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Chapter 79. Palaeocene non-marine ostracods in China
1148 S. Z. GUAN
important members are similar to those of the Porpocypris-Cypridea-Parailyocyprisassemblage.
Since the above fossils have been found in different sections, some species may have come from
the Upper Palaeocene strata.
Fifty-eight species of 25 genera have been reported from the Taizhou Formation, the important
members of which are Cypridea (Cypridea) jloribunda Chen, C. (C.) orbinoda Chen, C . (C.)
semimorulu Chen, C . (C.) hebes Chen, C . (C.) modihebes Chen, C. (C.) vitrea Chen, C . (Morinia)
xindianensis Hou, C. (Pseudocypridina) subtera Hou, Ilyocypris huangqiaoensisYang, Parailyocypris
taizhouensis Yang, Porpocypris orbiculata Guan, P. sphaeroidalis Guan, Disapontocypris tralatitia
Chen, Quadracyprisfavosa Hou, etc. (Hou et al., 1982). As regards the age of the Taizhou Formation, there are different opinions. Some geologists assign it to the late Cretaceous, while others put
it in the Late Cretaceous to Palaeocene or the Palaeocene. Although the genus Cypridea, which
was in its acme in the Early Cretaceous, includes over twenty species in the Taizhou Formation, the
majority of them exhibit a unique aspect as indigenous forms which occur only in the border area
of Jiangsu and Zhejiang Provinces. Other species, such as those of the genera Porpocypris, Parailyocypris and Ilyocypris, as well as Cypridea (Pseudocypridina) subtera Hou, C. (Morinia) xindiaensis Hou, C. (Guangdongia)sp. etc., have also been found in the Shanghu Formation. Most of them
continue to occur in the overlying 1st Member of the Palaeocene Funing Formation. However,
on the evidence of the sporopollen and charophyte floras found in association, a Palaeocene age
for the Taizhou Formation is most likely.
TABLEDISTRIBUTION OF LATEPALAEOCENE OSTRACODS IN CHINA.
astracoda f o s s i l
along Yanqti R .
Shungta F o r .
'langsu N Jlangsu Basln Funinq F o r .
h r J lang H m 9 J tahu a r c a Chanqhc 0. I - 2 F .
Palaeocene Non-marine Osrracods in China 1149
2) The Late Palaeocene ostracods represented by the Sinocypris excelsa-Parailyocypris changzhouensis-Eucypris hengyangensis assemblage include among their main elements, such species as
Sinocypris excelsa Guan, S. funigensis Ho, Parailyocypris changzhouensis Yang et Hou, Eucypris
hengyangensis Guan, E. subreticulata Guan, E. stagnalis Mandel, Cyprinotus xialiushiensis Guan,
C. libitus Guan, Limnocythere nemegtensis Szczechura, Metacypris changzhouensis Chen and so on.
Some species of Sinocypris in this assemblage are similar to Hemicyprinotus watsonensis Swain and
H . watsonensis emacinta Swain from the Palaeocene to Lower Eocene strata of the Western United
This assemblage is extensively distributed in China and is basically identical in taxonomic
composition at many different localities as in the Xinzhuang Formation of the Sanshui, Dongwan,
Longgui and Heyuan Basins, the Liushagang Formation of Leizhou Peninsula and Beibu Wen of
Guangdong, the Shangyang Formation in the Hepu Basin of Guangxi, the Chijiang Formation in
the Chijiang Basin of Jiangxi, the Chashanao Member of the Xialushi Formation in the Hengyang
Basin, the Gaocun Formation in the Yuanma Basin, the Doumu Formation in the Dongting
Basin of Hunan, the Gongjiachong Formation in the Jianghan Basin of Hubei, the Yuguangpo
Member of the Mingshan Formation in the western Sichuan Basin, the 2nd to 4th Members of the
Funing Formation in Jiangsu, the Shuangta Formation along the Yangzi River of Anhui, the 3rd
and 4th Formation of the Changhe Group in the Hangjiahu district of Zhejiang as well as in
Xichuan, Linbao of Henan, Yunnan, Qinghai(?) and other places (Table 1). This indicates that
these had a similar palaeoenvironment during Late Palaeocene time.
