Tải bản đầy đủ - 0 (trang)
Chapter 20. A preliminary study on ornamentation and ultrastructure of Mesozoic and Cenozoic Ostracoda in China

Chapter 20. A preliminary study on ornamentation and ultrastructure of Mesozoic and Cenozoic Ostracoda in China

Tải bản đầy đủ - 0trang

236 Y.T.Hou AND Y. H. ZHAO



ostracod shell was started in the later of 1970’s. The junior author, in his master thesis (1981)

and his doctoral dissertation (1984) (both in press), described shape of pore canals of some

ostracods, established five types of ultrastructure of carapace, and discussed the relationship

between the trace elements in shell and the palaeoenvironment, in which the ostracods once lived.

Recently greater attention has been paid by Chinese ostracod researchers to shell ornamentation and pore ultrastructure of ostracods collected in China. This paper deals with a large

TABLETYPES OF OSTRACOD ORNAMENTATION

A. Reticulate type

1. Polygonal reticulate type

2. Granular ridge-like reticulate type

3. Transverse bar-bearing reticulate type

4. Polyform reticulate type

5. Round reticulate type

6. Scale-like reticulate type



C. Echinulate type

1. Spine-like echinulate type

2. Granular echinulate type

D. Striate type

1. Corduroy-like striate type

2. Fingerprint-like striate type



B. Spot-shaped type

1. Punctate ornamented type

2. Measles-like ornamented type



TABLET TYPES OF OSTRACOD

PORES



A. Types of simple pores

1. Single circular pores

2. Double circular pores

3. Lip-like circular pores

4. Funnel-shaped circular pores



B. Types of sieve pores

1. Round sieve pores

2. Elongate or irregular sieve pores



amount of material which has been studied by many Chinese ostracod workers and published

in the past thirty-odd years. The present writers make use of the holotypes and homotypes described and illustrated in these publications, amounting to more than 500 species and nearly 1,OOO

individuals of Mesozoic and Cenozoic non-marine or marine Ostracoda, which were examined by

means of the scanningelectron microscope. From several thousand scanning electron microphotographs they observed that the ornamentation of the shell and the ultrastructure of the pores show

many patterns and consider that both kinds of patterns may be divided into twelve and six types

respectively (see Tables 1 and 2).



PLATE1-Fig.



1. Limnocytherenodosa Bojie, Polygonal reticulate ornamentation, Bar=lO pm. Fig. 2. Paracandona

euplectella (Robertson), Granular ridge-like reticulate ornamentation, Bar = 10 pm. Fig. 3. Limnocythere

bucerusu Sou, Transverse bar-bearing reticulate ornamentation, Bar = 100 pm. Fig. 4. Leucocythereplena

Y.H. Zhao, Polyform reticulate ornamentation, Bar = 10 pm. Fig. 5. Cypridea favosa Ye, Round reticulate

ornamentation, Bar = 100 pm. Fig. 6. Cypridea? dissonu Netchaeva, Scale-like reticulate ornamentation,

Bar = 100 p m . Fig. 7 . Camarocypris ovata Bojie, Punctate ornamentation, Bar = 30 pm. Fig. 8 . Sinocypris

funingemis Ho, Measles-like ornamentation, Bar = 100 pm.



Ornamentation and Ultrastructure of Ostracoda in China 239



TYPESOF SHELLORNAMENTATION

Reticulate types

1. Polygonal reticulate type, with surface ornamentation composed of polygonal reticulation.

Meshes very shallow and flat, as in some species of the genera Limnocythere, Chinocythere and

Ilyocypris. especially clear in Limnocythere bicostata Bojie, L. microcostata Bojie, L. longipileiformis Bojie, L. nodosa Bojie, L . dectyophora Bajie (Pl. 1, fig. 1).

2. Granular ridge-like reticulate type, possesses reticulateridges consistingof many micrograins

arranged in regular order; reticulation generally appearing in pentagonal or hexagonal shapes

as in Paracandona euplectella (Robertson) (Pl. I , fig. 2).

3. Transverse bar-bearing reticulate type, with meshes rather irregular, rhomboidal, hexagonal

or sub-quadrate in shape and unequal in size; each mesh with a transverse bar, which may be longer or shorter, as in Limnocypridea bucerrusa Sou, L. inflata Ye and Ilyocyprimorpha netchaevae

s u (Pl. 1, fig. 3).

