MATERIALS AND METHODS

3.A. The usefulness of ostracods for the interpretation of the palaeoenvironments.

O stra c o d s are small a rth ro p o d s living in a bivalved shell o f lo w M g calcite, w h o se tw o valves are articulated by a dorsal hinge w hich allow s th em to o p en and close. T hey inhabit alm ost all aquatic environm ents (m arine and non-m arine ones) w ith m any different types o f form and this m akes them a very valuable to o l for ecological and palaeoecological studies.

T heir special position in the animal kingdom is becom ing b e tte r u n d ersto o d , bearing in m ind that they first appeared in C am brian tim es and their phytogeny can be traced to the R ecent. It is reasonable to assum e that, if a g ro u p o f organism s has been able to survive and distribute itself very successfully w orld-w ide for m o re th an h a lf a billion years, then this g ro u p has generally to be very flexible ecologically, in o rd er to g o th ro u g h any changes o f environm ental conditions and adapt to new ones. This is one point th at gives to o stra c o d s great advantages o v e r o th er fossil g ro u p s in L a te M iocene palaeoenvironm ents. Since o straco d s "inhabit" all aquatic environm ents, they are one o f th e few g ro u p s providing a continuous record before, th ro u g h and after th e M essinian Salinity Crisis.

M any o stra c o d o lo g ists consider that o stra c o d s are also useful for (at least local) biostratigraphical purposes. A very extensive w o rk in this direction has b een carried o u t by S IS S IN G H (1972, 1973, 1974, 1976, 1982) w ho divided th e L ate C en o zo ic o f th e E a ste rn M ed iterran ean into biozones based on o stra c o d s o f different facies (Fig. 15). H o w ev er, the usefulness o f o straco d s in biostratigraphy is not totally a c cep ted by researchers, since these organism s do not alw ays show the short-tim e evolutionary changes th at are observed in oth er fossil g ro u p s th ro u g h geological tim e. T he carapace m orp h o lo g y and th e species com position o f th ese organism s are also o ften strongly facies (i.e. environm entally) dependent as they are usually part o f the benthos. So, the stability o f their carapace m orphology and species com position u n d er specific environm ental conditions and the fact that a d ap tatio n to new ones is follow ed

Il

_ l CL

a

8 5 f t i r REL.8HALLOW MARINE WATER

REL. DEEP MARINE WATER CYPRIDEIS TOROSA TOROSA CYPRIDEIS cf. SARMATICA

AURILA SPEYERI SPEYERI

UROCYTHEREIS MARGARITFERA MARGARITiFERA LOXOCONCHA HODONICA CYTHERIDEA ACUMWATA ACUMWATA CYTHERIDEA PARACUMINATA VERRUCOSA A U RIA CONVEXA BA<VTH1AE CYTHERELLA VANDENBOLDI CYTHERETTA SEMIORNATA

Fig. 15: Tentative ostracod biozonation for the Late Cenozoic o f the South Aegean island arc (proposed by SISSINGH, 1972).

A ge

(n»y)

Ê ' #

—I--- 1--- 1--- 1---1—

3 6 9 LZ 15

PSYCHEOSPHAERIC / / / * • THERM O SPH AERIC

TEMPERATURE CC)

Fig. 16: Stratigraphie distribution of some ostracod genera in relation to the temperature conditions (after BENSON, 1976). D e p th A v 'O o - lva.*«K «nch« 1---1 ~ Abyssal Bathyal TEMPERATURE ("C)

Fig. 17: Open ocean depth/temperature zonation o f Mediterranean Neogene fossil ostracods (after BENSON, 1976).

by slight m orphological changes, leads to th e suggestion th at a system o f bioecological ra th e r th an biostratigraphical zones w ould be m ore reliable and successful for at least basinal stratigraphical use o f th ese organism s. Such an ap p ro ach to th e stratigraphie use o f o stra c o d s based in palaeoenvironm ental conditions, is given by B E N S O N (1976) w h o u sed tem p e ra tu re zo nations (Figs. 16 & 17).

3.B. Materials and methods

T he sam ples w ere disaggregated in boiling unbuffered C algon solution (S odium hex am etap h o sp h ate) and w ashed th ro u g h a 63 pm sieve. T he residue w as dry-sieved w ith 500 pm - 250 pm - 125 pm sieves and separated into fo u r fractions: > 500 pm, 500 -2 5 0 pm, 250-125 pm and 125-63 pm. E ach fraction w as th en subdivided (using a sedim ent splitter) into smaller, m anageable subsam ples ( o f ran d o m size), w ith each containing at least 300 intact o stra c o d s individuals.