OF THE PALAEOCENE OSTRACODS
The Palaeocene is the first geological period in the Tertiary. Therefore, as a fauna coming into
existence at the turning point from Mesozoic to Cenozoic in geological history, the Palaeocene
ostracods must show the coexistence of both Mesozoic and Cenozoic taxa with the genera flourishing in the Late Mesozoic gradually declining to their extinction. Those genera having their
origin in the Early Cenozoic gradually developed to dominate the fauna. For example, the genus
Cypridea, originating in the Middle Jurassic and flourishing during the Early Cretaceous, declined
in Late Cretaceous times and finally became extinct in the Late Palaeocene (China)or Early
Eocene (United States). The genus Bennelongia (DeDeckker et al., 1981) living today in
Queensland, Australia is probably a descendant of Cypridea in that remote part of the world.
Among the species of Cypridea in the assemblage, Cypridea (Pseudocypridina) subtera has already been found in the Upper Cretaceous Jinjiang Formation of the Yuanma Basin, the Paomagang Formation of the Jianghan Basin, and the Daijiaping Formation of the Hengyang Basin.
Cypridea (Morinia) nanixongensis and C. (Pseudocypridina) rigida show a close resemblance to
the Late Cretaceous C.(M.) xindianensis Hou and C. (P.) giganrea Ye. In the Shanghu Formation,
for example, the number of individuals of Cypridea make up about 25% of the total number of
ostracods found in it (Guan, 1978).
Talicypridea, which enjoyed its heyday of development in the Late Cretaceous, already has 42
known species of which only two have been discovered in the Palaeocene Nalanblag Formation
of the People’s Republic of Mongolia and the Mengyejing Formation of Yunnan in Southwestern
Porpocypris is an endemic genus, having only been found in Southeastern China where it occurs
mainly in the Early-Middle Paleocene strata, although individual species occasionally appear in the
Upper Cretaceous, as in the Paomagang Formation of the Jianghan Basin and the Fensuiao Fsrmation of the Dongting Basin.
1150 S.Z. Gum
Zlyocypris, Parailyocypris, Cypris, etc. originated in the Cenozoic, Zlyocypris and Cypris becoming
highly developed and diverse since Palaeocene times with many of their species widespread in
various Recent non-marine water bodies all over the world.
To sum up, this assemblage exhibits aspects of coexistence, namely a transitional character
between the Mesozoic and Cenozoic ostracods and differs both from the Late Cretaceous Talicypridea-Cypridea-Candona assemblage and the Late Palaeocene Sinocypris excelsa-Parailyocypris
changzhouensis-Eucypris hengyangensis assemblage.
In the Late Palaeocene, the ostracod fauna underwent a rapid change. Cypridea and Talicypridea,
well developed in the Late Mesozoic, and Porpocypris, flourishing in the Early-Middle Palaeocene,
no longer existed. However, Sinocypris, Parailyocypris, Ilyocypris, Sinometacypris, which were only
living in the Cenozoic, and Eucypris, Cyprinotus, Limnocythere, which were mainly living in the
Cenozoic, gained a dominant position. The Late Palaeocene ostracod fauna shows a closer relationship in terms of genera and species composition with the post-Palaeocene ostracod fauna than
with the Early-Middle Palaeocene ostracod fauna.
OF OSTRACODS IN THE PALAEOCENE
From the Mesozoic to the Cenozoic a distinct change took place in the ostracod fauna. Some
old genera and species became extinct and a lot of new forms came into being. Their evolutionary
relationships are shown in Text-fig. 1.