4. Polyform reticulate type, bearing a lot of secondary ornamentation in the shape of

five-pointed stars or six to seven or three to four round pits in each irregular reticulate mesh, as

shown on the surface of Limnocythere (Xinanolimnocythere) tribulosa Y.H. Zhao, Leucocythere

plena Y.H. Zhao and Abrotocythere quadracornis Y.H. Zhao (Pl. 1, fig. 4).

5. Round reticulate type, with round meshes spreading all over the surface, sometimes slightly

oblong in shape, often varying in size and area between adjacent meshes. All these features are usually

observable in genera such as Cypridea, Ilyocyprimorpha, Limnocypridea, Huabeinia, Quadracypris,

Talicypridea, etc., and occasionally in a few species belonging to the genera Tuozhuangia and Chinocythere. Species which are considered to show the typical ornamentation include Cypridea bella

Chen, C. favosa Ye, C. fuyuensis Ding, C . (Cypridea) semimorula Chen, C . (C.) cellularia Chen,

Ilyocyprimorpha magnijica Liu, Z. sungarienensis Ten, Limnocypridea datongzhenensis Ye,

Huabeinia huidongensis Bojie, H. postideclivis Bojie, Tuozhuangia alispinata Bojie, Chinocythere

xinzhenensis Bojie, etc. (PI. 1, fig. 5).

6 Scale-like reticulate type, ornamented with scale-shaped reticulation arranged densely on

the surface and observable in such species as Cypridea? dissona Netchaeva (Pl. 1, fig. 6).



Spot-shaped types

1. Punctate ornamented type, with many punctate pits over the whole surface of the valves,

with Camarocypris elliptica Bojie, C. ovata Bojie as representatives of this pattern (Pl. 1, fig. 7).

2. Measles-like ornamented type, shell surface completely covered by a number of very small

round punctuations. Sinocytheridea latiovata Hou et Chen, S. longa Hou et Chen and Sinocypris

funingensis Ho are representative (Pl. 1, fig. 8) of this type.



Echinulate types

1. Spine-like echinulate type, with a great number of small spines distributed over the surface;

RATE

2-Fig. 1. Dongyingiu impofitaBojie, Spine-like echinulate ornamentation, Bar = 30 pm. Fig. 2. Cyprideo

(Sebastianites) tumidu Ho, Granular echinulate ornamentation, Bar = 100 pm. Fig. 3. Ziziphocypris rugosu

(Liu). Corduroy-likestriate ornamentation, Bar = 100 pm. Fig. 4. Berocypris substriatuBojie, Fingerprint-like

striate ornamentation, Bar = 30 pm. Fig. 5. Metacypris aphthosa Y.H. Zhao, Single circular pore, Bar = 1

pm. Fig. 6. Cypridopsis caohaiensis Y.H. Zhao, Double circular pore, Bar = 1 pm. Fig. 7. Ilyocypris neoaspera

Huang, Lip-like circular pore, Bar = 10 pm. Fig. 8. Candonu dafiensisHuang, Funnel-shaped circular pore,

Bar = 1 pm. Fig. 9. Cythere futeu futeuO.F. Muller, Round sieve pore, Bar = 10 pm. Fig. 10. C'ushrnunidea

japonica Hanai, Elongate or irregular sieve pore, Bar = 10 pm.



240



Y.T.HOU AND Y.H. ZHAO



Dongyingia impolita Bojie and Ilyocyprimorpha inandita are representative of this pattern (PI. 2,

fig. 1).

2. Granular echinulate type, decorated with many small grain-like tubercules over the whole

surface, with Cypridea (Sebastianites) tumida Ho as the typical example (Pl. 2, fig. 2).



Striate types

1. Corduroy-like striate type, with curved, continuous and disconnected striations present on

the surface, as observed in the non-marine species Ziziphocypris rugosa (Liu), 2 . simakovi (Mandelstam) and the marine species Perissocytheridea trapeziformis Hou et Chen, as far as known

(Pl. 2, fig. 3).

2. Fingerprint-like striate type, bearing curved striations rather like fingerprints, sometimes

branching or with two merging into one; distance between two striae unequal-as shown on the

surface of Berocypris substriata Bojie, B. striata Bojie and Virgatocypris striata Bojie (Pl. 2, fig. 4).



TYPESOF OSTRACOD

PORES

Types of simple pores

1. Single circular pores. Pores round in shape, simple, and evenly distributed; size and space

between pores variable in different genera and species, usually found on the surface of many ostracod species collected from non-marine strata in China, with Candona and Metacypris as very

typical patterns (Pl. 2, fig. 5).

