥Ii~ ........................ 1§I33;eAA~5@]*A r'7::Z-?l"-/y;f-:/?A¥Ii~ ..... .

.................................. Ei/lt.JlEI*
~

:llt

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t!t~A: ;'fi11~:ti11i
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.................................. i\~ ag
J"IJ~ EE. 0) ~ 0) m~ c *lliiiltf!i!ive:. "':) l ' -C ....... .

· .. ·1iUJ133~. 1)g~{UlL . 1t*1?fft~ . 1§133~lE

J"l~m~tm~ C7E]t1![lm ............. . ;'fii/It.J:ti~lffLEE.O)~t/IJ~ -Elphidiidae O){9U~9=',c.., C L-C ................................
'1i.
:iltf'tlf;'fiO).:r. 'Y T Y Y·*ITiiO)tm~ve:. ",:)l' -C ..... .

a;*................................. ·fol~ilI!f=
f;[Y,(1I::E~*4O)mI~c.:cO)r~'{§,~ ............. .

· ........... W*:\!!I:=ft~ . j',1ijW~ag . j',1ij:WM~E
Late Cenozoic micropaleontologic events inthe equatorial Pacific sediments ..... .
.............. Y. TAKAYANAGI, T. TAKAYAMA, T. SAKAI, M. ODA and M. KATO
~1iUJW<;f§'&~ff~~ -t: 7 -/" yO) 7°'7 Y? r YiilffLEE.~Jr. ............

a;* '1i..

/~T11fhJ::$~1=.WO)f;[Y,(1I::E~

Jr.~B<.J~lM· ... j',1ij:WO~E • j',1ijW~ag . f€.133:k.&

Biostratigraphical significance of some productoid brachiopods from the Kashiwadaira Formation of the Abukuma
Mountains, Japan .................... .
......... . K. NAKA~IURA and H. KOIZUMIr;~

Ammonitology in Japan-a historical review· ......................... T. MATSUMOTO

7' P"7 -J::$~1=.W r¥iQtiilffLEE. {I::E~Jr.g

7t . ............................... f€.I33:k.&

ft1=.~il1

m:l'f.$-¥Ifh ~~Jllml/jXve:.:f5ft 7.> EFR~ T / 7° '7 Y
? r Y 1I::E'!l:f~0) If!ff(;EMr~ ............. .

-lMJft}[[O) ~iR®i£: r¥iQtiilffLEE.O) l'JTfive:. "':)
l'-C ................... ·j',1ij~D~E . f€.133:kf{
Eocene Larger Foraminifera collected by
dredge haul at the Amami Plateau,
northern margin of the Philippine Sea................................ r. KONDA,
K. MATSUOKA, A. NISHIMURA and T. ONO
Permian Bryozoa from Khao Hin Kling,near Phetchabun, North-Central Thailand ........................ S. SAKAGAMI
Giant fusulinid discovered from Iran ....
................ K. ISHil and M. MURATA
Studies on the genus Triticites from theMadre de Dios Island, in the southernpart of Chile ................ T. CHISAKA@!,(!Jli~,O)J::Jt*lIDO)SEM ve:..J::7.>tm~ .. t/iiI337¥1::f$~JIIW<i£:*.M1I::He:. ",:)l' -C ............. .
· ........... *~ JII'i1f;fO . t'~Ifh~l'if: . HEr"jlf!fle
13*fJ.JfJM~, l'nt1>7.> Hermanites ve:."':)l'-C. ................................. Ei/lt.JlEI*
13*0) "Balanus amphitrite" group ve:."':)l'-C··························.··· .. Wp~L

Pamirina ffiI1.O)7t~J::O)&ti:ve:."':)l'-C .. /J<ttJtlc
Toward a systematic catalogue of Mesozoic
Bivalvia from Japan .......... r. HAYAMI
Some evolutionary lineage of the Cenozoic
Radiolaria ............... " ..... T. SAKAI
J::$ijl(;133~i£:0) rock-boring shell fe:."':)l'-C ..
· ................................. t/ii1337¥1=.
Ligament ~{:¥tJ:-::,t-= Clinocardium (Fuscocardium) braunsi ve:.",:)l'-C ........ t/iiI337¥1=.
Some considerations on the phylogeny of

