Fishes of the Caspian Sea: Zoogeography and Updated Check-List

ZOOSYSTEMATICA ROSSICA, 18(2): 295–317 25 DECEMBER 2009

Fishes of the Caspian Sea: zoogeography and updated check-list

A.M. NASEKA & N.G. BOGUTSKAYA

N.M. Naseka & N.G. Bogutskaya, Laboratory of Ichthyology, Zoological Institute, Russian Academy of Sciences, Universitetskaya Emb. 1, St. Petersburg 199034, Russia. E-mail: [email protected]

Geographic distribution of some 350 taxa from the Caspian and Black Sea basins were analyzed with regard to recent taxonomy, phylogeny, endemicity and ecological classification. A check-list of the Caspian Sea fishes (taxa from families down to subspecies) is provided. Eighty species and subspecies permanently occur or occasionally recorded from the North Caspian while 33–35 species and subspecies being only distributed in the Middle and South Caspian. Forty-four species are common for the two ecoregions. A comparison of the Caspian and the Black Sea fish faunas and their historical evolution is given with special respect to palaeogeography and palaeohydrology of the basin. Key words: Caspian Sea, fishes, evolution, zoogeography, taxonomic composition

INTRODUCTION arguments for this water body being a true lake and not a sea. However, the Caspian The Black, Azov, Caspian and Aral seas, biotic diversity clearly reflects its relation- remnants of the intracontinental Paratethys ship to the Caspian geological history as an basin, possess a spectacular diversity of the isolated basin of the world ocean, and also biota. The term “Paratethys” was coined a complex process of immigration from the by Laskarev (1924) to designate the string Mediterranean and Atlantic Ocean. of epicontinental basins originally stretch- ing from the Alps to what was the Aral Sea that has been separated from the rest Physical environment of the Caspian Sea of the Tethys by the uplift of the Alpine- A number of publications summarise Caucasian mountain chain since the Early much of the literature about the geomor- Oligocene. Many groups of aquatic organ- phological structure and hydrology of the isms including fishes have radiated in this Caspian Sea, e.g. Kosarev & Yablonskaya region (e. g. Mordukhai-Boltovskoi, 1979; (1994), Mandych (1995), Golubev (1997), Dumont, 1998). Diversification in the Para- tethys has been traditionally linked to iso- Mamaev (2002), Reid & Orlova (2002), lation events from the Mediterranean and Coad (2008). Below we briefly overview the Atlantic and Indian Oceans resulted in only those features which has the most sig- restricted marine, brackish lacustrine, and nificant impact on recent diversity and dis- freshwater lacustrine environments, and in- tribution of fishes – salinity and its gradient, duced the evolution of endemic species and depth, seafloor morphology, and tempera- higher taxa among molluscs, ostracods, fish, ture – in two major ecoregions of the Caspi- and other groups of animals (e. g. Băcescu, an Sea (for the ecoregions, see Bogutskaya, 1940; Zenkevich 1963; Starobogatov, 1970, 2007 and Naseka & Bogutskaya, 2007). 1994; Bănărescu, 1991; Jones & Simmons, The Caspian Sea lies between 47°13´ 1996, 1997; Dumont, 2000). and 36°34´35´´ north latitude and between It has been debated in literature if the 46°38´39´´ and 54°44´19´´ east longi- Caspian Sea is really a sea though freshened, tude. Statistics for the Caspian Sea (Ma- or just a giant lake. Dumont (1998) presents maev, 2002): surface area approximately

390,000 km2, water volume 78,700 km3, ing the North and Middle Caspian is the coastal length 7,000 km, average depth Mangyshlak Threshold, which is structur- 208 m (184 m by other sources), maximum ally connected to the submerged Karpin- depth 1,025 m. The Caspian Sea catchment ski Ridge on the western coast and to the area is about 3.5 million km2. The length of Mangyshlak mountains of the eastern coast. the Caspian (north-south) is approximately The North Caspian Sea is thus bordered in 1,200 km. The greatest breadth of the Cas- the south by a traverse from Chechen’ Island pian from east to west is 466 km; in the re- to the Tyub-Karagan Cape, and Mangysh- gion of the Absheron Peninsula, its breadth lak Bay. The eastern part of the Precaspian is only 204 km. The average breadth of the [Prikaspiiskaya Nizmennost’] Lowland is Caspian from the west to the east is 330 km. also included. This area represents the for- These figures vary to a considerable extend mer shallow bays of the Caspian Sea, which for the sea level is changing. The Caspian were covered by water to a greater or lesser Sea’s size varied during the Quaternary extent until the beginning of the 20th cen- Period. During the glacial epoch the sea tury; since 1930–1945 the area has dried decreased because of the decline of flow completely. However, the coastline is again throughout the basin. However, during the changing due to recent water level increas- post-glacial Khvalyn transgression its level es. The ecoregion also includes the entire was approximately 50 m higher than oceanic Volga Delta. The place of separation of the levels, or 75 m higher than current levels. At Buzan branch is regarded as the area where that time waters of the Caspian Sea spread the Volga Delta begins. From there the far north and occupied the entire Caspian Volga River is split into a dense network of Lowland; the area of the sea was nearly two arms and anabranches. The Volga River del- times as large as it is now. The highest water ta is one of the largest deltas in the region. level, -22 m, was reached about 38,000 years The numerous arms, anabranches, island, ago, but may have been as low as – 64 m. and sand ridges (Baer’s hillocks) occupy an The water level averages -27.66 m over the area of more than 13,000 km2. Within the past 2,500 years (Dumont, 1998). Early in limits of the Volga River are a great num- the last century (up to 1929), the sea level ber of lakes. These are the so-called ilmens fluctuated around -26.2 m, later decreasing and polois of the Volga Delta; their number to -29.0 m in 1977 and to -29.02 m in 1978 totals around 1,000. Ilmens of the delta are (Kosarev & Yablonskaya, 1994). In 1978 a relatively more resistant, and partly retain rapid rise began, the level reaching -27.0 m water even during dry periods, whereas by 1994. Since 1995 some regression has polois exist only during spring floods. In been observed in the sea level. total, the Northern Caspian covers about The huge basin of the Caspian Sea is mor- 80,000 km2. It is relatively shallow, averag- phologically split into three parts: 1) a north- ing about 5–6 m in depth. The Ural Fur- ern shallow part (less than 10 m), separated row is a slightly deeper (8–10 m) structure from the middle by a line passing from the es- extending the Ural River trend across the tuary of the Terek River to the Mangyshlak shallow northeast shelf. Being much shal- Peninsula; 2) a middle part, with an average lower than the Middle and South Caspian, depth of 200 m and a maximum depth of 790 the Northern Caspian contains only 1% of m; and 3) the southern and deepest section, the Caspian’s total volume. The Volga River with a maximum depth of 980–1025 m and contributes up to 82% of the inflow. Salinity average depth equal to 325 m. in the North Caspian varies markedly, from The northern part of the Caspian Sea is 0.1 parts per thousand (ppt) at the mouth on the margin of the Pre-Caspian synclino- of the Volga and Ural rivers to up to 10–11 rium of the Eastern European platform. ppt near the Middle Caspian. The size and South of this geological feature and divid- position of the mixing zone varies with the

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA 297 volume of Volga River outflow and some- Caspian is very steep, with the eastern slope times covers almost the whole area of the running deeper and wider than the western northern Caspian Sea (Katunin, 1986). slope. The deepwater South Caspian hol- The Middle and South Caspian are nat- low is bounded by depths of 800–900 m: in urally separated from the shallow Northern the north it appears to project between two Caspian. The Middle Caspian floor has a submarine ridges. To the south the undula- heterogeneous geological structure. The tions gradually disappear and the bottom Derbent Depression, the western portion levels off over most of the hollow. Between of the shelf, and the continental slope are the hollow and the Apsheron Rift are two part of the marginal synclinorium trough ridges that extend in a south-southwest of the Great Caucasus. The Apsheron Rift direction, and reach 200–250 m above the (or Threshhold) dividing the South and water level. The middle and southern parts the Middle Caspian is a structure formed of the sea have only small fluctuations of sa- as a continuation of folded structures of the linity; surface salinity is about 12.6 to 13.5 Great Caucasus, part of the alpine fold re- ppt, increasing from north to south and gion. The continental slope, shelf, and the from west to east. There is also a slight in- bottom of hollows are prominent in the deep crease in salinity with depth (0.1 to 0.2 ppt) parts of the sea in the Middle and South observed in all regions of the sea. The Kara- Caspian, and submarine ridges are promi- Bogaz Gol which is situated on the eastern nent in the South Caspian. Thus, in terms coast of the Caspian Sea and bites deep into of geomorphology the Middle Caspian is a the hinterland is hypersaline. hollow, bounded by the Mangyshlak Rift in Water temperature in the Caspian Sea the north and by the Apsheron Rift in the varies considerably with latitude. This south. According to some authors, the deep- difference is greatest (about 10°C) in the water part of the Caspian is a combination winter when temperatures in the north are of three hollows. The deepest is the Derbent 0–0.5°C near the ice and 10–11°C in the hollow with a flat bottom that is slightly in- south. Freezing temperatures are found clined to the southwest. The shelf is the nar- in the north and in shallow bays along the rowest (up to 11 km) and the continental eastern coast. The water temperature of the slope is the steepest (up to 1°) around Der- west coast is generally 1–2°C higher than bent and Divichi. The shelf expands to the along the east coast. In the open sea, the south, and the continental slope becomes water temperatures are higher than those declivous. Tectonic uplifts in the form of near the coast by 2–3°C in the Middle Cas- banks and islands line the shelf around the pian and by 3–4°C in the southern part of Apsheron Peninsula. The average depth of the sea. the Middle Caspian is 215 m. The shelf oc- cupies 56% of the area of the Middle Cas- Palaeogeography pian; its edge lies at approximately 100 m in depth. In the South Caspian which is The border between the Mediterranean separated from the Middle Caspian by the and Paratethyan bioprovinces was dynamic; Apsheron Rift, forty-six percent of the area in extreme cases, the Mediterranean com- lies on the shelf at depths up to 100 m. The pletely invaded the Paratethys (as in some shelf of the western coast south of the Ap- periods of the Early Miocene), or Parat- sheron Peninsula has many banks, islands, ethyan waters drained into the dry Medi- and mud volcanos. The most dissected part terranean basin, as it is supposed for some of the eastern shelf is the one adjoining intervals in the Messinian. Thus the his- Cheleken. South of Cheleken is Ogurchin- tory of the Paratethyan basins has been an skii Island, Ulski Bank, and Gryaznyi Vol- involved story of opening and closing con- cano. The continental slope in the South nections (towards each other and the Medi-