2. Double circular pores. Pores appearing doubly-circular in form, connected with one another around a common centre, as in Cypridopsis caohaiensis Y.H. Zhao and Cyclocypris persicaria

Y.H. Zhao (Pl. 2, fig. 6).

3. Lip-like circular pores. Pores appear to have a collar-like flange under high magnification,

quite commonly occurring in non-marine ostracod species observed under the SEM, as in Chinocythere, Limnocythere, Ilyocypris, etc. (Pl. 2, fig. 7).

4. Funnel-shaped circular pores. Pores on the surface appear somewhat funnel-like. and are

only found in a few non-marine ostracod species, such as Candona daliensis Huang (Pl. 2, fig. 8).

Types of sieve pores

1. Round sieve pores. Pores circular in shape, with a large one in the centre or near the

margin but absent in a few species; different in size and arrangement with different species and genera. So far only found in marine ostracods such as Perissocytheridea trapeziformis Hou et Chen,

Neocytherideis convexa Hou et Chen, Sinocytheridea latiovata Hou et Chen, S. longa Hou et Chen,

Chthere lutea lutea. O.F. Muller, Eucythere sp., etc. (Pl. 2, fig. 9).

2. Elongate or irregular sieve pores. Pores appearing elongate or irregular in shape, often

in association with circular sieve pores on the same shell surface, as in Cushmanideajaponica Hanai

(Pl. 2, fig. 10).



SUMMARY

AND CONCLUSIONS

Summing up all the types of ornamentation and pore ultrastructure mentioned above, the writers

here put forward their preliminary views:

1. Types of surface ornamentation can be similar to each other in different species of the same

genus or of different genera.



Ornamentation and Ultrastructure of Ostracoda in China 241



2. Although some fossil ostracods can be found in different sedimentary conditions in different

areas, their ornamentations bear obvious similarities to each other.

3. In general, similar ornamentation may occur in different species of the same genus distributed in different geological ages. For example, the geological range of Limnocythere is from

Tertiary to Recent, but the ornamentation of different species in this genus is commonly polygonal

reticulate. On the other hand, a close relationship exists between some species of Cypridea and

some species of Talicypridea or Quadracypris, both of which possess the same kind of ornamentation belonging to the round-pit reticulate type.

4. Although the type of ornamentation varies in different parts of the same shell surface, as

seen in Limnocypridea succinata Ding and Neocytherideis convexa Hou et Chen, the variation is

stable in different individuals of the same species, as in Limnocythere (Xianolimnocythere) trilubosa

Y.H. Zhao and Abrotocythere quadracornis Y.H. Zhao.

5. Types of pores are obviously different between Ostracoda collected from marine strata and

from non-marine strata. They are probably not influenced by the type of ornamentation, but may

be controlled by sedimentary facies, or more specifically, by salinity.

From a macroscopic view, it seems that the variation in ostracod ornamentation is not controlled

by the factors of time and space, but possibly caused by some factors in the organism itself. Preliminary assessment of the large amount of material described in this paper reveals that there is

probably a close relationship between the character of ostracod ornamentation and their evolution and therefore the study of shell ornamentation would provide evidence not only for evolutionary affinity, but also for their classification. It is especially significant in dealing with the problems of ostracod classification and evolution. The results of observations on the samples suggest

that the different pore types are closely linked with sedimentary conditions such as salinity, etc., SO

the type of pore can be considered as one of the indicators for determining the sedimentary facies

and conditions under which the ostracod lived.

To sum up, the type of ostracod ornamentation may reflect the relationship between some

genera and their evolutionary processes,while the type of pore is probably related to the sedimentary

facies. The study of both these features would accumulate more material and evidence leading to a

much wider field for ostracod researchers in the future.



ACKNOWLEDGEMENTS

We wish to express our thanks to Mr. Yuan Liu-ping for technical assistance and to our colleagues who supplied homotypes.



REFERENCES

D ~ P ~ ~ C HP.E1982.

,

Ultrastructure of the wall



of two living ostracods,Herpetocypris chevreuxi (Sars) and Pontocythere

elonguta (Brady), in comparison with fossil ostracods from the Middle Jurassic of Normandy. I n BATE, R.H.,

ROBINSON, E. and SHEPPARD, L.M. (eds.). Fossil and Recent Ostracods, 61-74. Ellis Horwood Ltd. Publishers, Chi-



Chester.



(4,



HANAI, T. 1970. Studies on the ostracod subfamily Schizocythereinae Mandelstam. J. Paleont. 44

693-727.