49
taxodontid Bivalvia ............ M. OMORI~;g~(;1)* 7.. l- :7 ::1 -:;((;1)5t:ffi ............. .
· .. .. .. .. . . .. . ......... iIfl.1'ifUl.Z.. :tE*r:re.~q--iJ- : 1" . l' :f.q--iJ- ::1"(;1).Itif!l(1=.fi~.!:fjlj:rI3'I*l1* ....
· , . . . . . .. ............ .rNR~1=.· lIlf,ill; r:r
1 :f.q--iJ- ::1":li!!ij[IY:J~~ CT$ID ......... ·+iRtl'1=.

The effect of the shell shape and asym·
metrical ridges of the shell ornamen·tation on burrowing of bivalves ..... .
· ......................... A. MATSUKUMA
Ontogenetic allometry and relative vari·ation in Scaphites planus YABE, an Upper
Cretaceous ammonite ........ K. TANABE

mi1\!:fl!!\'kJv::. giHf:l Lt-: }A;li€¥i;li€flit(;1)=.=$:v::.

'"?

l' --C ••..•...•...••••••••.•.••••... t~J~,3\?:Jo/l
W%W<iJJ;~(;1)<p!ifit!!:1&Wl:fl!!\'kJ./l'F............. .

....................... • ~~-ljj. :fl!H~~

ffiEBj(7U,ill; i§*,ill; . ~:IJIII'!S,ill;i.t(;1) ~=~c:fl!~ v::. '"?

