Candona Neglecta Research Articles

Ostracodes Fauna from Core Sediments of Surinsar Lake of Jammu:TheirPalaeoecological andPalaeoclimatic Implications

Surinsar Lake is one of the deepest fresh water lake situated in the Lower Siwalik Subgroup of Jammu, Jammu and Kashmir, India. In the present study,nine species of ostracodes have been recovered from the core sediments of Surinsar Lake, Udhampur district, Jammu and Kashmir, India. These species are identified as Candona candida, C. lactea, C. neglecta, Stenocypris sp., Cypris subglobosa, Cypridopsis sp., Hemicypris pyxidata, Jlyocypris gibba, Potamocypris sp. based on their morphological characters. Out of nine species, four species Candona lactea, Candona neglecta, Jlyocypris gibba and Stenocypris sp., has been already reported from Surinsar Lake and five ostracodes species Hemicypris pyxidata, Potamocypris sp., Cypris subglobosa, Candona candida, Cypridopsis sp. are recovered in addition to already reported species. A brief account on the palaeoecologic and palaeoclimatic implications of fauna recovered is discussed in the present study. Keywords: Ostracodes, Core Sediments, Fresh Water Lake, Surinsar, Lower Siwalik Subgroup, Jammu, India

A modern snapshot of the isotopic composition of lacustrine biogenic carbonates – records of seasonal water temperature variability

Abstract. Carbonate shells and encrustations from lacustrine organisms provide proxy records of past environmental and climatic changes. The carbon isotopic composition (δ13C) of such carbonates depends on the δ13C of dissolved inorganic carbon (DIC). Their oxygen isotopic composition (δ18O) is controlled by the δ18O of the lake water and by water temperature during carbonate precipitation. Lake water δ18O, in turn, reflects the δ18O of atmospheric precipitation in the catchment area, water residence time and mixing, and evaporation. A paleoclimatic interpretation of carbonate isotope records requires a site-specific calibration based on an understanding of these local conditions. For this study, samples of different biogenic carbonate components and water were collected in the littoral zone of Lake Locknesjön, central Sweden (62.99∘ N, 14.85∘ E, 328 ma.s.l.) along a water depth gradient from 1 to 8 m. Carbonate samples of living organisms and subfossil remains in surface sediments were taken from the calcifying alga Chara hispida, from bivalve mollusks of the genus Pisidium, and from adult and juvenile instars of two ostracod species, Candona candida and Candona neglecta. Our results show that neither the isotopic composition of carbonates nor the δ18O of water vary significantly with water depth, indicating a well-mixed epilimnion. The mean δ13C of Chara hispida encrustations is 4 ‰ higher than the other carbonates. This is due to fractionation related to photosynthesis, which preferentially incorporates 12C into the organic matter and increases the δ13C of the encrustations. A small effect of photosynthetic 13C enrichment in DIC is seen in contemporaneously formed valves of juvenile ostracods. The largest differences in the mean carbonate δ18O between species are caused by vital offsets, i.e., the species-specific deviations from the δ18O of inorganic carbonate which would have been precipitated in isotopic equilibrium with the water. After subtraction of these offsets, the remaining differences in the mean carbonate δ18O between species can mainly be attributed to seasonal water temperature changes. The lowest δ18O values are observed in Chara hispida encrustations, which form during the summer months when photosynthesis is most intense. Adult ostracods, which calcify their valves during the cold season, display the highest δ18O values. The seasonal and interannual variability in lake water δ18O is small (∼ 0.5 ‰) due to the long water residence time in the lake. Seasonal changes in the temperature-dependent fractionation are therefore the dominant cause of carbonate δ18O differences between species when vital offsets are corrected. Temperature reconstructions based on paleotemperature equations for equilibrium carbonate precipitation using the mean δ18O of each species and the mean δ18O of lake water are well in agreement with the observed seasonal water temperature range. The high carbonate δ18O variability of samples within a species, on the other hand, leads to a large scatter in the reconstructed temperatures based on individual samples. This implies that care must be taken to obtain a representative sample size for paleotemperature reconstructions.

Evidence of Predation on Early Pleistocene Freshwater Ostracods (Umbria, Central Italy)

Although drillholes in modern and ancient ostracods are known, the record is relatively scarce when compared to other taxa, and mainly exist with reference to the marine environment. Moreover, less is known about perforated ostracods, and more generally, about bioerosion in freshwater environments. Traces of predation on freshwater ostracods are reported for the first time in deep-lake deposits belonging to the early Pleistocene Fosso Bianco Unit, and outcropping in the Cava Nuova section (Umbria, central Italy). Deposits are mainly clay to silty clay and sand; the fossil record is sparse, and is mainly comprised of very rare gastropods and bivalves, ostracods and plant remains (leaves, seeds and wood’s fragments). The association of ostracods consists of Candona (Neglecandona) neglecta, Caspiocypris basilicii, Caspiocypris tiberina, Caspiocypris perusia, Caspiocypris tuderis, Caspiocypris posteroacuta, and Cyprideis torosa. The Caspiocypris group, considered to be endemic to the grey clays of the Fosso Bianco Unit, present the majority of specimens affected by predation, with a prevalence of predated female valves and a comparable number of right and left predated valves, while only a few of Candona(N.) neglecta (adult and juvenile) valves are perforated. Traces of predation for nourishment, represented by microborings of different types, were abscribed to the ichnospecies Oichnus paraboloides Bromley 1981, Oichnus simplex Bromley 1981, Oichnus gradatus Nielsen and Nielsen 2001, Oichnus ovalis Bromley 1993, and Dipatulichnus rotundus Nielsen and Nielsen 2001. Microboring affected both adult and juvenile specimens, evidencing prey–predator coexistence in the same environment over a long period of time. This report makes a fundamental contribution to the knowledge of predation in this peculiar confined environment, also suggesting prey–predator relations over a relatively short time interval (80–160 ka).