KEYSER, D. 1983. Ultrastructure of carapace-sensilla in Aurilu convexa (Baird, 1850) (Ostracoda, Crustacea). In MAD

DOCKS, R.F. (ed.). Applications of Ostracoda,649-658. Department of Geosciences, University of Houston, Hou-



ston, Texas.



-1982. Development of the sieve pores in Hirschmunnia viridis (0.F. Miiller, 1785). I n BATE, R.H., ROBINSON, E.

and



SHEPPARD, L.M.



(eds.). Ostracods, 51-60. Ellis Horwood Ltd. Publishers, Chichester.



242 Y.T. How AND Y.H. ZHAO

w. 1973. zur Ultrastruktur, Mikromorphologie und Taphonomie des Ostracoda-Carapax. Palaeontographica Abt. A, 144 (1-3). 1-111.

OKADA, Y. 1982a.Structureand cuticleformation of the reticulated carapaceof the ostracodeBicornucythere bisanensis.

Lethaia, 15 (1). 85-100.

-1982b. Ultrastructure and pattern of the carapace of Bicornucythere bisanensis (Ostracoda, Crustacea). In

HANAI, T. (ed.). Studies of Japanese Ostracoda. Univ. Mus., Univ. Tokyo, Bull., 20, 229-255.

-1983.Ultrastructure and functions of pores of ostracodes. In MADDOCKS, R.E. (ed.). Applications of Ostracoda,

640-648. Department of Geosciences, University of Houston, Texas.

PURI, H.S. 1974. Normal pores and the phylogeny of Ostracoda. In BOLD, W.A. VAN DEN, (ed.). Ostracoda, the H.V.

Howe Memorial Volume. Geoscience and Man, 6, 137-151.

- and DICKAU, B.E. 1969.Use of normal pores in taxonomy of Ostracoda. Trans. Curf Coast Assoc. Geof.Sac.,

19,353-367

ROSENFELD, A. and VESPER, B. 1976.The variability of the sieve-pores in recent and fossil species of Cyprideis torosa

(Jones, 1850)as an indicator for salinity and palaeosalinity. In L~FFLER,H. and DANIELOWL, D. (eds.). Aspects of

Ecology and Zoogeography of Recent and Fossil Ostracoda, 55-67. Junk, The Hague.

LANGER,



Ultrastructure of Myodocopid Shells

(Ostracoda)

I.G. SOHNAND LOUISS. KORNICKER

U.S. Geological Survey, Washington,D.C. and

National Museum of Natural History, Washington, D.C.,U.S.A.



ABSTRACT

Based on the study of scanning electron micrographs of cross-sections of ostracod shells representing 17 species in genera of the suborders Cladocopina, Halocypridina, and Myodocopina, five

primary components are identified in the endocuticle: 1-laminate, 2-columnar, 3-fine granular,

4-coarse granular, 5 -homogeneous. Crystalline nodules, rare in vivo, but common in preserved

specimens, are considered to represent a secondary component. Preliminary experimentation with

sun-dried shells of Vargula hilgendorfi indicates that crystalline nodules form in 10% buffered formalin, a commonly used preservative of plankton. Examination of two growth stages of this

species suggests the same general combination of components during ontogeny.

Pelagic species of Gigantocypris, Halocypris, Conchoecia, and Macrocypridina have laminate

endocuticles, but the pelagic Codonocera polygonia has both laminate and coarse granular components in the endocuticle. Benthonic species may have only one or a combination of any of the

five components, but not more than four components in a species.

Based on this and previous studies, the ultrastructures of the endocuticles of the following taxa

are known: Metapolycope hartmanni, Polycope sp., Conchoecia atlantica, C. valdiviae, C . belgica,

Halocypris injlata, Thaumatoconcha caraionae, T. tuberculata, Asteropterygion setiferum, Macrocypridina castanea, Gigantocypris muelleri, Scleroconchafolinii, Vargulahilgendorfii, Codonocerapolygonia, Eusarsiella texana, E. disparalis, Spinacopia sp.



INTRODUCTION

The purpose of this study is to examine cross-sections of the shells of myodocopid ostracods

with scanning electron microscopy (SEM) in order to determine their ultrastructure. We report

on the ultrastructure of 17 species in the suborders Cladocopina, Halocypridina, and Myodocopina, and we identify five different primary components in the shells (Table 1); crystalline nodules

are considered to be a secondary component. The combinations of the various components of the

shells are discussed relative to taxonomy and environment.