Rhinocypris, ranging from the Late Jurassic to Cretaceous on the Eurasian continent, disappeared by the end of the Cretaceous. It was characterised by its small-sized carapace, inconspicuous
dorsal sulcus and weak reticulation on the valve surface. Parailyocypris and Ilyocypris are
considered to be two lineal descendants of Rhinocypris. The former has a large carapace, broadly
ovate in side view with a shallow dorsal sulcus, on both sides of which large nodes are developed.
Ilyocypris possesses a medium-sized carapace, rectangular in lateral view, distinct dorsal sulcus,
well developed dorsal and ventral nodes and reticulation on the valve surface. The geological
range of Parailyocypris is from the Paleocene to Early Eocene, while Ilyocypris ranges from the
Early Tertiary to Recent. The latter rests on the soft mud on the bottom of lakes and ponds and
was one of the most common non-marine genera in the Cenozoic.
Cypr 1 s
Cypr I dea
Rhi nocypr is
1-Evolution of Palaeocene Ostracods.
Palaeocene Non-marine Ostracods in China 1151
The main characteristic feature of Cypridea is its anteroventral beak. In order to distinguish the
various forms of Cypridea, a number of subgenera have been identified. In the early Late Cretaceous, an evolutionary change in the beak of the subgenus Cypridea (Cypridea) took place resulting in the occurence of the cristate protuberance or lip-like structure of Talicypridea. The genus
Talicypridea, established and discribed by Khand, 1977, existed over thirty million years, most
species dying out at the end of the Late Cretaceous with only a few survivors continuing to exist
in the Palaeocene. The genus Cypris ranges from the beginning of the Tertiary to Recent times.
It has been supposed that Talicypridea was an intermediate form between Cypridea and Cypris
on the basis of the lip-like structure developed at the anterior end of the Cypris carapace which
is similar to that of Talicypridea, and according to the geological range of the two genera, Cypris
appeared as a successor of Talicypridea. However, Cypris, which is subtriangular in lateral view and
subglobose in dorsal view, differs distinctly from Talicypridea, which is subrectangular in side view
and wedge-shaped in dorsal view. Judging from the ontogeny of Cypris (Guan, 1984), its early larval
shell shows no relationship with Talicypridea. Thus Cypris must originate directly from Cyprideu.
The subgenus Cypridea (Bisulcocyprideu) has two parallel transverse sulci in the dorsal part and
flourished in the Cretaceous period. Its immediate descendant is probably Cypridea (Guungdongiu)
Guan, 1978, which has three transverse sulci arranged in a radial pattern in the dorsal part.
Nanxiongium (namely Quadracypris) probably originates from one of the unbeaked types of the
genus Cypridea (Hou, 1983).
Sinocypris, which has a medium-sized shell, is ovate in lateral view with a shallow depression in
the central anterior part of the valve and a smooth or reticulate valve surface. It bears a strong
resemblance to Nanxiongium, except that the carapace of Sinocypris is larger with the surface reticulation not well developed. As regards the time distribution, Nanxiongium reached its maximum
development mainly in the Late Cretaceous while Sinocypris appeared at the beginning of the
Tertiary. Thus Sinocypris may be considered to have originated from Nanxiongium.
Porpocypris is characterised by its small carapace, subcircular in lateral view and swollen in its
central part, which sometimes looks likes a bubble or sometimes forms a node, and by a narrow
frill along the anterior margin. Judging from the aspect of outline and anterior frill, Porpocypris is
similar to Cyprois. Cyprois appeared in the Late Cretaceous and flourished in the Cenozoic while
Porpocypris existed mainly in the Palaeocene, so the latter is probably a descendant of Cyprois.
From the evolutionary relationships between the genera discussed above, the following conclusions may be drawn:
1) Increase of shell size is one of the evolutionary trends of genera in the same lineage.
2) The shell ornamentation of descendant forms is more developed than that of their ancestors.
3) The specialization or extreme development of the valve structures of an ostracod may lead to
its extinction as is probably the case with Tulicyprideu which had a large crest-like protuberance at
the anterior end of the right valve, Porpocypris with a strong central swelling which forms a bundle
or node, and Parailyocypris which had a wide thick and heavy shell with bulky nodes and spines.