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 298 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA terranean), catastrophic transgressions, and and Indian Ocean. The Paratethys region episodes of desiccation (Schulz e al., 2005). is divided into a western and eastern Parat- There is a big number of publications dis- ethys, which are separated from each other cussing palaeogeography and palaeohydrol- by the Carpathian mountain range. The ogy of the Caspian Sea, some most recent are western Paratethys formed in the back (to those by Benson (1976), Nevesskaya et al. the north and west) of the Alpine–Car- (1986), Rögl (1998, 1999), Meulenkamp et pathian belt and comprises the Pannonian al. (2000), Vasiliev et al. (2004, 2005), Pop- and Transylvanian basins (Austria, Hun- ov et al. (2004, 2006). Palaeontological data gary and NW Romania). The eastern Para- were widely used in publications discussing tethys developed in the Alpine–Carpathian the Caspian fauna composition and its evo- foredeep and consists of the Dacian, Euxin- lution, e. g. those by Starobogatov (1994), ian and Caspian basins. The Black Sea and Dumont (1998, 2000), Aladin & Plotnikov the Caspian Sea are the actual brackish wa- (2000), Reid & Orlova (2002). We are not ter remains of this ancient water mass. intending to provide a full review of the Throughout its past, short episodes of issue but try below to emphasize some as- abrupt salinity rises as a result of saline in- pects which may be critical for understand- fusions from neighbouring marine waters ing of the Caspian fish fauna transformation were followed by a slow return to brackish through the history of the Paratethys. conditions. The first isolation event of the During the Mesozoic and early Ceno- Paratethys, indicated by the appearance zoic, the Eurasian and African continents and abundance of endemic molluscs, took were separated by a large oceanic basin place in the late Early Oligocene (Rupelian, called the Tethys. Global plate tectonic Kiscellian, Solenovian). The second such processes caused a northward motion of the Paratethys-wide isolation event happened African plate with respect to Eurasia and during the late Early Miocene (Burdigalian, led to continental collision and the gradual Ottnangian, Kozahurian), and the third in closure of the Tethys Ocean. These tectonic the late Middle Miocene (Serravallian in movements generated the elevation of the the Mediterranean, Sarmatian s. str. in the Alpine–Himalayan mountain belt, which Central Paratethys, Volhynian in the East- started to act as an E–W striking barrier ern Paratethys) (Schulz et al., 2005; Popov since the beginning of the Oligocene. Con- et al., 2004, 2006). During the late Miocene, sequently, the Tethys Ocean evolved into the continental Estern Paratethyan basin two different domains, the Mediterranean evolved into the Sarmatian which developed basin to the south and the Paratethys to 9–9.9 million years ago (Mya) (Semenenko, the north. The Mediterranean remained an 1987; Steininger et al., 1996) into the slight- open marine basin because the connection ly brackish Pontian basin. The most usual to the Atlantic guaranteed the exchange correlation proposes correspondence of the of water masses and organisms, permitting Maeotian with the Middle–Upper Torto- a direct biostratigraphic correlation to the nian, and Pontian with the entire Messin- world’s oceanic record. The Paratethys be- ian (Iljina & Nevesskaja, 1979; Rögl, 1998). came semi-isolated with brackish to fresh This correlation was supported by abso- water environments that led to the devel- lute age data (Chumakov, 1993): 9.3 Mya opment of endemic faunas and different for the lower boundary of the Maeotian, biozonations. In addition, ongoing tecton- 8.0–8.4 Mya for the Lower/Upper Maeo- ics caused a fragmentation of the Paratethys tian boundary, 7.1 Mya for the Maeotian– into various subbasins, which were affected Pontian boundary, and 5.2–5.3 Mya for up- by a continuous changing of the water sur- per boundary of the Pontian (Popov et al., face extent and of the water connections 2006). However, the Neogene chronology between subbasins and the Mediterranean of the eastern Paratethys is poorly defined.

Ages of stages can easily vary by more than est one in the history of the Eastern Para- 1 or 2 million years between different ba- tethys) transgression (Akchagylian, around sins and different studies: a good example 3.4–1.8 Mya) which resulted in an inflow is the Pontian Stage for which estimates of of oceanic water, probably from the Persian the duration vary from 3.0 Mya to 0.3 Mya Gulf (Zenkevich, 1963). It is commonly (Vasiliev et al., 2004). The Early Pontian supposed that this oceanic influence had basin was strongly enlarged, especially by a devastating effect on the brackish water transgression along its northern and eastern fauna of Pontian origin in the Caspian ba- margins. Deep-water environments existed sin, but only a minor effect on the Kujalni- only in the Black Sea and South Caspian cian (Black Sea) basin though the brackish- depressions. Based on the prevailing brack- water Akchagilian basin was connected ish fauna, the salinity of the basin was low, with the Euxinian depression through the but it did not fall under 5–8 ppt (Popov et Kuma-Manych Straight. However, recent al., 2004). A pronounced regression started data show that the salinity at the beginning at the beginning of the Late Pontian (Por- of the Akchagilian was about 20–25 ppt and taferrian and Babadzhanian), and the Cis- then decreased to 5–12 ppt due to large in- caucasian Strait was closed, separating the flow of fresh waters. Caspian Basin from the Euxinian Basin. The The successive basins since about 1.8 eastern lake-sea became restricted to the re- Mya (Apsheron, Baku, Khazar, and Khva- cent Middle and South Caspian depressions, lyn) that followed the Akchagilian basin including the Kura Gulf. This fall in sea level were also brackish water reservoirs and approximately corresponded in time with a experienced large water level and salinity drastic sea level drop in the Mediterranean changes (Aladin & Plotnikov, 2000). Caspi- (5.7–5.6 Mya). The salinity of Late Pontian an and Euxinian basins had repeated inter- Lake remained at the level of 10–15 ppt, connections through Pleistocene (Svitoch, however in Babadzhan Lake, due to higher 1991) until, probably, as recently as Late climate aridity, it probably increased up to Khvalynian (Badyukova, 2005). 15–30 ppt or even higher (Aladin, 1989; Most authors (e.g. Băcescu, 1940; Aladin & Plotnikov, 2000). Babadzhan Lake Bănărescu, 1991; Dumont, 2000) have con- existed for about 1 million years (Aladin & cluded that the primary Miocene basins, Plotnikov, 2000) or less (Popov et al., 2004) the Sarmatian and Pontian Lakes, played and undergone a drastic further regression. a decisive role in initializing the radiation This basin, Balakhanian, which occupied of most Ponto-Caspian lineages and terms the South Caspian depression and the Kura such as “Sarmatian relicts” or “Pontian rel- Gulf, also known as the Reservoir of the Pro- icts” are common in the literature when re- ductive Series, played a key role in the his- ferring to the origins of the local fauna. It is tory of the Caspian biota (reviewed by e.g. generally believed that taxa of Miocene ori- Tarasov, 2001). Most authors suppose that gin survived in the succeeding Pliocene and this basin was saline or hypersaline (about Pleistocene basins of the Black and Caspian 100 ppt or higher) and traditionally, since Seas. However, because both basins experi- Mordukhai-Boltovskoi (1960), it has been enced at least one major bout of extinction accepted that the Caspian Pontian biota ex- during episodes of high salinity, coupled perienced a bout of extinctions. However, a with several opportunities for subsequent group of well-known experts on the palaeo- faunal exchange, there is much confusion history of Paratethys (Popov et al., 2004) regarding the evolutionary history of the supposes that the Balakhanian basin was fauna (Cristescu et al., 2003). freshwater. With regard to fishes, a key question The drastic regression during the Ba- is thus the salinity tolerance and salinity lakhnian was followed by a major (the larg- preferences of different groups of taxa in

