NORTH-WESTERN JOURNAL OF ZOOLOGY 8 (1): on-first ©NwjZ, Oradea, Romania, 2012 Article No.: 121201 www.herp-or.uv.ro/nwjz 

Gammarus varsoviensis Jazdzewski, 1975 (Amphipoda, Gammaridae): a long overlooked species in Ukrainian rivers

Michał GRABOWSKI1*, Tomasz MAMOS1, Tomasz REWICZ1,

Karolina BACELA-SPYCHALSKA1 and Mykola OVCHARENKO2

1. Department of Invertebrate Zoology & Hydrobiology, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland

2. Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland *Corresponding author, M. Grabowski, E-mail: michalg@biol.uni.lodz.pl

Received: 30. August 2011 / Accepted: 13. December 2011 / Available online: 08. January 2012 / Printed: June 2012

Abstract. The first findings of Gammarus varsoviensis in Ukraine are reported based on samples collected in 2009 and 2011. Until now, the species was known predominantly from the Baltic drainage area, with only one locality in the upper Pripyat River in Belarus (Black Sea basin). Our findings extend the known geographic range of this species ca. 830 kilometers south-east, revealing its occurrence in typically lowland streams and rivers of the Dnieper system, in the forest and Pontic steppe zone of the Black Sea basin. Based on the literature data we conclude that presence of this species in Ukraine was formerly overlooked through misidentification with morphologically close Gammarus lacustris. Based on such distribution pattern we can surmise that the species is native to the Black Sea drainage area. It could possibly have migrated to the Baltic basin through the Pripyat-Bug Canal, already in the XIX century.

Key words: Dnieper River, biogeography, Pontic steppe, freshwater, gammarids, Ukraine.

Amphipods are among the most diverse crusta-cean groups inhabiting inland waters with 293 genera and nearly 1900 species known so far to oc-cur in such environment (Balian et al. 2008). Most of this diversity concentrates in the Palearctic realm, predominantly in middle latitudes, with such hotspots in Europe as Iberian, Apennine and Balkan peninsulas and also Ponto-Caspian region (Vainola et al. 2008, Hou et al. 2011). Ukraine lies almost entirely within the Black Sea drainage ba-sin, being a very important part of that region. De-spite its northern location, the area was free of ice during the Pleistocene – the Dnieper River system originated around late Miocene, ca. 13.6 million years ago (Matoshko et al. 2002), potentially offer-ing a good opportunity for long term radiation of freshwater fauna.

Surprisingly, amphipod freshwater fauna of Ukrainian inland waters has been rather poorly studied. Most research activity has focused upon large rivers such as Dniester or Dnieper and their estuaries (limans). Particularly, stress was put on the Ponto-Caspian oligohaline species (mainly of genera Pontogammarus, Obesogammarus, Dikero-gammarus and Chaetogammarus) diversified in the Black and Caspian Sea basins during subsequent transgressions and regressions and introduced during Soviet times into the contemporarily built artificial dam reservoirs (Zhuravel 1965, Pligin & Yemelyanova 1989, Grigorovich et al. 2002). Now, these studies are rather outdated. Concerning na-

tive freshwater Gammarus in Ukrainian inland wa-ters, Martynov (1931) described several new spe-cies from the Crimean Peninsula: Gammarus tauri-cus, G. nudus, G. spelaeus and G. kesslerianus. Kara-man & Pinkster (1977) listed several localities for G. kischinefensis in the Dniester River system. Dedju (1980) reported presence of Gammarus pulex in Crimean Peninsula, G. lacustris in the entire Dnieper River system, G. balcanicus in the Carpa-thian Mountains, Dniester system and tributaries of the upper Southern Bug River, and G. kischinef-fensis from the Dniester system. Jazdzewski & Ko-nopacka (1988, 1989) discussed the distribution of G. balcanicus, G. kischinefensis and newly erected G. leopoliensis in the upper Dniester basin.

Gammarus varsoviensis Jazdzewski, 1975 is a species described originally from the vicinity of Warsaw, in Central Poland. Until now the species has been recorded from Central European low-lands (Fig. 1), ranging from the right tributaries of the Elbe River (North Sea basin) in Germany on the west, through Oder and Vistula river systems in Poland, Nemunas River in Lithuania to Dau-gava River (Baltic basin) in Latvia on the east; only few localities were recorded so far from the upper Pripyat River (Black Sea basin) in Belarus (Jaz-dzewski 1975, Jazdzewski 1980, Jazdzewski & Ko-nopacka 1995, Arbaciauskas 2008, own unpub-lished data). Jazdzewski (1980) as well as Vainio et al. (1995) noticed that G. varsoviensis distribution range does not conform to any general zo-

Grabowski, M. et al.

ogeographical pattern among native European inland water animals (e.g. Illies, 1978). The above authors hypothesized that it might be a recent immigrant from sources outside central Europe, expanding its range through the canal network connecting various river systems. Unfortunately, due to lack of data outside the area, no further conclusions could be derived.

In August 2009, during collecting trip to Ukraine, we un-expectedly found several populations of Gammarus show-ing diagnostic features of G. varsoviensis and inhabiting rivers of the middle and the lower Dnieper River drain-age system, within the Black Sea basin (Table 1, Fig. 1). Qualitative samples of amphipods were collected with benthic hand-net from all available habitats at each site. The materials were fixed in 96% ethanol, identified to species level based on available literature (Jazdzewski 1975, Karaman & Pinkster 1977) and stored in the collec-tion of the Department of Invertebrate Zoology & Hydro-biology, University of Lodz. Subsequent collecting trip in

2011 did not reveal any further records of the species in other studied rivers.

