Ž .Journal of Marine Systems 15 1998 421–424

The Ponto–Caspian Zoogeographic complex of Cyclopoida in theCaspian, Azov and Black Seas

V.J. Monchenko )

Institute of Zoology NAS, Khmelnitsky str. 15, KieÕ-30, Ukraine

Revised 22 May 1997; accepted 26 September 1997

Abstract

Zoogeographical conclusions are drawn from several years of taxonomic study of the Cyclopoida of the Ponto–Caspianbrackish water region. The total Ponto–Caspian complex of Cyclopoida comprises 19 species of which 7 species areendemics to the Caspian provinces and 9 species to the mixohaline waters of the Black and Azov Seas, while 3 species arecommon to both areas. Of these 19 species 11 are of marine origin. The remaining ones are of freshwater origin. It is shownfor the first time that Cyclopoida of the Ponto–Caspian complex are also present in the Black and Azov Seas where theyoccur together at the same localities with representatives of this complex from other animal groups. As compared with theseother groups Cyclopoida show a higher proportion of species endemism in the Black and Azov Seas. Even a case of genericendemism among Cyclopoida is reported for the first time for these seas. q 1998 Elsevier Science B.V. All rights reserved.

Keywords: Cyclopoida; Ponto–Caspian complex; Black Sea; Caspian Sea

1. Introduction

Among the 178 species of Metazoa of thePonto–Caspian complex as listed by Mordukhai-

Ž .Boltovskoi 1979 to be present in the Black andAzov Seas no representatives of Cyclopoida werementioned. This did not agree with preliminary re-sults obtained by the author and raised the questionwhether Cyclopoida of Ponto–Caspian origin areindeed very rare or lacking altogether in the Ponto–Azovian basin, especially in its mixohaline waters.In order to elucidate this question the Cyclopoida ofa total number of 1988 samples from the Caspian,Black and Azov Seas have been determined. Amongthe species found 11 were new to science as were 4

) E-mail: vmon@iz.freenet.kiev.ua

of the genera. These taxa have already been de-scribed by the author in previous taxonomic and

Ž .ecological papers Monchenko, 1977a,b, 1979, 1986 .In the present contribution the Cyclopoida are anal-ysed for the first time from a zoogeographic point ofview and their importance for the solution of somegeneral zoogeographic problems concerning the evo-lution of the Ponto–Caspian fauna in the Ponto–Azovian basin is discussed.

2. Material and methods

The zoogeographic analysis of Cyclopoida in theCaspian Sea and the mixohaline waters of both theBlack and Azov Seas is based on the followingmaterial.

0924-7963r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved.Ž .PII S0924-7963 97 00090-0

( )V.J. MonchenkorJournal of Marine Systems 15 1998 421–424422

Ø 342 samples from the Caspian Sea collectedbetween 1967 and 1979 along the west and east

Žcoast down to the Iranian border mainly interstitial. Žsamples and along the north coast mainly meioben-

.thic samples ;Ø 776 samples from the holdings of Zoological

Institutes of the Russian Academy of Sciences takenbetween 1912 and 1936 from different parts of theCaspian Sea;

Ø 870 interstitial, meiobenthic and planktonicsamples collected between 1970 and 1983 in the

Ž .so-called limans estuaries of rivers discharging intothe Black and Azov Seas and in adjacent mixohalinewaters of both seas. Black Sea: Dnieper–Boug limanŽ . Ž .137 samples , Dniester liman 119 , Danube deltaŽ .440 , the mouths of 13 rivers along the Caucasus

Ž . Ž .coast 86 . Azov Sea: Miuss liman 39 samples ,Ž . Ž .Taganrog Bay 27 , Beisug liman 11 , the mouths ofŽ .4 small rivers 11 .

3. Results

Among the 32 species of Cyclopoida from theŽ .Caspian Sea 10 31% belong to the Ponto–Caspian

complex representing 2 chorological groups.Ø 7 species are endemics of the Caspian Sea

Ž .Table 1 . 6 endemic species had been describedŽ . Ž .earlier by Akatova 1935 and Lindberg 1942 ,

Ž . Ž .Lindberg 1951 , Lindberg 1952 . From these Para-cyclops dilatatus Lindberg must be excluded becauseit has been found in the meantime by the author inthe Dniester liman, but two have to be added, viz.

ŽCaspicyclops mirabilis Monchenko, 1986 from 4

.localities on the western shore , and SmirnoÕiellaŽunisetosa Monchenko, 1982 from the northern part

.of the Caspian Sea .The latter species belongs to a genus described by

Ž .Monchenko 1977a from the Dniester liman of theBlack Sea and represented there by S. reducta. To

Ž .this genus two species S. oblonga and S. robustaŽ .have here to be transferred which by Lindberg 1952

had been assigned to the genus Halicyclops. Theyboth have all the characteristic features of the genusSmirnoÕiella, in particular the second maxilla of theprehensile type which is unusual for Cyclopoida, andthe strongly reduced maxilliped consisting of onlyone small joint with two weakly developed setaewhich is unique among Cyclopoida.