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 300 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA terms of both the extant adaptations and MATERIAL AND METHOD the evolution of ecological characteris- tics through time. With regard to salinity, The initial database comprised over four ecological groups are distinguished 2800 taxa (family to subspecies or local among the Caspian Sea animals: 1. freshwa- “form” of doubtful status) of lampreys and ter forms, inhabiting estuaries and coastal freshwater fishes inhabiting over 200 drain- waters with a salinity of 0–2 ppt; 2. coastal ages and lake basins entirely or partially ly- and brackish forms, occurring in waters of ing within the borders of the former USSR a salinity ranging from around 2 to 7 ppt and adjacent countries (see in Naseka & (some species may be euryhaline living in Bogutskaya, 2007). a broader range of the salinity); 3. brackish For the purposes of this study, geographic distribution of some 350 taxa from water forms inhabiting waters of a salinity the Caspian and Black Sea basins were ana- from 3–5 to 10–11 ppt; 4. ‘marine’ forms lyzed. The principal sources for these data (mostly of Mediterranean origin) found are material deposited at the Zoological in waters of a salinity 8–10 ppt and higher Institute of the Russian Academy of Sci- (Aladin & Plotnikov, 2000). ences (St. Petersburg), in Kalmyk State Traditionally (since Mordukhai-Bol- University (Elista), Caucasian Biosphere tovskoi, 1960, 1964, 1979; Zenkevich, Reserve (Adler), Natural History Museum 1963), the fish species of the Caspian Sea (Vienna), Zoological Institute and Museum are grouped as autochthonous, freshwater, of Hamburg University, Canadian Museum Mediterranean, and Arctic. This grouping is of Nature (Ottawa) collections, field obser- based on a mixture of different criteria, eco- vations of a number of expeditions to the logical and historical ones, and gives only drainage areas of the Kuban and Western a very preliminary picture of the fish fauna Transcaucasia (2001, 2002), to the Lower origin and evolution in the Caspian basin. Don and Lower Volga (2002), Northern Besides, our knowledge on the taxonomy Azov region and the Crimea (2002, 2003), and phylogeny of many groups dramatically Daghestan (2004), Azerbaijan (2008), and changed since 1960–80s. critically analyzed data from extensive ex- Understanding of endemic radiations, isting literature. Some groups have not phylogenies and migration of the fauna been revised yet taxonomically or phyloge- are among the best tools in the reconstruc- netically. As a result, the taxonomic assign- tion of past paleogeographic changes, and ments given to some fishes are based on pre- vise versa, understanding successive stages liminary although reasonable assumptions. in the evolution and fragmentation of the Fish taxa are classified according to their Paratethys basin provide the opportunity to tolerance to salt water and mode of life ac- gain new insights into the biotic diversity in cording to Kessler (1877) and Myers (1938, general and the phylogeny of different taxa 1949, 1951). and communities in particular. Thus, the goal of this paper is to review the Caspian Sea fish fauna composition and RESULTS AND DISCUSSION zoogeography using the most recent taxo- General characteristic of the fish fauna nomic and phylogenetic data, both origi- nal and taken from literature. Ecological Indigenous fish fauna of the Caspian groups of species are discussed. Compari- Sea basin (including drainages of rivers be- sons between Northern, Middle and South longing to it) encompass 159 species and Caspian fish faunas are done as well as a subspecies from 60–62 genera (four to six comparison with some fish taxa distributed endemic) of 19 families. Ninety-nine species in the Black Sea. and subspecies (62%) may be considered

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA 301 endemic to the basin. The most numerous Lotidae: Lota Oken, 1817. is the family Cyprinidae (27 genera), then Atherinidae: Atherina Linnaeus, 1758. goes Gobiidae (12 genera); other families Gasterosteidae: Pungitius Coste, 1848. are much less numerous (1–3 genera). Syngnathidae: Syngnathus Linnaeus, 1758. Cottidae: Cottus Linnaeus, 1758. List of families and genera Percidae: Gymnocephalus Bloch, 1793, of the Caspian Sea basin fishes Perca Linnaeus, 1758, Sander Oken, 1817. Gobiidae: Anatirostrum Iljin, 1930 (en- Petromyzontidae: Caspiomyzon Berg, demic), Babka Iljin, 1927 (earlier consid- 1906 (endemic), Eudontomyzon Regan, ered a synonym or a subspecies of Neogo- 1911, Lampetra Bonnaterre, 1788. bius), Benthophiloides Beling & Iljin, 1927 Acipenseridae: Acipenser Linnaeus, (including Asra Iljin, 1941, endemic of 1758, Huso Brandt & Ratzeburg, 1833 the Caspian Sea which may be a distinct Clupeidae: Alosa Linck, 1790, Clupeo- genus), Benthophilus Eichwald, 1831, Ca- nella Kessler, 1877. spiosoma Iljin, 1927, Chasar Vasilieva, Cyprinidae: Rhodeus Agassiz, 1832, Bar- 1996 (endemic of the Caspian Sea but may bus Cuvier, 1816, Capoeta Valenciennes, be a synonym of Ponticola), Hyrсanogobius 1842, Luciobarbus Heckel, 1843, Carassius Iljin, 1928 (endemic; a synonym of Knipo- Jarocki, 1822, Cyprinus Linnaeus, 1758, Go- witschia by some authors), Knipowitschia bio Cuvier, 1816, Romanogobio Bănărescu, Iljin, 1927, Mesogobius Bleeker, 1874, 1961, Abramis Cuvier, 1816, Acanthalbur- Neogobius Iljin, 1927, Ponticola Iljin, 1927 nus Berg, 1916, Alburnoides Jeitteles, 1861, (earlier considered a synonym or a subspe- Alburnus Rafinesque, 1820, Aspius Agassiz, cies of Neogobius), Proterorhinus Smitt, 1832, Ballerus Heckel, 1843, Blicca Heckel, 1899. 1843, Chondrostoma Agassiz, 1832, Leu- Indigenous fish fauna of the Caspian calburnus Berg, 1916 (endemic or not for Sea proper (the sea, lagoons and river del- may be a synonym of the genus Telestes Bo- tas) including those species which are only naparte, 1840, M. Kottelat, pers. comm.), occasionally found in the sea includes 115 Leucaspius Heckel & Kner, 1858, Leuciscus species and subspecies from 52 genera and Cuvier, 1816, Phoxinus Rafinesque, 1820, 15 families (Table). Pseudophoxinus Bleeker, 1860, Rutilus Ra- The most numerous is the family Gobii- finesque, 1820, Scardinius Bonaparte, 1837, dae (35 species from 12 genera), then goes Squalius Bonaparte, 1837, Vimba Fitzinger, Cyprinidae (32 species and subspecies from 1873, Pelecus Agassiz, 1835, Tinca Cuvier, 22 genera) and Clupeidae (22 species and 1816. subspecies from two genera). The number Cobitidae: Cobitis Linnaeus, 1758, Mis- of Caspian species and subspecies, 115, is gurnus La Cepède, 1803, Sabanejewia Vla- markedly less than that in the Black and dykov, 1929 Mediterranean seas with about 200 and Nemacheilidae: Barbatula Linck, 1790, 550 species and subspecies, respectively. Oxynoemacheilus Banarescu & Nalbant, Endemic for the sea are at least two genera, 1966, Paracobitis Bleeker, 1863. Caspiomyzon, Anatirostrum, but we sup- Siluridae: Silurus Linnaeus, 1758. pose that Hyrcanogobius and Chasar should Exocidae: Esox Linnaeus, 1758. be also considered as distinct genera until Osmeridae: Osmerus Linnaeus, 1758. a phylogenetic study is done, that lifts the Coregonidae: Coregonus Linnaeus, 1758, number of endemic genera up to four. The Stenodus Richardson, 1836. number may be five if Asra is accepted as Thymallidae: Thymallus Cuvier, 1829. a separate genus. At species level, endemic Salmonidae: Hucho Günther, 1866, Sal- are 73 species and subspecies (63.5% of the mo Linnaeus, 1758. total number).

Table. List of indigenous fish taxa known to occur in the Caspian Sea (e, endemic for the Caspian; +, present/ recorded in North and Middle+South Caspian; other abbreviations explained in text).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

PETROMYZONTIDAE + + + Caspiomyzon Berg, 1906 e + + C. wagneri (Kessler, 1870) anadr e + + ACIPENSERIDAE + + + Acipenser Linnaeus, 1758 + + + A. gueldenstaedtii Brandt & Ratzeburg, 1833 anadr + + + A. nudiventris Lovetsky, 1828 anadr + + + A. persicus Borodin, 1897 anadr e + + A. ruthenus Linnaeus, 1758 fluv + + + A. stellatus Pallas, 1771 anadr + + + Huso Brandt & Ratzeburg, 1833 + + + H. huso (Linnaeus, 1758) anadr + + + CLUPEIDAE + + + Alosa Linck, 1790 + + + A. braschnikowi braschnikowi (Borodin, 1904) marine e + + A. braschnikowi agrachanica (Mikhailovskaya, 1941) marine e + + A. braschnikowi autumnalis (Berg, 1915) marine e + A. braschnikowi grimmi (Borodin, 1904) marine e + A. braschnikowi kisselevitschi (Bulgakov, 1926) marine e + A. braschnikowi nirchi (Morozov, 1928) marine e + A. braschnikowi orientalis (Mikhailovskaya, 1941) marine e + A. braschnikowi sarensis (Mikhailovskaya, 1941) marine e + A. caspia caspia (Eichwald, 1838) marine e + + A. caspia aestuarina (Berg, 1932) marine e + A. caspia knipowitschi (Iljin, 1927) marine e + A. caspia persica (Iljin, 1927) marine e + A. caspia salina (Svetovidov, 1936) marine e + A. curensis (Suvorov, 1907) marine e + + A. kessleri (Grimm, 1887) anadr e + + A. saposchnikowii (Grimm, 1885) marine e + + A. sphaerocephala (Berg, 1913) marine e + A. volgensis (Berg, 1913) anadr e + + Clupeonella Kessler, 1877 + + + C. caspia Svetovidov, 1941 marine e + C. engrauliformis (Borodin, 1904) marine e + +

Table (continued).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

C. grimmi Kessler, 1877 marine e + C. tscharchalensis (Borodin, 1896) estuarine e + CYPRINIDAE + + + Acheilognathinae + + Rhodeus Agassiz, 1832 + + Rhodeus sp. fluv e + Barbinae + + + Barbus Cuvier, 1816 + + B. cyri De Filippi, 1865 fluv e + Capoeta Valenciennes, 1842 + + C. gracilis (Keyserling, 1861) fluv + + Luciobarbus Heckel, 1843 + + + L. brachycephalus caspius (Berg, 1914) fluv&anadr + + + L. capito capito (Gueldenstaedt, 1773) fluv&anadr + + + Cyprininae + + + Carassius Jarocki, 1822 + + C. carassius (Linnaeus, 1758) fluv + + C. gibelio (Bloch, 1782) fluv + + Cyprinus Linnaeus, 1758 + + + C. carpio Linnaeus, 1758 fluv&semi-anadr + + + Gobioninae + + Gobio Cuvier, 1816 + +