"-c ............................ ·:fl!H;f1J~
Some conifer remains from the Paleogene
Noda Group, Iwate Prefecture, Japan ..
T. KIMURA and Y. KANSHA
Dictyozamites and some cycadophyte species
from the early Lower Cretaceous Oguchi
Formation, Tetori Supergroup, Japan ..
.............. T. KIMURA and S. SEKIDO
Evolutionary trends of the genus Acer inNorth America ....................... .
.............. T. TANAI and J. A. WOLFE
Scanning electron microscopic studies ofsome living and fossil "Quercus" pollen
grains in Japan ....................... .
.......... K. MATSUOKA and Y. MAEDA:tE~5ttJT iJ· G~t-: 7'C!ifit!!:v::.~ft G *~R~*:li!!:fjj!((;1) ~i*~~ . . . . . . . . . . . . .. . ........ Jltr ffi {Ji(:x50o 1974 ~ 1l fJ i:::.rrbn t-: 1975 . 1976 ~.!l:iWriiU\JK~O)~*, ?X.0)~t\"iM3~ U: (u"""f~f*Dlil, ABCooo1I~) ~r"j-!J3, ~ff m, ~n§m~, ~EB~i±, 7Eif~eB,)!7J( m, ~ifjf!J~, W1*&~IIii\, ,j,~R;~,~*• • , .~_~, • • ?X.~, ~.~~, Bif• • , ~* *.
1975~1 fJ 24 1300iWilN~fl.:i:::':}o~'-C, 1975 ·1976~~0)fl.::ljH:l:.t~*.eB, ~l%~~i:l:.~r"j-~(fl.:~),~i1Sm~ (m;1%) , ~EBIlit± (1¥li15 . *c.*J ~~), 7Eif~eB (m;1%) , )!7J( m (fff,1%) , W1*&*1Iii\(~5JIj.j}), ,j'~R;* (rr*) , ~;fgn~E' (11tEJ) , ~* * (fl.:W c'fP:."?t-:.
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1975 ~~ J: I) 0) Afl.:~H, i¥hifl.: ffit 10 15, :tE7i-fl.: ffit 115, ~t 1115 (U """f~~f*m*, A B CJI~). ~EB~-, John Davis HILL, -W~~rr, liiH8lf~, t~EB~~, i1S1iljJrf, i1Si'1 aB, jli';]iIF.j-~~, ~1itif?X. , :;k:ffH?X, ~EBmt~.
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1975 ~~J: I) ?X.O)~t\"iJ~~5JIjfl.: ffit CtJ: "? t-: (715)0 .!lI.~, 'HJz m, 1iifJ(:fC, ,*,1i*lC, :;k:lf!i1
m·Z, ~*~~, EBf1;;lEZ.
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1975 ~.!l:J: I) ?X.O)Ji I) i:::.fl.:!f1(iJ~{W:J:H'~n, fl.:f(IJO)~~ffil-B-{,~~~nt-:. -rfJifl.:~ 4, 000 P3, ~5J1joo~ffit5,600P3, :tE7i-fl.:~US$200
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t!\lIiX;) i:::.t!t~ ~n t-:o1975 ~.!l:'¥:vjq~!@J4:I:l:., ;j9)JEB'-f-t\" (J:ffilil1:f1;;IIfIi,@mO)liJf~), :}o J:LHt~;f,\!JIIw:=t\" (,*,ti'-t!tif/iFiI*J:It!l~0)i!!kf*;1lib4&.JO)il1:r~'¥:B9liJf~) i:::.t!t~ ~ n t-:.
JJ!E¥liO)JiIJ, *fl.: 1$[15' *c.*J 100.j}~ft*~~rrtd,j'~ffit~ (t~*.flB· ~~:l't, ~EBi>i±, il1li;fg1l~E', ~* *45-~ffit) iJ~~e,@ Lt-:iJ~, -t:O)*~c L. -C II3*O)il1:!f7l.1'¥:'j'5t'.J ~*x-c't±l!t!it-rG cci:::.tJ: "? t-:ot}])]ilfl- gJ(;t\", 1973 ~ 12 fJ 20 l3;err 13 *il1:4&.J'¥:fl.:¥li15*c.* 92 .j} 163~184 J{Jl)I.j~X;f,ifBX !Evolution andmode of life of Inoceramus (Sphenoceramus) naumanni YOKOYAMA emend., an Upper Cretaceous
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PALAEONTOLOGICAL SOCIETY OF JAPAN, SPECIAL PAPERS, NUMBER 20 '.i::' 19761f.l~n:
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53

CONSTITUTION
of theP ALAEONTOLOG ICAL SOCIETY OF JAPAN(Jan. 25, 1975)
Article 1. The Society shall be known as the Palaeontological Society of Japan.
Article 2. The object of the Society is to promote the study and popularization of palaeontology and related sciences.
Article 3. The Society, to execute Article 2, shall undertake the following business:
1. Issue the Society journal and other publications.
2. Hold or sponsor scientific lectures and meetings.
3. Popularize the science by field trips, scientific lectures and other projects.
4. Aid and encourage research work; award outstanding contributions to theSociety; carry out the objectives stated in Article 2.
Article 4. To attain the object of the Society, the Society may, by decision of the General
Meeting, establish within it research committees.
Article 5. The Society shall be composed of members who are active or interested inpalaeontology or related sciences.
Article 6. The members shall be known as Regular Members, Fellows, Patron and Honorary
Members.
Article 7. Persons desiring membership in the Society are requested to fill out the necessary
application forms and receive the approval of the Council.
Article 8. Fellows are persons who have held Regular Membership in the Society for morethan ten years, have contributed to the science of palaeontology, have been
nominated by five Fellows and approved by the Council.
Article 9. Patrons are organizations supporting Article 2 and recommended by the Council.
Article 10. Honorary Members are persons of distinguished achievement in palaeontology.
They shall be recommended by the Council and approved by the General Meeting.
Article 11. The members of the Society shall be obliged to pay the annual dues stated in
Article 12. Members shall enjoy the privilege of receiving the Society journaland participating in the activities stated under Article 3.
Article 12. The rates for annual dues shall be decided by the General Meeting. Rates forannual dues are: Regular Members, Yen 4,000; Fellows, Yen 5,600; and Foreign
Members, U. S. $ 20. 00; Patrons are organizations donating more than a share(Yen 10,000) annually; Honorary Members are free from obligations.
Article 13. The budget of the Society shall be from membership dues, donations and bestowals.
Article 14. The Society, by decision of the Council, may expel from membership persons who
have failed to pay the annual dues or those who have disgraced the Society.
Article 15. The officers of the Society shall be composed of one President and fifteen Councillors, among whom several shall be Executive Councillors. The term of office
is two years and they may be eligible for re-election without limitation. The
President may appoint several persons who shall be Secretaries and Assistant
Secretaries. An Executive Council shall be nominated and approved by theCouncil. Councillors shall be elected from Fellows by vote of returned mailunsigned ballot.
Article 16. The President shall be a Fellow nominated and approved by the Council. The
President shall represent the Society and supervise the business affairs. The
President may appoint a Vice-President when he is unable to perform his duties.