Specim ens w ere picked, exam ined and identified using a Z eiss B R 6 stereo m icro sco p e. F o r th e identification o f the very sm all-sized specim ens and the ob serv atio n o f detailed m orphological ch aracters o f th e valves, a Z eiss D S M 940 Scanning E le ctro n M icro sco p e w as used. P h o to g ra p h s w ere also tak e n using th e S.E .M . F o r p h o to g ra p h y o f th e tran sp aren t specim ens, a Z eiss light cam era-m icroscope w as used. M easu rem en ts w ere m ade at first w ith a g rad u ated eyepiece scale in th e stereo m icro sco p e and w ere confirm ed later from th e S.E.M . p h otographs. F o r th e p h o to g ra p h e d specim ens, the num ber th at follow s th e letters “ S G ” rep resents th e specim en cata lo g u e num ber, w hile for the m easurem ents th e abbreviations L for length and H fo r height are used (in m icrons).

3.C. Review of the main studies dealing with Eastern Mediterranean ostracods that were most useful for this work

M any researchers have w orked on ostracods from the E astern M editerranean. An introduction o f their w orks and the help that they offered in this study is presented below. F o r the species identification firstly, am ong the m ost useful w orks w ere those of:

P U R I, B O N A D U C E and G E R V A S IO (1969), U L IC Z N Y (1969), B O N A D U C E , C IL IB E R T O , M A S O L I, M IN IC H E L L I and P U G L IE S E (1983), C A R B O N N E L (1 9 6 9 ), C A R B O N N E L and B A L L E S IO (1982), C O L E S and W H A T L E Y (1989), C O L E S , W H A T L E Y and M O G U IL E V S K Y (1 9 9 4 ), D A N A T S A S (1989), D A N IE L O P O L (1 9 7 6 ), K R S T IC and S T A N C H E V A (1989), N A ID IN A (1 9 8 9 ) and W O U T E R S (1970).

V ery useful fo r un d erstan d in g th e changing environm ents o f the M e d ite rran e a n w ith tim e w e re th e w o rk s o f V A N H A R T E N (1 9 7 8 -1 9 8 7 ) w h e re he explains and presen ts w ith detail th e o stra c o d faunas living in th e M e d ite rran e a n and th e changes th a t can observ ed to th ese faunas w ith the changing p a laeo g eo g rap h y and palaeoceanography. The w orks o f Z A N G G E R & M A LZ (1989) and Z A N G G E R (1991) w ere also useful since they clearly exhibit h ow by using Q uaternary ostracod faunas from selected areas o f G reece they reached paleoenvironm ental reconstructions, w hich w ere later used for archaeological purposes. T h e statistical p ro ced u res o f W H A T L E Y ’s (1 9 8 2 a and b) fo r using o stra c o d a fo r paleoenvironm ental analysis w ere also o f g reat help. A m ong his n u m erous w o rk s o n o stra c o d s and palaeoenvironm ents, th e w o rk o f B E N S O N (1976): T he ev o lu tio n o f th e O stra c o d e C osta A nalyzed by T h e ta-R h o D ifference, helped very m uch in u n d e rsta n d in g h o w th e changing in th e o stra c o d s th ro u g h tim e ta k e s place.

A p a rt fro m th e above w orks, th ere are also oth ers, w hich gave com bined inform ation and w e re u sed for identifications, b io stratig rap h y and palaeoecology. Such w o rk s are p re se n te d below :

G R A M A N N , F. (1 9 6 9 ) and G R A M A N N , F. and F. K O C K E L (1969) study the N e o g e n e o f th e S trym on B asin (N o rth G reece) and am ong th eir detailed palaeoenvironm ental in terp retatio n s they presen t o stra c o d s w hich are very sim ilar to the P a rate th y a n faunas.

S IS S IN G H , W . (1 9 7 2 a) studying th e L a te C enozoic O stra c o d a o f th e S o u th A egean Island, gives a d etailed acco u n t o f the o straco d s he d isco v ered in fo u r G re e k islands. In his bio stratig rap h y p a rt he attem p ts to establish an o stra c o d b io zo n a tio n schem e

(ten tativ e) fo r th e N e o g e n e o f th e E astern M editerranean, w hile in th e p alaeoecological p a rt he in tro d u ced a m ethod fo r evaluating d epth o f deposition and salinity. A lthough th e p resen t study has m any species in com m on w ith th o se o f S IS S IN G H (1 9 7 2 a), the lo w c o u n ts in the present w o rk w ere such, th at did not allow (at least com pletely) the rec o g n itio n o f th e ten tativ e biozones p ro p o sed by him.