G. volgensis Vasil'eva, Mendel, Vasil'ev, Lusk & fluv e + Lusková, 2008

Romanogobio Bănărescu, 1961 + + R. albipinnatus (Lukasch, 1933) fluv e + Leuciscinae + + + Abramis Cuvier, 1816 + + + A. brama (Linnaeus, 1758) semi-anadr + + + Alburnus Rafinesque, 1820 + + + A. alburnus (Linnaeus, 1758) fluv + + A. chalcoides (Gueldenstaedt, 1772) anadr e + + A. hohenackeri Kessler, 1877 fluv + + Aspius Agassiz, 1832 + + + A. aspius (Linnaeus, 1758) semi-anadr + +

Table (continued).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

A. aspius taeniatus (Eichwald, 1831) anadr e + Ballerus Heckel, 1843 + + + B. ballerus (Linnaeus, 1758) fluv&semi-anadr + + B. sapa (Pallas, 1814) fluv + + + Blicca Heckel, 1843 + + B. bjoerkna bjoerkna (Linnaeus, 1758) fluv&semi-anadr + + B. bjoerkna transcaucasica Berg, 1916 fluv&semi-anadr e + Chondrostoma Agassiz, 1832 + + Ch. variabile Jakovlev, 1870 fluv + + Leucaspius Heckel & Kner, 1858 + + + L. delineatus (Heckel, 1843) fluv + + Leuciscus Cuvier, 1816 + + L. idus (Linnaeus, 1758) fluv&semi-anadr + + L. leuciscus (Linnaeus, 1758) fluv + + Rutilus Rafinesque, 1820 + + + R. caspicus (Yakovlev, 1870) semi-anadr e + + R. kutum (Kamensky, 1901) anadr e + + R. rutilus (Linnaeus, 1758) fluv + + Scardinius Bonaparte, 1837 + + S. erythrophthalmus (Linnaeus, 1758) fluv&semi-anadr + + Squalius Bonaparte, 1837 + + S. cephalus (Linnaeus, 1758) fluv + + S. orientalis (Nordman, 1840) fluv + + Vimba Fitzinger, 1873 + + + V. persa (Pallas, 1814) anadr e + + Pelecinae + + + Pelecus Agassiz, 1835 + + + P. cultratus (Linnaeus, 1758) fluv&semi-anadr + + + Tincinae + + Tinca Cuvier, 1816 + + T. tinca (Linnaeus, 1758) fluv + + COBITIDAE + + Cobitis Linnaeus, 1758 + + C. melanoleuca Nichols, 1925 fluv + +

Table (continued).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

Misgurnus La Cepède, 1803 + + M. fossilis (Linnaeus, 1758) fluv + + Sabanejewia Vladykov, 1929 + + S. aurata (De Filippi, 1863) fluv e + S. caspia (Eichwald, 1838) fluv e + S. caucasica (Berg, 1906) fluv e + SILURIDAE + + + Silurus Linnaeus, 1758 + + + S. glanis Linnaeus, 1758 fluv&semi-anadr + + + ESOCIDAE + + + Esox Linnaeus, 1758 + + + E. lucius Linnaeus, 1758 fluv&semi-anadr + + + COREGONIDAE + + Stenodus Richardson, 1836 + + S. leucichthys (Gueldenstaedt, 1772) anadr e + + SALMONIDAE + + + Salmo Linnaeus, 1758 + + + S. caspius Kessler, 1877 fluv&anadr e + S. ciscaucasicus Dorofeyeva, 1967 fluv&anadr e + + LOTIDAE + + Lota Oken, 1817 + + L. lota (Linnaeus, 1758) fluv + + ATHERINIDAE + + + Atherina Linnaeus, 1758 + + + A. caspia Eichwald, 1831 marine e + + GASTEROSTEIDAE + + + Pungitius Coste, 1848 + + + P. platygaster (Kessler, 1859) fluv&estuarine + + + SYNGNATHIDAE + + + Syngnathus Linnaeus, 1758 + + + S. caspius Eichwald, 1838 marine e + + PERCIDAE Cuvier, 1816 + + + Perca Linnaeus, 1758 + + P. fluviatilis Linnaeus, 1758 fluv + +

Table (continued).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

Sander Oken, 1817 + + + S. lucioperca (Linnaeus, 1758) fluv&semi-anadr + + + S. marinus (Cuvier, 1828) marine + + S. volgensis (Gmelin, 1788) fluv&semi-anadr + + GOBIIDAE + + + Anatirostrum Iljin, 1930 e + A. profundorum (Berg, 1927) marine e + Babka Iljin, 1927 + + + B. macrophthalma (Kessler, 1877) marine e + + Benthophiloides Beling & Iljin, 1927 + + B. brauneri Beling & Iljin, 1927 marine&estuarine + + B. turcomanus (Iljin, 1941) marine e + Benthophilus Eichwald, 1831 + + + B. abdurahmanovi Ragimov, 1978 marine&estuarine e + + B. baeri Kessler, 1877 marine e + + B. casachicus Ragimov, 1978 marine e + B. ctenolepidus Kessler, 1877 marine e + B. granulosus Kessler, 1877 marine&estuarine e + + B. grimmi Kessler, 1877 marine e + B. kessleri Berg, 1927 marine e + + B. leobergius Berg, 1949 marine e + + B. leptocephalus Kessler, 1877 marine e + B. leptorhynchus Kessler, 1877 marine e + B. macrocephalus (Pallas, 1787) marine&estuarine e + + B. mahmudbejovi Ragimov, 1976 marine&estuarine e + + B. pinchuki Ragimov, 1982 marine e + B. ragimovi Boldyrev & Bogutskaya, 2004 marine e + B. spinosus Kessler, 1877 marine e + B. svetovidovi Pinchuk & Ragimov, 1979 marine e + Caspiosoma Iljin, 1927 + + C. caspium (Kessler, 1877) marine&estuarine + + Hyrcanogobius Iljin, 1928 e + + H. bergi Iljin, 1928 marine&estuarine e + + Knipowitschia Iljin, 1927 + + + K. caucasica (Berg, 1916) marine&estuarine + +

Table (continued).

Whole Middle Ecological North Taxon Caspian and South group Caspian Sea Caspian

K. iljini Berg, 1931 marine e + K. longecaudata (Kessler, 1877) marine&estuarine + + + Mesogobius Bleeker, 1874 + + + M. nigronotatus (Kessler, 1877) marine e + M. nonultimus (Iljin, 1936) marine e + + Chasar Vasilieva, 1996 e ? + Ch. bathybius (Kessler, 1877) marine e ? + Neogobius Iljin, 1927 + + + N. caspius (Eichwald, 1831) marine e + ?

marine&estuarine N. pallasi (Pallas, 1814) e+ + &fluv

marine&estuarine N. melanostomus affinis (Eichwald, 1831) e+ + &fluv Ponticola Iljin, 1927 + + + P. goebelii (Kessler, 1874) marine e ? +

marine&estuarine P. gorlap (Iljin, 1949) e+ + &fluv

P. syrman eurystomus (Kessler, 1877) marine&estuarine e + + Proterorhinus Smitt, 1899 + + + Proterorhinus sp. (Lower Volga tube-nose goby) fluv&estuarine e + P. nasalis (De Filippi, 1863) marine e + +

Reported in the Caspian Sea are about minck & Schlegel, 1846), Aristichthys nobi- 28 non-indigenous species from 18 genera lis (Richardson, 1845), Hypophthalmichthys of 14 families, as given below. molitrix (Valenciennes, 1844). Acipenseridae: Acipenser baerii baicalen- Salmonidae: Oncorhynchus gorbuscha sis Nikolsky, 1896, Acipenser baerii chatys (Walbaum, 1792), Oncorhynchus keta (Wal- Drjagin, 1948. baum, 1792), Oncorhynchus kisutch (Wal- Polyodontidae: Polyodon spathula (Wal- baum, 1792), Oncorhynchus (Rhabdofario) baum, 1792). mykiss (Walbaum, 1792), Salmo salar Lin- Anguillidae: Anguilla anguilla (Lin- naeus, 1758. naeus, 1758). Mugilidae: Liza aurata (Risso, 1810), Engraulidae: Engraulis encrasicolus (Lin- Liza haematocheilus (Temminck & Schlegel, naeus, 1758). 1845), Liza saliens (Risso, 1810). Cyprinidae: Ctenopharyngodon idella Poeciliidae: Gambusia affinis (Baird et Gi- (Valenciennes, 1844), Hemiculter leucisculus rard, 1853), Gambusia holbrooki Girard, 1859. (Basilewsky, 1855), Carassius auratus (Lin- Gasterosteidae: Gasterosteus aculeatus naeus, 1758), Pseudorasbora parva (Tem- Linnaeus, 1758.