54
Article 17. The Society may have the Honorary President. The Honorary President shall berecommended by the Council and approved by the General Meeting. The Honorary
President may participate in the Council.
Article 18. The Society shall hold regularly one General Meeting a year. The President shallbe Chairman and preside over the administrative affairs. The program for the
General Meeting shall be decided by the Council. The President may call aSpecial Meeting when he deems it necessary. The General Meeting requires theattendance of more than one-tenth of the members. The President shall call aSpecial Meeting at the written request of more than one-third of the' members.
The request shall be granted only if the written statement fully explains thereasons for assembly and items for discussion.
Article 19. Members unable to attend the General Meeting may give as attending member
a written statement signed by himself trusting the bearer with the decision ofbusiness matters. Only one attending member may represent one absentee.
Article 20. The decision of the General Meeting shall be by majority vote. When the numberof votes is equal, the President shall cast the deciding vote.
Article 21. The President and Councillors shall compose the Council. The dicision of theGeneral Meeting concerning administration shall be considered and irriplemented
by the Council.
Article 22. The Executive Council shall carry out the decisions of the Council.
Article 23. An auditor shaH be elected by the Council from FeHows excluding Councillors
and Secretaries. The term of office is two years and he may be eligible forre-election.
Article 24. The fiscal year of the Society shaH begin on the first of January each year andend on the thirty-first of December of the same year.
Article 25. The amendments to the Constitution of the Society shall be decided at the General
Meeting and must be approved by more than two-thirds of those members whoare in attendance.
Addendum 1)

Voting in the Council shaH be by unsigned baHot.

lco and KOBAY ASH!:

Carboniferous conodonts from ltsukaichi

Plate 56KOIKE and ISHIB ASHI :Upper Triassic conodonts from Okinawa-jima

Plate 57

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\, ' 00Erratum:
Plates 56 and 57 in No. 96 should change places with each other, leaving their running
titles intact. For amendment, extra prints of the Plates are enclosed.

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84780 1'1j:)±~ .:E ~t 2 / 13ill~Transactions and Proceedings of the PalaeontologicalSociety of Japan

April 30, 1975

New Series No. 97

CONTENTS
TRANSACTIONS
Presidential Address
MATSUMOTO, Tatsuro: Ammonitology in Japan-A Historical Review.. .. .. . .

1643. MATSUMOTO, Tatsuro and KUWANO, Tadashi: A Find of Pseudocalycocem sfrom Hokkaido.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7644. MURATA, Masayumi and BAN DO, Yuji: Discovery of Late Permian Araxocem sfrom the Toyoma Formation in the Kitakami Massif, Northeast Japan 22645.

Hu, Chung-Hung: Ontogenies of Two Species of Silicified Trilobites from
Middle Ordovician, Virginia............... . .. ..... . ..... . .. ....... ...

32

PROCEEDINGS ....... . .. .. .... . ......... . .. ... ....... . .. . ................ . .. . .

48