METHODS

Scanning electron microscopy techniques in the National Museum of Natural History were re243



244 I.G. SOHN AND L.S. KORNICKER



TABLE

1-SHELL ULTRASTRUCTURE

AND HABITAT

OF MYODOCOPA



Suborder CLADOCOPINA

Metapolycope hartmanni Kornicker and

van Morkhoven, 1976

Polycope sp.

Suborder HALOCYPRIDINA

Conchoecia atlantica (Lubbock, 1856)

C. belgica Muller, 1906b

C . valdiviae Muller, 1906a

Halocypris inflata (Dana, 1849)

Thaumatoconcha caraionae (Kornicker

and Sohn, 1976)

T. tuberculata Kornicker and Sohn, 1976

Suborder MYODOCOPINA

Asteropterygion setiferum Kornicker and

Caraion, 1974

Codonocera polygonia Poulsen, 1962

Eusarsiella disparalis (Darby, 1965)

E. texana (Kornicker and Wise, 1962)

Gigantocypris muelleri Skogsberg, 1920

Macrocypridina castanea (Brady, 1897)

Scleroconcha folinii (Brady, 1871)

Spinacopia sp.

Vargula hilgendorfii (Muller, 1890)



Kornicker and van Morkhoven, 1976

fig. 7d.

Herein, P1. 2, fig. 4.

Herein, P1. 1, figs. 6-9; P1. 2,fig. 5.

Bate and East, 1972,fig. 10; 1975,PI. 3,

fig. 8.

Bate and Sheppard, 1982,P1. 7, figs. 1,2.

Bate and Sheppard, 1982,P1. 4, fig. 4;

P~s.5-10.

Herein, PI. 4, fig. 7.

Herein, PI. 4,figs. 8-10.

Herein, PI. 1, figs. 1 0 , l l ; Kornicker,

1975,figs. 17, 18.

Bate and Sheppard, 1982,PI. 2, fig. 5.

Herein, PI. 4,figs. 3-6; PI. 5, figs. 14,15.

Herein, P1. 5, figs. 7-9.

Herein, PI. 1, figs. 1-5; Harding, 1965,

fig. 8.

Herein, PI. 2,fig. 1 ; Bate and East, 1975,

P1. 3, figs. 9, 10.

Herein, PI. 2, figs. 2, 3.

Herein, P1. 5, figs. 10-13.

Herein, PI. 2,figs. 6-8; P1. 3,figs. 1-7;

P1. 4., figs.

1.2.

-



(X = present, - = absent, B = benthonic, P = pelagic)



cently described (Sohn, 1983, p. 10). Except for those specimens of VurguZa hiZgendorfi (Muller,

1890) that were sun-dried as soon as collected, the specimens prepared for scanning electron microscopy had been preserved in alcohol. The sun-dried specimens were fractured by pressing with

a thick needle, and the fragments were mounted on stubs for study. The wet specimens were either

PLATE1-Figs. 1-5. Gigantocypris muelleri Skogsberg, 1920.USNM 151241A. 1,2,section made by cryofracture

to show laminae, approx. x 1,450and x 5,800,respectively. Area of 2 shown by arrow on fig. 1. Figs. 3-5,

torn sections of the same specimen, approx. x 470, x 1,500,and x 4,700,respectively. Arrow on fig. 3 indicates

epicuticle; area of 5 shown on fig. 4 by arrow; outer surface of valve towards bottom of plate. Locality 1.

Figs. 6-9. Conchoecin atlantica (Lubbock, 1856). Adult male, left valve, USNM 149290.6,7,cut sectionsnear

dorsal margin above incisur of valve showing laminae, approx. x 2,000 and x 4,500, respectively. Adhering

objects are bacterial contamination during preparation. Sections oriented with outer surface of valve towards

top of plate. 8,9,cut section in other area behind midlength at midheight of same fragment, approx. X 2,200

and ~4,500,

respectively. Area of 9 shown by arrow on fig. 8; laminae separated during preparation. Sections

oriented with outer surface of valve towards top of plate. Locality 2. Figs. 10, 11. Asteropterygion setiferum

(Kornicker and Caraion, 1974). Adult female, right valve sliced with razor blade, USNM 143996.10,epicuticle

(arrow) and part of laminated endocuticle, showing that elongate process is confined to epicuticle, approx.

X 5,100.11, detail showing laminae, approx. x 9,800.Sections oriented with outer surface of valve towards

top of plate. Locality 3.



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Chapter 20. A preliminary study on ornamentation and ultrastructure of Mesozoic and Cenozoic Ostracoda in China

Tải bản đầy đủ ngay(0 tr)

×