Moronidae: Morone saxatilis (Wal- carassius, Carassius gibelio, Gobio volgensis, baum, 1792). Romanogobio albipinnatus, Ballerus sapa, Mullidae: Mullus barbatus Linnaeus, Alburnus alburnus, Alburnus hohenackeri, 1758. Chondrostoma variabile, Leucaspius delinea- Scombridae: Scomber scombrus Lin- tus, Leuciscus leuciscus, Rutilus rutilus ruti- naeus, 1758. lus, Squalius cephalus, Squalius orientalis, Channidae: Channa argus (Cantor, 1842). Tinca tinca, Cobitis melanoleuca, Misgurnus Scophthalmidae: Psetta maeotica fossilis, Sabanejewia aurata, Sabanejewia (Pallas, 1814). caspia, Sabanejewia caucasica, Lota lota, Pleuronectidae: Platichthys flesus (Lin- Perca fluviatilis. When these species are ex- naeus, 1758). cluded, the number of species inhabiting the Only few species have been established, sea falls to 90. Among them, 17 occur only such as Pseudorasbora parva, Hemiculter in the North Caspian and 25 (may be 27) – leucisculus, Liza aurata, Liza saliens, Gam- only in the Middle and South Caspian. busia (probably two species), Gasterosteus Forty-eight species (including three species aculeatus. Some species are questionably with questionable distribution) inhabit or established but numerous in the basin due migrate through all three major partitions to stocking, such as Aristichthys nobilis, of the sea. Hypophthalmichthys molitrix, Ctenophar- yngodon idella. The Indian carps (Cyprini- Ecological groups of fishes dae) Cirrhinus mrigala, Labeo rohita and Catla catla are being reared in aquaculture Classification introduced by Kessler stations and are potential escapees into the (1877) is base on criteria of physical habi- natural environment (Gilkolaei, 2007, cited tats and the presence/absence of migrations from Coad, 2008). between them; he grouped the Aral-Ponto- Non-indigenous species are not included Caspian fishes into marine, fluvial, ‘of vari- in the zoogeographical discussion below. ous waters‘ [“raznovodnyye”], anadromous and semi-anadromous. This classification Distribution of species and subspecies concerns tolerance to salt water by indi- in North, Middle and South Caspian rection only. It worth emphasizing that dealing with the Aral-Caspian fishes any Analyzing distribution of fishes, we author realized well that no one species is found no significant difference between true marine for salinity in these water bod- the Middle Caspian and the South Caspian ies hardly exceeds 13.7 ppt in most areas. A (Naseka & Bogutskaya, 2007). term marine reflects the geomorphology of As it can be seen from the Table, 80 spe- the water body rather then its salinity. We cies and subspecies permanently occur or slightly modified the classification adding occasionally recorded from the North Cas- a category ‘estuarine’ and combinations of pian while 33–35 species and subspecies the categories (see Table). being only distributed in the Middle and Most of the 25 fluvial freshwater species South Caspian. Forty-four species are com- mentioned above belong to the families Cy- mon for the two ecoregions. prinidae and Cobitidae which are primary A more prominent picture can be drawn division families sensu Myers (1938, 1951) when the fluvial species, which are rarely (i.e. those families whose members are met in the sea occurring only in deltas and strictly intolerant of salt water, both cur- freshened coastal shallows, are excluded rently and historically). Lotidae and Perci- from calculations. Freshwater and fluvial dae are secondary division families (i.e. those are 25 species – Acipenser ruthenus, Rhodeus families which are supposed to be of marine sp., Barbus cyri, Capoeta gracilis, Carassius origin but contain members that now live in

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA 309 fresh water). Acipenser ruthenus may be also ers and/or open marine habitats. Most spe- classified as ‘fluv/semi-anadr’ for it histori- cies – 14 – belong to the family Gobiidae. cally had a semi-anadromous form. Eleven This group contains those species which species currently have semi-anadromous can be classified as vicarious sensu Meyers, forms, most of them belong to primary di- i. e. strictly or preferably freshwater or oli- vision families (Cyprinidae, Siluridae, Eso- gohaline species of primarily marine fami- cidae) while two – to a secondary division lies. Eleven species (69%) from this group family Percidae. Distribution of the fluvial are endemic for the Caspian Sea. species reflects zoogeographical delineation Strictly ‘marine” or almost marine (most- between river drainages rather than zooge- ly inhabiting the open sea, benthic or pelagic ography of the sea. waters) form a largest group of species from Semi-anadromous fishes (14 species the secondary division families Clupeidae and subspecies) keep spawning in fresh wa- (19 species and subspecies), Atherinidae ter (limnetic waters, 0.5 ppt and less) but (1 species), Syngnathidae (1 species), Per- forage in oligohaline water (around 0.5–5 cidae (1 species) and Gobiidae (22 spe- ppt). There is only one endemic (question- cies). All species but one (43 from 44) are able) subspecies, A. aspius taeniatus, that is endemic for the basin. Many species of this restricted by the Middle and South Caspi- group are tolerant for the whole range of an; all other taxa inhabit the North Caspian Caspian salinity though some clearly pre- or the whole sea being distributed in areas fers the upper part of the range, up to 13.7 adjacent to large river mouths, especially ppt in South Caspian, and historically could the Volga River delta. even occur and spawn in areas with higher Seventeen species and subspecies are an- salinity such as the former Mertvyy Kultuk adromous; they spawn in rivers, often much [= Zaliv Tsesarevicha, Zaliv Komsomolets] farther upstream than semi-anadromous and Kaydak bays. For example, Alosa caspia fishes, and forage all over the sea under- salina was known to spawn in the Mertvyy taking long-distance migrations. However, Kultuk Bay at a salinity of up to 32.2 ppt Caspian fishes of this group are not strictly and its larvae were found in areas with sa- diadromous sensu Myers because they mi- linity up to 45.6 ppt, and Alosa braschnikowi grate between fresh and oligohaline-me- was reported in the Kaydak Bay at a salin- sohaline waters rather then between fresh ity of 47.7 ppt (Svetovidov, 1952). and true sea (euhaline) water. They belong The data presented above clearly con- to the primary division families Cyprinidae firm and even emphasize a well known fact and Coregonidae, and to Petromyzontidae, that some Clupeidae and Gobiidae repre- Acipenseridae and Salmonidae; origin of sent in the Caspian Sea examples of adap- the latter three families are still debated in tive diversification. However, taxonomy literature (for Acipenseridae see discussion and phylogeny of the Caspian taxa can not in Artyukhin, 2008). Degree of endemism is be understood without a comparison with high in this group, 11 from 17 (64%). Most the Black Sea ‘paired’ taxa. Each of these anadromous species, especially those from groups – Alosa, Clupeonella, benthophilin the family Cyprinidae and Salmonidae, are and neogobiin gobies within the Paratethys (historically were) much more numerous in limits – meets the definition of species flocks the Middle and South Caspian being rare or sensu Greenwood (1984) – a geographically occasional migrants in the North Caspian circumscribed, monophyletic taxon charac- (entering the Volga). terized by marked radiation. This was spe- Sixteen species are classified as ‘estua- cifically underlined for the Benthophilinae rine’ mostly inhabiting deltaic areas and by Neilson & Stepien (2009). Below we try adjacent coastal shallows, some of them be- to briefly analyse the most recent data on ing distributed also in lower reaches of riv- taxonomy and phylogeny of some taxa in

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 310 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA the Caspian and the Black Sea to show their these species as distinct evolutionary sig- relationships and the supposed degree of dif- nificant units (ESUs). ferences in order to roughly estimate the de- Clupeidae. Since long time most sub- gree (and relative age) of their divergence. species and ‘forms’ of Alosa had been considered as belonging to three species – A. Comparison of the Caspian and the Black caspia (puzanok-shads), A. braschnikowi Sea fish faunas and their evolution (marine shads) and A. kessleri (anadromous shads) – distributed in both the Caspian Petromyzontidae. Caspiomyzon is the and the Black Sea basins. Then, the Black only one absolutely undoubted Caspian Sea ‘subspecies’ were considered as distinct endemic genera. There are no indications species (see reviews by Bogutskaya & Nase- that any close form existed in the Black Sea ka, 2004 and Kottelat & Freyhof, 2007) – basin though the migratory lamprey from A. immaculata Bennett, 1835 (as A. kessleri the Black Sea is still a poorly known issue pontica in Svetovidov, 1952), A. maeotica (for discussion see Kottelat et al., 2005 and (Grimm, 1901) (as A. brashnikovi maeotica Naseka & Diripasko, 2008). in Svetovidov, 1952), A. tanaica (Grimm, Acipenseridae. Most authors do not ac- 1901) (as A. caspia tanaica in Svetovidov, cept an idea that there are distinct Caspian 1952) with subspecies Alosa tanaica etemi and Black Sea species and subspecies within Battalgil, 1941, Alosa tanaica nordmanni each ‘sturgeon’ inhabiting the two basins Antipa, 1904, and Alosa tanaica palaeostomi (e.g. Artyukhin, 2008). However, at least for (Sadowsky, 1934) of disputed status. Re- few cases, there are different opinions. For spective paired species of all three groups example, Kottelat & Freyhof (2007) accept- of shads – puzanok-shads, marine shads and ed the opinion that Acipenser persicus and anadromous, or migratory, shads – in the A. colchicus Marti, 1940 are distinct species Caspian Sea are much more diverse, and though commonly considered synonyms or each contains (Table) distinct species and subspecies of the same species. Russian stur- subspecies of the uncertain status. Unfor- geon A. gueldenstaedtii from the Caspian tunately, no recent revision or phylogenetic may be different at least on the subspecies study has been done on this group of Cas- level from A. gueldenstaedtii tanaicus Marti, pian fishes but morphological differences 1940 (Sea of Azov) and A. gueldenstaedtii between them described in a number of danubicus (described as A. gueldenstaedtii detailed publications (as can be seen from colchicus nation danubica Movchan, 1967) a review by Svetovidov, 1952) deserve spe- (western Black Sea basin) (taxonomy of cial attention (Panin et al., 2005) and give Russian sturgeon was reviewed by Podush- reason to suspect that most of them are dis- ka, 2003). Huso huso from the Caspian Sea tinct species if phylogenetic methodology is was described as a distinct subspecies based applied. on morphological differences as Huso huso There are three species of Clupeonella caspicus Babushkin, 1942. Morphological in the Caspian Sea – C. engrauliformes, difference between Caspian and Black Sea С. grimmi, С. caspia – and one more spe- beluga sturgeons were earlier described cies, C. tscharchalensis, which was origi- by other authors (Sal’nikov & Malyats- nally described from the Charkhal Lake and kiy, 1934). Movchan (1970) described a then reported from backwaters at Saratov Black Sea subspecies of stellate sturgeon, (Borodin, 1905). Both C. caspia and C. A. stellatus ponticus Movchan, 1970. These tscharchalensis were earlier considered syn- taxonomic conclusions have been largely onyms of C. cultriventris (Nordmann, 1840). ignored by most other authors but need Besides the latter species, there are two special attention at least for understanding more local freshwater species in the Black of Caspian and Black Sea lineages within Sea basin – C. abrau Malyatskiy, 1928