4) Most of the above mentioned genera belong to the Order Podocopida, Superfamily
Cypridacea. All of them possess simple hingement and inner lamellae which remain almost
unchanged from ancestral to descendant forms. This pehnomenon is probably due to the calm
environment in non-marine water bodies with weak hydrodynamic energy, which are inhabited by
1152 S. Z. GUAN
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Biostratigraphy of Paleogene Non-marine
Ostracoda from East China
Nanjing Institute of Geology and Paleontology, Academia Sinica, Nanjing, P . R . China,
Amoco Production Company Research Center, Tulsa and University of Delaware, Newark, U.S.A.
In eastern China, five non-marine ostracode zones can be recognized from the Paleocene to
the Oligocene. These are discussed and compared with Paleogene ostracode assemblages in the
western United States. Two of the assemblages can be subdivided into freshwater non-marine and
marginal marine or saline lake types.
Non-marine sediments deposited during the Early Tertiary in East China consist mostly of
detrital clastics and localized carbonates and evaporites that have yielded abundant endemic
ostracode faunas, These show; (1) definable assemblages, (2) obvious stratigraphic and lateral
facies changes, and (3) significance in bath stratigraphic subdivision and correlation of the
Early Tertiary subsurface oil-bearing strata. Problems of correlation and assemblage relationships exist in all the faunas to be discussed. Correlation between China and North America are
based on generic similarities. Many of the Chinese taxa may be congeneric with the more broadly
defined North American genera, but only the first author has seen both the Chinese and the North
American taxa. Solution of these problems will aid in the exploration for petroleum in the widespread Cenozoic rocks of East China (Text-fig. 1). Comparison of Chinese material with North
American material is necessary to resolve these problems.
AND CORRELATION OF ASSEMBLAGES
From Paleocene to Oligocene, five stratigraphically significant ostracode assemblages are
recognized. Further, the Late Eocene and Oligocene assemblages can be subdivided into nonmarine and marginal marine or saline lake ostracode subassemblages (Text-fig. 2). They are given
I. Porpocypris subglobra-Parailyocypris taizhouensis-Cypridea (Cypridea) xindianensis assemblage of the Paleocene.
11. Sinocypris funingensis-Cypris farosa-Eucypris stagnalis-Parailycypris changzhouensis-Limnocythere spinisalata assemblage of the Early Eocene.
D.s. VANNIEUWENHUISE AND F. M.SWAIN
1154 J. D.HE,
ASSEMBLAGE I I
ASSEMBLAGE IVl B
ASSEMBLAGE lV2 0
in East China from which ostracode assemblages were obtained.
111. Echinocypris fabaeformis-Cyprinotus
(Heterocypris) jianglingensis assemblage of the
IV, Non-marine type : Cyprinotus (Heterocypris) macronefandus-Cyprinotus (Heterocypris)
igneus assemblage of the Late Eocene.
IV2. Marginal marine type: Cyprinotus (Heterocypris) yongningensis-Austrocypris levisChinocythere subcornuta assemblage of the Late Eocene.
V,. Non-marine type : Cyprinotus (Cyprinotus)hubeieniss-Cyprinotus (Heterocypris)jinheensisPinnocypris postiacuta assemblage of the Oligocene.
V,. Marginal marine type : Hebein ia-Huabeinia-Dongyinia- Candona-ParachinocytheveChinocythere assemblage of the Oligocene.
Assemblage I was first found in the Shanghu Formation of the Nanxiong Basin in 1964 (Guan,
1978). During the Paleocene, the most abundant and widespread Mesozoic forms, such as Cypridea and Talicypridea species, dwindled and vanished. They were replaced with similar Cenozoic
genera, Cypridea (Cypridea) xindianensis HOU,1978, C . (Guangdongia) speciosa Guan, 1978, c.
(Pseudocypridina) subtera Hou, 1978, Parailyocypris taizhouensis Yang, 1982, Ilyocypris sub-