A T H E R S U C H (1977) reviewed the genus U rocythereis from E urope and M editerranean redescribing m any species, defining similarities and differences am ong them and giving their geographic (w here possible) and palaeogeographic distributions. The same author later (1979) studied littoral ostracods from Cyprus, explaining their habitats and their prefered environments.

TSA PR A LIS (1 9 8 1) studied (Ph.D. Thesis) the ostracod fauna included in Pleistocene sediments o f Zakynthos island (Ionian Sea) giving at th e sam e tim e a very g o o d acco u n t o f th e palaeoenvironm ents.

M O ST A FA W I (1981) studied the Pleistocene ostracod fauna from the island o f K os, which he re-studied in 1986. In 1988 he studied the Plio-Pleistocene freshw ater ostracods o f K os and one year later (1989) the marine and nonm arine ones from R hodos island. All the above w orks o f this author am ong his many studies in various areas o f Greece, contain very good photographs o f ostracods and together form an im portant record o f the ostracods in the G reek islands o f the South Aegean.

R O M M E L T -D O L L (1990) studied the N eogene and Pleistocene ostracod fauna from cores o f Corinth Channel. This w o rk , apart from th e very interesting co m p ositions o f th e fauna th a t he reco rd ed , also presen ts a very detailed palaeoecological in te rp re ta tio n using statistical m ethods for b o th the o stra c o d s and th e sedim ent.

D O R U K (1973) studied th e L a te C enozoic o stra c o d s from th e B asins o f A d an a and A ntakya. A lthough in this w o rk little space is given to th e rec o n stru c tio n o f the palaeoenvironm ents, it has h o w ev er a very extensive taxonom ical part, extrem ely rich in g o o d quality S E M p h otographs. T hese are accom panied by age and distribution

in fo rm atio n fo r each species, w hich m ade this w o rk to be o f g rea t help fo r th e presen t study.

CHAPTER 4

TAXONOMY

4.A. Introduction

T he taxonom ic classification o f the o stra c o d s reco v ered during this study is p rese n ted in this ch ap ter and includes 410 species belonging to 105 genera. Since th e study is n ot intended to be prim arily taxonom ic o r b io stratigraphic, only the inform ation th a t is useful fo r ecological in terpretation is given here. F o r each species, fo u r ty pes o f inform ation are given:

1. Dimensions: this section contains the dim ensions o f every illustrated specim en. T hey are given in the form at o f tw o num bers separated by a com m a. T he first num ber c o rre sp o n d s to th e length o f th e valve and the second to the height. All th e dim ensions are in mm. Finally, the C atalo g u e num ber o f th e specim en is given in parentheses. 2. Distribution: the geographical and stratigraphical distribution o f the species in the M editerranean, as it is recorded by previous authors, in the following form at: age range: area (author, date o f publication). The age range is given as precisely as possible and for the correlation o f Paratethyan and M editerranean stages the diagram in Fig. 19 is used. This section can also be used in a sense as a synonymy list, in which how ever the inform ation is arranged in such a way that is m ore easily retrievable for the purposes o f the present study. 3. R e m a rk s : this section contains any additional information (e.g. new distributional data) that w ould be o f interpretative importance for this study. Also, any deviations from the original description as well as any similarities / relations with other species are discussed. F o r the subdivision o f the marine environments according to depth, the schem e appearing in Fig. 18 is followed. For the description o f environm ents in relation to salinity the following ranges (as they w ere decided in the Napoli O stracod Symposium (1967)) w ere followed:

H ypersaline (M arine) >40 7oo

Euhaline (M arine) 40-30 7%

Mixohaline (Brackish) 30-0.5 7oo

Limnic (Freshwater) <0.5 7oo

4. O ccu rren ce: the occurrence o f the species in the studied samples is given in this section. The samples localities and numbers are:

S E C T IO N S A M P L E S Polemi 10354-10365 Am argeti 10342-10351 & 10465-10468 Dhrym ou 9903-9930 Steni 9531-9540 Mari 9428-9443 Pissouri 9456-9473

(see also C hapter 2).

D E P T H