(Abrau Lake, Russia) and C. muhlisi Neu, gether with some clear morphological differ- 1934 (Apolyond Lake, Turkey). Clupeonella ences give good reasons for considering R. engrauliformes and С. grimmi, being typi- kutum and R. frisii as distinct species. Simi- cal brackish water marine pelagic tyulkas lar data were received for Vimba (Hänfling which commonly occurs over big depths in et al., 2009) supporting (not contradicting) the Middle and South Caspian. the suggestion to rank the Caspian vimba as Cyprinidae. Among anadromous cy- a separate species V. persa. prinids the most striking difference of the Salmonidae. Taxonomic status of many Caspian fauna from the Black Sea fauna is subspecies, ‘forms’ and local groups popula- the presence in the Caspian (and the Aral tions of Salmo trutta Linnaeus, 1758 in wide Sea basin) of two species of the genus Lu- sense has been one of the most controver- ciobarbus. This genus contains over 30 spe- sial issues in ichthyology since long time. cies widely distributed in the Iberian Pen- Some authors supposed that S. caspius Kes- insula, North Africa and Middle East but sler, 1877 (South Caspian, Kura and Ira- absent from the Black Sea. Three other ana- nian rivers), S. ciscaucasicus Dorofeyeva, dromous cyprinid species form pairs with 1967 (eastern Middle and North Caspian, the Black Sea – Rutilus kutum and R. frisii rivers from northern Azerbaijan to Volga (Nordmann, 1840), Vimba persa and V. vim- and Ural, mostly Terek River) and Salmo ba (Linnaeus, 1758), A. chalcoides (prob- labrax Pallas, 1814 from the Black Sea may ably conspecific with A. chalcoides aralen- represent distinct species (Bogutskaya & sis Berg, 1924) and a number of migratory Naseka, 2004; Bogutskaya & Dorofeyeva, shemayas in different river drainages and 2007; Kottelat & Freyhof, 2007). We do not lake basins of the Black Sea (A. danubicus know any publication analysing the time of Antipa, 1909, A. derjugini Berg, 1923, A. is- divergence between the three species. The tanbulensis Battalgil, 1941, A. leobergi Frey- age of S. caspius and S. ciscaucasicus diver- hof & Kottelat, 2007, A. mandrensis (Dren- gence can be dated as post-Balakhanian; S. sky, 1943), A. mentoides Kessler, 1859, A. caspius appears to be closer to an ancestor sarmaticus Freyhof & Kottelat, 2007, A. of the both species which was distributed in schischkovi (Drensky, 1943), A. vistonicus the restricted Balakhanian basin (current Freyhof & Kottelat, 2007; for more infor- South Caspian) while S. ciscaucasicus may mation on these species see Freyhof & Kot- represent a lineage that expanded north- telat, 2007a, 2007b and Kottelat & Freyhof, wards during the Akchagilian transgression, 2007). The Alburnus complex has not been and gene flow between the lineages became yet phylogenetically studied while the for- interrupted because of stable using of differ- mer two pairs of species (formerly pairs of ent rivers for spawning. conspecific subspecies) have been analysed Atherinidae and Syngnathidae. Zen- using molecular markers. It was shown for kevich (1963) supposed that two ‘marine’ R. kutum and R. frisii (though the taxonom- species (names given as Atherina mochon ic conclusion was not done) that the latest pontica and Syngnathus nigrolineatus) had gene migration between them from the Cas- the Mediterranean-Atlantic origin and pen- pian Sea to the Black Sea occurred on aver- etrated the Caspian basin from the Black age 250,000–450,000 years ago and migra- Sea relatively recently, during Khvalynian tion in the opposite direction took place on some 50,000 years ago. However, Tara- average 270,000–480,000 years ago (Kotlik sov (2001) has a different opinion which et al., 2008). The authors made a conclusion is based on published data on differences that the two ‘forms’ maintained refugial in morphology, ecology and parasitic fauna populations in both the Black Sea and the of the Caspian and the Black Sea Atherina, Caspian Sea and diverged despite periods Syngnathus and Knipowitschia species; this of migration between them. These data to- author estimates the age of divergence as

5.5–6.0 Mya and supposes that holoeuryha- coastal waters (B. kessleri) with water saline ancestors of the Caspian species inhab- linity of 10–14 ppt while a single species ited the Pontic basin (N1p) and survived only, B. granulosus, is widely spread in both the Balakhanian salinity crisis. We agree fresh and brackish waters (up to more than with this opinion and consider Atherina 20‰) of coastal waters of almost the whole boyeri Risso, 1810 and A. caspia as distinct sea, but prefers highly freshened waters of species as well as Syngnathus abaster Risso, river deltas and lower reaches. The second 1827 and S. caspius. group is the only one distributed now out Gobiidae. The genus Benthophilus now of the Caspian Sea and adopted to highly includes 20 species, 16 from which occur on- freshened or pure fresh waters. Three Cas- ly in the Caspian basin (Boldyrev & Boguts- pian species display undoubted phenotypic kaya, 2004, 2006). Based on morphological affinity to the species from the Pontic ba- characters and distribution the species can sin – B. mahmudbejovi and B. durrelli, B. be divided into four groups. First group in- аbdurahmanovi and B. magistri, B. leober- cludes five species: B. leptorhynchus, B. grim- gius and B. stellatus. Benthophilus nudus mi, B. svetovidovi, B. kessleri, and B. granulo- from the Black Sea is also close to the latter sus. Second group is the largest and contains pair. Similar to the first group, species of the nine species: B. mahmudbejovi, B. durrelli third and fourth groups include species dis- Boldyrev & Bogutskaya, 2004, B. abdurah- tributed only in the Caspian Sea and clearly manovi, B. magistri, B. leobergius, B. stella- confined to deeper waters (30–300 m) of tus (Sauvage, 1874), B. nudus Iljin, 1927, the Middle and South Caspian. B. macrocephalus, and B. casachicus. Third These data give reasons to propose group contains four species: B. сtenolepidus, two opposing models, the origin of species B. leptocephalus, B. ragimovi, and B. pinchu- via late Miocene vicariance events for the ki. Fourth group includes only two species: Black Sea/Caspian lineages vs. late Plio- B. spinosus and B. baeri. Some assumptions cene through Holocene dispersal events for can be done based upon the most evident lineages of the Black Sea basin. Both hy- polarities of some morphological structures. potheses suggest that the extant high diver- Thus, the most ancestral type of dermal os- sity of endemic Caspian Benthophius species sification is apparently that one with no dif- reflects the continuity of the fauna since ferentiation into different types of ossicles late Miocene-Pliocene and a complex pro- when all of them resemble modified ctenoid cess of speciation to specific conditions of scales being embedded into skin with only the “brackish water sea”. They are different posterior edge exposed outside. Specializa- in explaining the historical reasons of the tion included differentiation into tubercles fewness of Benthophilus in the Black Sea ba- and granules with subsequent reduction of sin. The vicariance model suggests that the both tubercles and granules or enlargement Pontic fauna of Benthophilus experienced of tubercles and decrease of the number of a high rate of extinctions due to Pleisto- granules. If this hypothesis is true, so the cene climatic and hydrologic changes that first group is the most ancestral one and the produced dramatic transformations in the second one diverged from it; the third and Black Sea basin. The few survivors retreat- the fourth groups are probable derivates of ed into the estuarine, lacustrine or riverine the second group. habitats along the margins of the Black Sea Species of the presumably ancestral where they are represented now by 4–5 spe- group occur only in the Caspian Sea, with cies. The dispersal model suggests relatively four species having comparatively lim- recent colonization events during periods ited geographical distribution in Middle of major transgression when brief contacts Caspian at depths up to 200 m (B. lepto- between the Caspian and the Black seas al- rhynchus, B. svetovidovi, B. grimmi) or in lowed faunal exchange, for example, in the