All new records of G. varsoviensis come from small and medium size lowland rivers, flowing through forest and grassy areas, with slow current, sand-muddy bottom and dense vegetation (Fig. 2). Such conditions are identical to those in which it was found in Poland, Germany, Lithuania and Belarus (Jazdzewski 1975, Arbaciauskas 2008, own unpub-lished data).

A question arises, why the species was not re-corded earlier from this vast area, extending the known geographic range of this species ca. 830 kilometers south-east? In our opinion it was sim-ply overlooked, first of all for its close resemblance to Gammarus lacustris, from which it was not iden-tifiable for a long time (Jazdzewski 1975). The two species may be separated mainly through rather

Table 1. Findings of Gammarus varsoviensis in Ukrainian rivers (* population that co-exists with G. lacustris).

Station number

Decimal Latitude

Decimal longitude

Altitude (m asl)

Locality Date

1 51.73574 25.49367 146 Stochid River near Lubeshiv town 09.08.2009 2* 51.84818 25.47230 147 Pripyat R. near Lyubyaz village 09.08.2009 3 51.77030 25.35393 148 Korostianka R. near Derevok vill. 09.08.2009 4 51.22880 26.36290 152 Horyn R. near Krychyls’k village 10.08.2009 5 50.84359 29.81191 133 Teteriv R. near Blidcha vill. 11.08.2009 6 50.88941 29.98299 125 Tal R. near Rudnya-Shpylivs'ka vill. 11.08.2009 7 50.68513 31.11143 91 Krezen R. near Zavorici vill. 26.08.2009 8 47.69575 35.57920 25 Konka R. near Dymitrovka vill. 14.08.2009

Figure 1. Distribution of Gammarus varsoviensis in Europe. Grey circles – previously known records of the species (combined literature and own data). White circles with numbers – localities of G. varsoviensis in Ukraine revealed during 2009 survey (numbers on data points correspond to the station numbers in Table 1). White triangles – other localities in Ukraine studied during 2009 and 2011 surveys, where no G. varsoviensis was found.

First records of Gammarus varsoviensis in Ukraine

Figure 2. Habitats of Gammarus varsoviensis in Ukraine: A – Pripyat River near Lyubyaz village, B – Horyn River near Krychyls’k village, C – Tal River near Rudnya-Shpylivs'ka village, D – Konka River near Dymitrovka village (photo: Michal Grabowski).

Figure 3. Morphology of antenna II and telson in Gammarus varsoviensis (A, C) and G. lacustris (B, D). Arrow indicates shape and position of antennal gland cone (after Karaman & Pinkster 1977, modified).

subtle, yet clear morphological differences in shape of the gland cone on peduncle of second an-tenna, curved upwards in G. varsoviensis and straight in G. lacustris, as well as armature of uro-some and telson – with long setae in G. varsovien-sis, and short ones in G. lacustris (Fig. 3). That, combined with an apparent lack of access to con-temporary literature, was apparently the reason for which Dedju (1980) reported only G. lacustris from the entire Dnieper drainage area. In fact, dur-ing the recent sampling we have found this spe-cies only in the upper Pripyat River, where it co-occurred with G. varsoviensis (Table 1, Fig. 1) in almost stagnant water just below Lyubyaz Lake,

through which the river passes. Generally, G. lacustris is a species with a vast geographical range encompassing Eurasia and boreal part of North America (Karaman & Pinkster 1977). In northern parts of its range (e.g. Central Europe, Siberia), it occurs predominantly in lakes and lowland rivers, while more south it thrives only in alpine lakes. Thus we can conclude that in reality, G. lacustris probably occurs in Ukraine only in the northern part of the country, while all other old records can be attributed to G. varsoviensis. Such distribution implies a possibility that geologically old Dnieper system may be in fact a home range for the species from which it subsequently colonized northern

Grabowski, M. et al.

and western parts of its present range, covered with ice sheet during the Pleistocene. In fact, all rivers of the Black Sea drainage area in which the species was found have been connected to the Dnieper system through artificial navigable canals since the XVIII/XIX century (Bij de Vaate et al. 2002). If such, then the species would be yet an-other alien aquatic species recently colonizing Central Europe from the Black Sea basin (Borza et al. 2011, Semenchenko et al. 2011). Acknowledgements: Thanks are due to Natasha Rubtsova for her help in collecting samples during the 2009 survey, performed and founded within the Polish Ministry for Science & Higher Education, grant no. N N304 081 535. The fieldwork in 2011 was partially funded by Polish Ministry for Science & Higher Education, grant no. N N304 350 139 and partially by the private funds of Radomir Jaskula within the 6th TBQuest expedition that he organized and led. Thanks are due to him and Marek Michalski for help in gathering samples during that trip. Wanda and Manolis Plaitis are wholeheartedly thanked and credited for hospitality in their house in Crete, Greece, allowing us to analyse the results and prepare the manuscript on their terrace in summer 2011. Finally, thanks are due to Dr. Manfred Pöckl and Dr. Kresimir Zganec for reviewing the manuscript. References Arbaciauskas, K. (2008): Amphipods of the Nemunas River and the

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