Ø 3 species found in the Caspian Sea as well as inone or several localities from the mixohaline watersof the Black or Azov Seas from which species ofPonto–Caspian origin had previously been unknowndespite hundreds of publications on Cyclopoida ofthe Black and Azov Seas. To this group belongsParacyclops dilatatus as mentioned above. It hasbeen found in the Dniester liman at salinities be-tween 0.55 and 1.1‰. Also to this group belongsCryptocyclopina inopinata Monchenko, 1979 whichrepresents the first record of the family Cyclopinidaein the Caspian Sea and which has been found inter-stitially at two localities on its west coast at salinitiesbetween 10.0 and 11.5‰ as well as on the east coastof the Black Sea near Sukhumi at 7.9‰. Finally theoligohaline species Diacyclops cf. clandestinusŽ .Kiefer which the author considers a sibling speciesof the freshwater form widely distributed in thewestern Palaearctic belongs to this group. It lives

Table 1Species composition of the Ponto–Caspian Cyclopoida

Endemics of Ponto–Azov Common species for both seas Endemics of Caspian Sea

Halicyclops Õalidus Monchenko, 1974 Cryptocyclopina inopinata Monchenko, 1979 Halicyclops sarsi Akatova, 1935H. cryptus cryptus Monchenko, 1979

Ž .H. cryptus secundus Monchenko, 1982 S. oblonga Lindberg, 1951Ž .SmirnoÕiella reducta Monchenko, 1977b Paracyclops dilatatus Lindberg, 1952 S. robusta Lindberg, 1951

Colpocyclops dulcis Monchenko, 1977a S. unisetosa Monchenko, 1982Ž . Ž .C. longispinosus Monchenko, 1974 Eucyclops orthostylis Lindberg, 1952

Ž .Eucyclops persistens Monchenko, 1978 Diacyclops cf. clandestinus Kiefer, 1926Diacyclops insularis Monchenko, 1982 Caspicyclops mirabilis Monchenko, 1986

Ž .Speocyclops cf. demetiensis Scourfield, 1932 Cyclops furcifer caspicus Lindberg, 1942

( )V.J. MonchenkorJournal of Marine Systems 15 1998 421–424 423

interstitially at 5.8‰ salinity along the west coast inthe south of the Caspian Sea as well as in the mouths

Ž .of 8 rivers at salinities between 1.6 and 5.9‰ onthe Caucasus coast of the Black Sea.

The mixohaline waters of the Black and AzovSeas are inhabited by 53 species of Cyclopoida.According to their halopathy and distribution pat-terns these species can be divided into the followingthree groups.

.1 Marine euryhaline group—2 species of thegenus Oithona of which O. similis Claus has aworldwide distribution while O. minuta Kritschaginis widely distributed in the Atlantic Ocean.

.2 Freshwater group—39 species to be divided intwo subgroups: 26 species must be regarded as acci-dental records in mixohaline waters while 13 speciesare euryhaline and able to form permanent popula-tions in the mixohaline waters. The species of bothsubgroups are widespread in continental freshwaters.

.3 Mixohaline group—12 species which havemainly disjunctive distributions and are confined intheir occurrence to river mouths or the seashore nearthese mouths.

4. Discussion

Halopathy and distribution patterns of the speciesof the latter group are a good indication that theybelong to the Ponto–Caspian complex. There arefurther arguments to corroborate this assumption.

Ž .Three species of the group see Table 1 occur inboth the Caspian as well as the BlackrAzov Seas.They may have migrated from the Caspian Sea to thePonto–Azov basin in times when both were inter-connected as happened repeatedly.

SmirnoÕiella reducta from the Dniester limanŽ .salinity 1.10–2.29‰ belongs to a genus repre-sented in the Caspian Sea by 3 species. Its actualarea of distribution and halopathy give reasons tobelieve that it arose in the basin that preceded theBlack Sea. The same may apply to the genusColpocyclops of which C. longispinosus occurs in

Ž .the Dniester average halopathy here 4.35‰ as wellŽ .as the Dnieper–Boug limans 2.18‰ while C. dul-

Ž .cis is known from the lower Dnieper only 0.5‰ .Colpocyclops is closely related to the Ponto–Caspiangenus SmirnoÕiella as evidenced by the modified

palp of the maxilulle, the prehensile type maxilla,Žand the reduced maxilliped which in the case of

.Colpocyclops is completely absent . Both generabelong to the marine subfamily Halicyclopinae.