© 2009 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 18(2): 295–317 A.M. NASEKA & N.G. BOGUTSKAYA. FISHES OF CASPIAN SEA 313 late Pliocene (between Akchagylian and nean fauna with the isolation of the Parat- Kuyalnikian basins), during the Apshero- ethys during the late Miocene and only the nian transgression of the Pleistocene, or partial flooding of the Mediterranean from throughout the Pleistocene. Both hypoth- the Paratethys in the early Pliocene allowed eses suggest that the ancestor of Benthophi- Sarmatian gobies to spread westwards. lus inhabited Pontian basin about 7.1–5.8 Within the Ponto-Caspian basin, evolution Mya with some other “Pontic relicts” and of species flocks was favoured by basin sub- survived the Balakhanian regression. Niel- divisions and rejoinings. The benthophilines son & Stepien (2009) provide the estimated may be a monophyletic group from these age for the node of tribe Neogobiini (Neogo- events. Their data made it possible to cal- bius) + tribe Benthophilini (Benthophilus + culate approximate divergence times among Caspiosoma) as 9.18 Mya. lineages of Benthophilinae. The initial sepa- Quite recently, Neilson & Stepien (2009) ration of the Black and Caspian Sea basins provided the first comprehensive phyloge- 5 Mya coincides with the diversification netic and biogeographic analysis of ‘neogo- of most Neogobiini + Ponticolini genera biins’ and ‘benthophilins’ (tadpole gobies) (Neogobius, Babka, Mesogobius, Ponticola, based on sequences from two mitochondrial and Proterorhinus), as well as diversification and two nuclear genes with maximum parsi- within Benthophilini (separation of Bentho- mony, likelihood, and Bayesian approaches. philus and Caspiosoma. In addition to older Their data provided a solid basis for recog- divergences within Ponto-Caspian taxa, nizing the subfamily Benthophilinae, which several recent separation events are identi- encompasses both the ‘neogobiins’ and tad- fied such as several radiation events which pole gobies, and genetically diverges from occurred 1–2 Mya among the Ponticolini other Gobiidae subfamilies including (non- during the midst of the Pleistocene glacial monophyletic) Gobiinae and Gobinelli- cycles or Pleistocene-aged divergences of nae. Benthophilinae contains three tribes: the two subspecies of Neogobius melanosto- Neogobiini (Neogobius), Ponticolini (con- mus (N. m. melanostomus in the Black Sea taining the genera Mesogobius, Proterorhi- and N. m. affinis in the Caspian Sea). nus, Babka, and Ponticola elevating the latter two from subgenera and removing them CONCLUSIONS from the formerly paraphyletic Neogobius), and Benthophilini. Within Ponticolini, Pro- Though the lack of Ponto-Caspian in- terorhinus and Mesogobius comprise the sis- vertebrate species from Pliocene deposits in ter clade of the Ponticola and Babka clade. the bottom sediments of the Caspian Sea has Neilson & Stepien (2009) further dis- sometimes been interpreted as evidence for a cussed the evolutionary scenario of gobiids. mass extinction, implying a discontinuity of They suppose that the Black and Caspian the fauna in the Caspian Sea and a subsequent Sea basins contain an endemic Sarmatian repopulation by lineages from the Black Sea, fauna of gobies. There are two main clades, the presented data provide good reasons for the gobiine-benthophilines (or transverse a conclusion that the role of freshwater or gobiids) and the pomatoschistines (or sand slightly brackish coastal habitats as refugia gobies), that have probably been distinct along the basin margins during regressions of for at least 40 million years. The transverse the sea was very important. This appears to gobiids include Mesogobius, Neogobius, Pro- be true even for the Balakhanian crisis. The terorhinus, Chasar, Anatirostrum, Bentho- conclusion supports hypotheses of other au- philoides, Benthophilus and Caspiosoma thors on a significant role of freshened coast- while the sand gobies include Knipowitschia al refugia in allowing lineage survival during and Hyrcanogobius. The Sarmatian fauna intermittent pulses of high salinity (Tarasov, was separated from the Atlantic-Mediterra- 2001; Cristescu et al., 2003).

The different divergence times discussed Artyukhin, E.N. 2008. Osetrovyye (ekologiya, for some groups above (late Miocene, Plio- geograficheskoye rasprostraneniye i filogeni- cene and Pleistocene) support a scenario ya) [Acipernseridae (ecology, geographical of repeated colonization and vicariance distriburtion and phylogeny]. St. Petersburg events in all group of fishe throughout the State University, St. Petersburg. 137 p. (In Russian). history of the Ponto-Caspian basin. One Băcescu, M. 1940. Les Mysidaces des eaux rou- should also suppose to find different phylo- maines (études taxonomique, morphologi- geographical patterns in lineages with con- que, bio-géographique et biologique. Anna- trasting life history strategies. It is there- les Scientifiques de l’Université de Jassy, 26, fore probable that most of the taxa, which 454–803. currently inhabit the both basins, represent Badyukova, E.N. 2005. One from arguments pairs of evolutionary significant units, sub- for the conection between the Caspian and species (probable distinct species) and spe- the Black Sea in Late Khvalynian. Geomor- cies evolved under prolonged geographical phologiya, 2: 23–47. (In Russian). isolation and exposed to different selective Bănărescu, P. 1991. Zoogeography of fresh waters, 2. Distribution and dispersal of freshwa- forces which has provoked their morpho- ter animals in North America and Eurasia. logical and physiological differentiation. AULA-Verlag, Wiesbaden: 524–1091. Besides, there are examples of intra-basin Benson, R.H. (Ed.), 1976. Biodynamic Effects isolations and divergences including di- of the Messinian salinity crisis. Palaeogeo- vergence in salinity preferences. Although graphy, Palaeoclimatology, Palaeoecology, 20 : there is a widespread opinion that Ponto- 1–170. Caspian endemics are very euryhaline, Bogutskaya, N.G. & Dorofeyeva, E.A. 2007. there is evidence that their ‘euryhalinity’ Neotype designation for Salmo spurius Pallas, is overestimated and most species groups 1814 (Teleostei: Salmonidae). Zoosystemati- (complex species sensu earlier authors) ca Rossica, 16(1): 135–137. Bogutskaya, N.G. & Naseka, A.M. 2004. Cat- consist of distinctive evolutionary lineages alogue of agnathans and fishes of fresh and (species or ESUs) demonstrating marked brackish waters of Russia with comments on regional or intraspecific variation in their nomenclature and taxonomy. KMK Publish- salinity tolerance. ers, Moscow. 389 p. (In Russian). Bogutskaya, N.G. 2007. Ecoregion Description. 452: Caspian Marine Ecoregion Description. ACKNOWLEDGEMENTS 453: Volga Delta – Northern Caspian Ecore- gion Description. [cited December 5, 2009]. The study was supported by the Biological Available from: < http://www.feow.org >. Resourses Programme (General Biology Branch, Boldyrev, V.S. & Bogutskaya, N.G. 2004. Russian Academy of Sciences) and the Biodi- Description of two new species of tadpole- versity Programme of the Presidium of Russian gobies (Teleostei: Gobiidae: Benthophilus). Acedamy of Sciences, and grants of RFBR. Zoosystematica Rossica, 13 (1): 129–135. Boldyrev, V.S. & Bogutskaya, N.G. 2006. Re- REFERENCES vision of the tadpole-gobies of the genus Benthophilus (Teleostei: Gobiidae). Ichthyo- Aladin, N.B. & Plotnikov, I.S. 2000. The Dan- logical Exploration of Freshwaters, 18: 31–96. ger of large-scale ecological catastrophy in Borodin, N.A. 1905. Relict form of the marine the Caspian (the comparative analysis of small shad in the system of the Middle Volga. causes and effects of ecological crises in the Vestnik rybopromyshlennosti, 20(5): 282–283. Aral and Caspian). The Caspian Bulletin, 4: (In Russian). 112–126. Chumakov, I.S. 1993. Radiometricheskaja shka- Aladin, N.B. 1989. The osmoregulation pecu- la dlja pozdnego kainozoja Vostochnogo Pa- liarities of the Cyprideis torosa crustacean ratetisa. Priroda, 12: 68–75. (In Russian). from the seas of the USSR. Zoologiceskiy Coad, B. 2008. Freshwater fishes of Iran. Up- Zhurnal, 68(7): 40–50. (In Russian). dated June 5, 2008 [cited December 5, 2009].

Available from: < http://www.briancoad. (Oligocene–Holocene), with particular em- com/main.asp?page=titlepage.htm .>. phasis on the Black Sea. In: Robinson, A.G. Cristescu, M.E.A., Hebert, P.D.N. & Onciu, (Ed.) Regional and petroleum geology of the T.M. 2003. Phylogeography of Ponto-Cas- Black Sea and surrounding region. American pian crustaceans: a benthic-planktonic com- Association of Petroleum Geologists, Tulsa, parison. Molecular Ecology, 12: 985–996. Oklahoma: 39–52. Dumont, H.J. 1998. The Caspian Lake: history, Katunin, D.N. 1986. Salinity of water. In: Bai- biota, structure and function. Limnology and din, S.S. & Kosarev, A.N. (Eds) Caspian Oceanography, 43: 44–52. Sea: hydrology and hydrochemistry. Nauka, Dumont, H.J. 2000. Endemism in the Ponto- Moscow: 117–128. (In Russian). Caspian fauna, with special emphasis on the Kessler, K. 1877. Ryby, vodyaschiesya i vstre- Onychopoda (Crustacea). In: Rossiter, A. & chayushchiyesya v Aralo-Kaspiysko-Ponti- Kawanabe, H. (Eds). Advances in ecological yskoy ikhtiologicheskoy oblasti [Fishes of the research. Ancient lakes: biodiversity, ecology Aralo-Caspio-Pontian region]. Trudy Aralo- and evolution. Academic Press, San Diego: Kaspiyskoy Ekspeditsii, 4: xxviii+ 360 pp., 8 181–196. pls. (In Russian). Freyhof, J. & Kottelat, M. 2007a. Review of the Kosarev A.N. & Yablonskaya E.A. 1994. The Alburnus mento species group with descrip- Caspian Sea. SPB, The Hague. 259 p. tion of two new species (Teleostei: Cyprini- Kotlik, P., Markova, S., Choleva, L., Boguts- dae). Ichthyological Exploration of Freshwa- kaya, N.G., Ekmekci, F.G. & Ivanova, P.P. ters, 18: 213–225. 2008. Divergence with gene flow between Freyhof, J. & Kottelat, M. 2007b. Alburnus vis- Ponto-Caspian refugia in an anadromous tonicus, a new species of shemaya from east- cyprinid Rutilus frisii revealed by multiple ern Greece, with remarks on Chalcalburnus gene phylogeography. Molecular Ecology, 17: chalcoides macedonicus from Lake Volvi (Te- 1076–1088. leostei: Cyprinidae). Ichthyological Explora- Kottelat, M. & Freyhof, J. 2007. Handbook of tion of Freshwaters, 18: 205–212. European Freshwater Fishes. Maurice Kotte- Golubev, G.N. 1997. Closed areas and the Case lat & J. Freyhof, Cornel & Berlin. 646 p. of the Caspian Sea Basin. In: Conference: Kottelat, M., Bogutskaya, N.G. & Freyhof, J. Perspectives of Eurasia as a Field of Global 2005. On the migratory Black Sea lamprey Communication. Publication of Japanese- German Center, Berlin, 9: 125–136. and the nomenclature of the ludoga, Peipsi Greenwood, P.H. 1984. What is a species flock? and ripus whitefishes (Agnatha: Petro- In: Echelle, A.A. & Kornfield, I. (Eds) Evo- myzontidae; Teleostei: Coregonidae). Zoo- lution of Fish Species Flocks. University of systematica Rossica, 14(1): 181–186. Maine Press, Orono: 13–19. Laskarev, V. 1924. Sur les equivalents du Sar- Hänfling, B., Dümpelmann, C., Bogutskaya, matien superieur en Serbie. In: Vujević, P. á N.G., Brandl, R. & Brändle, M. 2009. Shal- (Ed.) Receuil de traveaux offert M. Jovan low phylogeographic structuring of Vimba Cvijic par ses amis et collaborateurs. Drzhav- vimba L. across Europe suggests two distinct na Shtamparija, Beograd: 73–85. refugia during the last glaciation. Journal of Mamaev, V. 2002. Europe’s biodiversity – bio- Fish Biology, 75 (in press). geographical regions and seas. Seas around Iljina, L.B. & Nevesskaja, L.A. 1979. On pos- Europe. The Caspian Sea – enclosed and with sible connections of the Maeotian Basin with many endemic species. European Environ- the adjacent seas and on correlations of the ment Agency. 26 p. Miocene deposits of Eastern Paratethys and Mandych, A.F. (Ed.) 1995. Enclosed Seas and Tethys. Annales Geologiques des Pays Helle- Large Lakes of Eastern Europe and Middle niques, Tome Hors Serie, 3: 553–558. Asia. SPB Academic Publishing, Amster- Jones R.W. & Simmons, M.D. 1996. A review dam, The Netherlands. 273 p. of the stratigraphy of eastern Paratethys Meulenkamp, J.E., Sissingh, W. et al. 2000. (Oligocene-Miocene). Bulletin of the Natural Maps 17–23 Tertiary. In: Dercourt, J., Ga- History Museum: Geology, 52(1): 25–49. etani, M. et al. (Eds.) Atlas Peri-Tethys, Pa- Jones R.W. & Simmons, M.D. 1997. A review laeogeographical Maps. CCGM/CGMW, of the stratigraphy of Eastern Paratethys Paris: 153–268.

