Distribution of Cladocera Species in Different Waters of Turkey

Species diversity and distribution of Cladocera collected from river, dam lake, lake, marshes and well, in different regions of Turkey have been reported. Fortyfour samples collected from 31 different localities contained 37 species belonging to six families. Chydoridae was the most species rich family with 18 species followed by Daphniidae with 11 species. Bosmina coregoni, a rare species for Turkey inland waters, is a new record for Mediterranean region of Turkey.


Introduction
The Cladocera species, which create an important proportion of zooplanktonic organisms, are found in almost all kind of aquatic habitats such as rivers, lakes, ponds, streams, wetlands and other bodies of water.Cladocerans are known as essential components of the food chain for the freshwater ecosystem, because they are the most important grazers of phytoplankton, and thus herbaceous material is diverted to animal material through these zooplankton.For this reason, these species are biological indicators of the water systems where they are found (Güher 2000).On the other hand, living cladoceran communities and their fossil remains preserved in lake sediments reflect their aquatic habitat in similar ways (Kattel et al. 2006; Davidson et al. 2007).
Cladocerans are small-sized (0.2-6 mm) except Leptodora kindtii, branchiopod crustaceans, inhabiting pelagic, littoral, and benthic zones.Four cladoceran orders are recognised (Frey 1987): Anomopoda, Ctenopoda, Onychopoda, and the monotypic Haplopoda.The trunk and appendages of most cladocerans (Anomopoda and Ctenopoda) are enclosed in a bivalved carapace.Tagmosis of the body is mostly obscure, and a single eye and ocellus are usually present.Cladocerans are important components of the fauna of fresh waters; they are particularly significant in the food web of stagnant waters.
Most species are filter-feeders; onychopods and haplopods are predatory.They usually reproduce by cyclical parthenogenesis, and populations are mostly dominated by females.Sexual dimorphism is normally rather distinct.Sexually produced diapausing eggs are resistant to desiccation and other unfavourable conditions, and may even survive passage through the digestive track of birds (Figuerola and Green 2002); thus, they are important propagules for passive dispersal (Forro et al. 2008).

Materials and Methods
The samples of cladocerans were collected from 31 different freshwater localities using 60 μm plankton net.The samples were fixed with 4% formaldehyde.An Olympus CH40 microscope and a camera were used for drawings of the species.Measurements were made with a Zeiss microscope and camera.Body measurements of Bosmina coregoni specimens were made from head to end of mucro, and carapace height.The species were identified with the aid of Scourfield and Harding (1966), Smirnov (1974), Negrea (1983), Korinek (1987) and Pennak (1989).All sampling points are freshwater except Titreyen Lake (Side, Antalya), slightly brackish water in the property.The sampling localities and sampling dates are given in Table 1.
Body of female Bosmina coregoni short and wide (Figure 1A), with length 0.54-0.90mm.Carapace sculptured with longitudinal lines on the head shield.Highness of valves about 1.5 times that of body.Valves with evenly curved dorsal edge.Ventral edge of valve slightly convex, with a series of stout setae, the bases of which are located on its internal surface.
Posterior edge practically straight, about 2.5 times shorter than largest length of valve.Mucro (Figure 1B) spiniform, relatively short, its basis considerably extended.On its tip, two concentric series of pointed tubercles.Frontal edge of head convex, rostrum short and blunt.Antennules rather short, slightly folded, posteriorly directed, with powerful basis and pointed tips.Frontal sensory setae relatively long.Frontal head pore located between these setae, the median pore on the frontalmost point of the head (Figures 1C).
Second antennae with powerful basal part, with cross series of denticles and short branches, and also girdled by similar rows.Lateral head pore located near articulation of mandible.Eye of female roundish, large, located closer to basis of second antenna than to frontal edge of head.Postabdomen of adult female strongly compressed, lamelliform, its width equal along all its length (Figure 1Da).Distal edge nearly directly truncated.Anus opening on this edge as a long, wide, vertical slit.
A conical projection with two long postabdominal claws on ventral surface of postabdomen (Figure 1Db).A row of rather large denticles present on their basal part, continued in a group of 3-5 small-sized denticles on base of claws (Figure 1Db).Several rows of thin delicate setae located on internal and external surface of claws.Back and dorsal edges of postabdomen covered by cross interrupted series of relatively long thin setules (Figure 1Dc).Such series present near basis of postabdomen on the plate, situated over the post-abdominal setae.
B. coregoni, rare species inland waters of Turkey, was reported first time by Güher and Kırgız (1989) from Edirne province inland waters, and later it was reported by Özbay and Kılınç (2008) from Aktaş Lake (Ardahan).
It was reported third times from Turkey, B. coregoni is widespread, small-bodied, filter-feeding cladocerans common in the open-water areas of both the littoral and pelagic zones of oligotrophic and mesotrophic freshwater lakes and ponds, and distributed in the northern and middle holarctic (DeMott and Kerfoot 1982).
The presence and distribution of the species in the study even holarctic B. coregoni is quite closely related to the ecological characteristics of the species, and all species in the study are widespread.

Table 1 .
Sampling localities and sampling dates.

Table 2 .
Detected species and localities.