The following two species are related to Halicy-clops magniceps Lilljeborg which is widely dis-tributed in the oceans of the eastern hemisphere.Both species are confined to the mixohaline watersof the Black and Azov Seas. Among them H. Õalidus

Žhas quite a disjunctive area of distribution Danubedelta, Dniester liman of the Black Sea, Miuss liman

.of the Azov Sea and its halopathy is 2.7‰–6.4‰.These facts suggest that it is a Ponto–Caspian speciesand its geographically widely separated localitiesindicate that it may have been widely distributed all

Žalong the northern coast of the Neo-Euxine and.perhaps even the Ancient-Euxine basin which ac-

Ž .cording to Starobogatov 1986 and other authorscited by him had a salinity of about 6–8‰. Of thespecies Halicyclops cryptus the subspecies cryptushas been recorded from the interstitial of the AzovSea near the town Mariupol at a salinity of 6.4‰. Itco-occurs there with H. Õalidus and other members

Ž .of the Ponto–Caspian complex see below . Thesecond subspecies H. cryptus secundus was discov-ered in a well of the town Novoeconomichnoye inthe northern part of the Azov Sea.

Among the species of freshwater origin Diacy-clops insularis inhabits the interstitial in the banks ofthe mouths of 10 rivers on the Caucasus coast of theBlack Sea at salinities between 1.62 and 5.95‰.This halopathy and wide disjunctive distribution arecharacteristic for members of the Ponto–Caspiancomplex. The same applies to Eucyclops persistensrecorded from the mouths of the rivers Psezuapseand Kintrishi on the Caucasus coast at salinitiesbetween 0.5 and 1.4‰. At last Speocyclops cf.demetiensis has to be mentioned. All the other species

Ž .and subspecies of this genus about 40 inhabit sub-terranean waters of the mountains of alpic formationfrom the Pyrenees to the east Caucasus. Speocyclopscf. demetiensis has been recorded from the mouthsof 6 rivers along the Caucasus coast of the Black Seaat salinities between 1.7 and 2.0‰, while the purelyfreshwater species S. demetiensis has been found atfour localities in the Caucasus mountains.

In summary it can be said that the Ponto–Caspiancomplex of Cyclopoida is represented not only in the

( )V.J. MonchenkorJournal of Marine Systems 15 1998 421–424424

Ž .Caspian Sea 10 species but as shown here also inŽ .the Black and Azov Seas 12 species . In these seas

the Cyclopoida occur together with representativesof the Ponto–Caspian complex of other animalgroups and show the same characteristics as, e.g.,Limnoclethodes behningi Borutzky, Schizopera ne-

Ž .glecta Akatova, Hypania inÕalida Grube ,Ž .Dikerogammarus haemobaphes Eichwald and other

Amphipoda, Pterocuma rostrata Sars, LimnomysisŽ .benedeni Czerniavsky .

The total Ponto–Caspian complex of CyclopoidaŽ .consists of 19 species Table 1 . Of them 11 are of

Žmarine origin family Cyclopinidae; family Cyclopi-.dae, subfam. Halicyclopinae , the remaining ones of

Žfreshwater origin family Cyclopidae, subfam. Eucy-.clopinae and Cyclopinae . From a zoogeographic

point of view it can be said that three of these 19species are distributed throughout the Ponto–Caspianbrackish water region while 7 species are restrictedin their occurrence to the Caspian Sea and 9 speciesto different mixohaline areas of the Black and Azov

Ž .Seas Table 1 . It is interesting to note that theproportion of the Ponto–Azovian subcomplex in re-lation to the total Ponto–Caspian complex of Cy-

Ž .clopoida is rather high—12 species out of 19 63% .As to the other Metazoa this proportion is only 42%Ž178 species out of 425, Mordukhai-Boltovskoi,

.1979 . Also the species endemism in the Ponto–ŽAzovian basin is higher in Cyclopoida 75%, 9

.species out of 12 than in all other Ponto–CaspianŽ .Metazoa 4.3% . This could be due to a rather recent

invasion of this fauna from the Caspian Sea someŽthousand years ago Mordukhai-Boltovskoi, 1960,

.1979 .An interesting fact is the generic endemism of the

genus Colpocyclops in the Ponto–Azovian basin.Such a case has not been reported before. It can bespeculated that the two known species of the genuswere formed in two different basins that preceded

Žthe Black Sea, C. dulcis now inhabiting oligohaline.waters of the lower Dnieper in the Ancient-Euxine-Žbasin and C. longispinosus now occurring in the

meiomesohaline zone of the Dnieper–Boug and the.Dniester limans in the Neo-Euxine-basin.

Summing up it can be said that a complicatedgeological history of the basins in question, differentconditions of salinity in the different basins preced-ing the actual seas and different faunistic sourceshave contributed not only to the presently observedspecies and generic endemism but also to faunisticpeculiarities in the different parts of the Ponto–Caspian basin. Cyclopoida have much to tell in thereconstruction of the history leading to the presentsituation and they have become an important groupwhen it comes to elucidate the zoogeography of theSouth Russian seas and the natural history of theirfauna.

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