Mordukhai-Boltovskoi, F.D. 1960. Caspian tekhnicheskiy Bulleten’ Laboratorii Ikhtiologii fauna in Azov and Black Sea basin. Publish- INENKO RAN, 7: 19–44. (In Russian). ers of the Academy of Science, Moscow. (In Popov, S.V., Rögl, F., Rozanov, A.Yu., Steini- Russian). ger, F.F., Shcherba, I.G., & Kovac, M. Mordukhai-Boltovskoi, Ph.D. 1964. Caspian 2004. Lithological-Paleogeographic maps of fauna beyond the Caspian Sea. Internatio- Paratethys. Late Eocene to Pliocene. Courier nal Revue der Gesamten Hydrobiologie, 49: Fordchungsinstitut Senckenberg, 250, 46 pp., 139–176. 1–10 maps. Mordukhai-Boltovskoi, Ph.D. 1979. Contribu- Popov, S.V., Shcherba, I.G., Ilyina, L.B., tion and distribution of Caspian fauna in the Nevesskaya, L.A., Paramonova, N.P., light of modern data. International Revue der Khondkarian, S.O. & Magyar, I. 2006. Late Gesamten Hydrobiologie, 64: 1–38. Miocene to Pliocene palaeogeography of the Movchan, Yu.V. 1970. Morphometric character- Paratethys and its relation to the Mediter- istics of Acipenser stellatus Pall. from the Azov- ranean. Palaeogeography, Palaeoclimatology, Black-Sea basin. Vestnik Zoologii, 1970(2): Palaeoecology, 238 : 91–106. 35–41. (In Russian, English summary). Reid, D.F. & Orlova M.I. 2002. Geological and Myers, G.S. 1938. Fresh-water fishes and West evolutionary underpinnings for the success Indian zoogeography. Annual Reports of of Ponto-Caspian species invasions in the Smithsonian Institution for 1937: 339–364. Baltic Sea and North American Great Lakes. Myers, G.S. 1949. Salt-tolerance of fresh-water Canadian Journal of Fisheries and Aquatic fish groups in relation to zoogeographical Sciences, 59: 1144–1158. problems. Bijdragen tot de Dierkunde, 28: Rögl, F. 1998. Paleogeographic consideration for 315–322. the Mediterranean and Paratethys Seaways Myers, G.S. 1951. Freshwater fishes and East (Oligocene to Miocene). Annalen des Naturhi- Indian zoogeography. Stanford Ichthyologi- storisches Museums in Wien, 99A: 279–310. cal Bulletin, 4: 11–21. Rögl, F. 1999. Mediterranean and Paratethys. Naseka, A.M. & Bogutskaya, N.G. 2007. Eco- Facts and hypotheses of an Oligocene to zoogeographic ecoregions of continental wa- Miocene paleogeography (Short Overview). ter bodies of North Eurasia based on data on Geologica Carpathica, 50(4): 339–349. fish assemblages content. Sbornik Nauchnykh Sal’nikov, N.I. & Malyatskiy, S.M. 1934. Sur Trudov FGNU GosNIORKh, 337: 211–242. la systématique du grand ésturgeon (Huso (In Russian). huso L.) du bassin de la Mer Noire et de la Naseka, A.M. & Diripasko, O.A. 2008. A re- Mer d‘Asoff. Trudy Nauchnoi rybokhozyaist- cent record of a parasitic Lampetra from the vennoi biologicheskoi stantii Gruzii [Travaux Sea of Azov. Ichthyological Exploration of de la Station piscicole et biologique de Géor- Freshwaters, 19: 283–287. gie], 1(1): 31–50B. (In Russian with French Neilson, M.E. & Stepien, C.A. 2009. Escape summary). from the Ponto-Caspian: Evolution and Schulz, H.-M., Vakarcs, G. & Magyar, I. 2005. biogeography of an endemic goby species The birth of the Paratethys during the Early flock (Benthophilinae: Gobiidae: Teleostei). Oligocene: From Tethys to an ancient Black Molecular Phylogenetics and Evolution, 52: Sea analogue? Global and Planetary Change, 84–102. 49(3–4): 163–176. Nevesskaya, L.A., Goncharova, I.A., Ilyina, Semenenko, V.N. 1987. Stratigraficheskaja L.B., Paramonova, N.P., Popov, S.V., Ba- korrelatsija verkhnego miotsena i pliotsena bak, E.V., Bagdasarjan, K.G. & Voronina, Vostochnogo Paratetisa i Tetisa [Stratigraph- A.A. 1986. Istorija neogenovych mollyuskov ic correlation of Upper Miocene of Eastern Paratetisa. [History of Neogene mollusks of Paratethys and Tethys]. Naukova Dumka, Paratethys]. Nauka, Moskva. (In Russian). Kiev. 188 c. (In Russian). Panin, G.N., Mamedov, R.M. & Mitrofanov, I.V. Starobogatov Ya.I. 1970. Fauna molluskov i 2005. Sovremennoye sostoyaniye Kaspiyskogo zoogeographicheskoye raionirovaniye kon- morya [Modern state of the Caspian Sea]. tinental’nykh vodoemov ptvyjuj shara [The Nauka, Moscow. 356 p. (In Russian). mollusk fauna and zoogeographic zoning of Podushka, S.B. 2003. About the systematic continental water bodies of the Earth]. Nau- position of Azov Sea sturgeon. Nauchno- ka, Leningrad. 372 p. (In Russian).

Starobogatov, Ya.I. 1994. Systematics and pa- and geomorphology of the Caspian Region in leonthology. In: Starobogatov, Ya.I. (Ed.) the Pleistocene. Nauka, Moscow: 5–100. (In Dreissena Dreissena polymorpha (Pall) (Bi- Russian). valvia, Dreissenidae). Nauka, Moscow: 18–46. Tarasov, A.G. 2001. Hypersaline ecosystems: (In Russian). oil- and gas-sources. Edel-M Publ., Moscow. Steininger, F.F., Berggren, W.A., Kent, D.V., 111 p. (In Russian). Bernor, R.L., Sen, S. & Agusti, J. 1996. Vasiliev, I., Krijgsman, W., Langereis, C.G., Circum-Mediterranean Neogene (Miocene Panaiotu, C.E., Maţenco, L. & Bertotti, G. and Pliocene) marine-continental chrono- 2004. Towards an astrochronological frame- logic correlation of the European mammal work for the eastern Paratethys Mio–Plio- units. In: Mittmann, H.W. (Ed.) The Evolu- cene sedimentary sequences of the Focşani tion of the Western Eurasian Neogene Mam- basin (Romania). Earth and Planetary Sci- mal Faunas. Columbia University Press, New ence Letters, 227: 231–247. York. 487 p. Vasiliev, I., Krijgsman, W., Stoica, M. & Lan- Svetovidov, A.N. 1952. Sel’devye (Clupeidae). gereis, C.G. 2005. Mio-Pliocene magne- Fauna SSSR [Clupeidae, Fauna of the USSR], tostratigraphy in the southern Carpathian 2(1). Izdatel’stvo Akademii Nauk SSSR, foredeep and Mediterranean–Paratethys Moscow–Leningrad. 331 p. (In Russian). correlations. Terra Nova, 17: 376–384. Svitoch, A.A. 1991. Fluctuations of the Caspian Zenkevich, L.A. 1963. Biologiya morey SSSR Sea level in the Pleistocene (classification [Biology of seas of the USSR]. Izdatel’stvo and systematic description). In: Tcherbakov, Akademii Nauk SSSR, Moscow. 739 p. (In F.A. & Svitoch, A.A. (Eds) Palaeogeography Russian). Received 10 October 2009 / Accepted 10 December 2009.