Species assemblages of Ostracoda (Crustacea) from west-site of Turkey: their indicator potential for lotic and lentic habitats

To describe the indicator potential of non-marine ostracods for lotic (streams) and lentic (lakes) habitats, 42 taxa (27 recent, 15 subfossil) were evaluated from 62 sampling sites in West-site of Turkey during May of 2018. Nannocandona faba is a new report for Turkey. A higher Shannon diversity value was reported for lakes (H′ = 2.16) than streams (H′ = 1.62) when they had equal number of species (17 spp.). SIMPER analysis showed 53.01% contribution of Psychrodromus olivaceus, Candona neglecta, Heterocypris incongruens and Stenocypria fischeri with a 96.72% difference between lakes and streams. Both TWINSPAN and Indicator Species Analysis revealed that P. olivaceus (p < 0.01) and S. ficheri (p < 0.05) were found to be candidate indicators for the lotic and lentic habitats, respectively. The first two axes of CCA explained 66.90% of the relationship between species and environmental variables when elevation, dissolved oxygen concentration and water temperature showed influential effects (p < 0.05) on the ordination of species. Species with reduced swimming setae (17 spp.) were ordinated relatively closer to the center of CCA. Results showed that ecological tolerances of species seemed to be more deterministic than morphological characters (e.g., swimming setae) on their habitat preferences. A broad knowledge of the morphological and ecological preferences of the species is needed to distinguish whether habitat is chosen by species due to its ecological needs or morphological characteristics. Studies providing information about the current ecological preferences of the species give the opportunity to understand the habitat of these species.

Holocene marginal marine ostracod successions from the Kızılırmak River delta; Implications for depositional environments and sea-level changes at the Southern Black Sea coast

Holocene delta formations are unique records of regional sea-climate interactions. The Kızılırmak Delta is the biggest and richest wetland ecosystem in the Black Sea region of Turkey. The Black Sea was uniquely affected by rising sea levels due to its disconnection from the world oceans during the last glacial period. To understand the palaeoenvironmental impact on the delta plain we analysed a 14.5-m-long sediment core using palaeoecological ostracod analyses accompanied by a palaeo-salinity reconstruction based on sieve pore analysis on the ostracod Cyprideis torosa. This study depicts the interplay of terrestrial and marine settings forming mesohaline, shallow lagoons and deltaic lakes since ca. 7.9 ka cal BP. Lagoons with α-mesohaline to polyhaline salinities and β-mesohaline to oligohaline lake environments were identified. Reconstructed palaeo-sea level estimations depict a remarkable environmental variability. The lagoon habitats at 7.9 to 7.0 and 5.3 to 4 ka cal BP were dominated by Cyprideis torosa. Marine influence led to ostracod associations with Loxoconcha spp. and Tyrrhenocythere amnicola especially between 7.9 and 7.0 ka cal BP. Riverine influence in the same period, but especially at about 7.7 ka cal BP, caused dominating Amnicythere spp. Cyprideis torosa and Candona neglecta that characterise short phases of a mesohaline deltaic lake environment at about 7.7 and 7.0 ka cal BP as well as after 4 ka cal BP. With a subsequent salinity decrease, C. neglecta and (later on) Pseudocandona marchica became dominant with an interruption by another short-term lagoonal phase that might be associated with a ‘megadrought’ between 3.7 and 3.0 ka cal BP.

Comparative analyses of non-marine ostracods (Crustacea) among water basins in Turkey

Total of 26, 22 and 32 sites in Konya, Antalya and West Mediterranean basins in Turkey, respectively, were sampled twice during 2017 to compare the non-marine ostracod diversity. A total of 1787 individuals belonging to 31 species were recorded from all basins. Of which, nine species are common among basins when Fabaeformiscandona fragilis is new for Turkey. High species diversity was found at middle elevational intervals. The highest and lowest Shannon diversity index values were recorded for both Konya (H = 2.19) and Antalya (H = 1.90) basins, respectively. The highest beta diversities values are encountered between closed the Konya and other open basins. Species and environmental variables composition among basins and elevational intervals showed significant differences (p < 0.05, ANOSIM). Of species, cosmopolitans (e.g., Candona neglecta, Ilyocypris bradyi, Psychrodromus olivaceus) provide an important contribution to the differences in diversities among basins and elevational intervals. According to Canonical Correspondence Analysis, elevation appeared to be the common influential variables in all basins. Results suggest that alpha diversity is under the control of local and regional factors when beta diversity is primarily affected by regional factor. Although cosmopolitan species are positive indicators, they seem to make a significant contribution to alpha and beta diversities of ostracods.

Piacenzian–Gelasian non‐marine ostracods from the Dunarobba Fossil Forest (Tiberino Basin, Umbria, central Italy)

AbstractThe taxonomy of some non‐marine ostracod assemblages from the Dunarobba Fossil Forest area (south Tiberino Basin, Umbria, Italy) is discussed, adding to the scientific understanding of Piacenzian–Gelasian non‐marine ostracods in central Italy and providing a palaeoenvironmental reconstruction of the shallow coastal lacustrine environments of the Palaeolake Tiberino. The ostracod assemblages include Darwinula stevensoni, Vestalenula cylindrica, Candona (Candona) improvisa, Candona (Neglecandona) neglecta, Candona (Neglecandona) angulata, Candona (Neglecandona) paludinica, Caspiocypris basilicii, Caspiocypris tiberina, Candonopsis kingsleii, Cyclocypris ovum, Ilyocypris bradyi, Ilyocypris decipiens, Cypris mandelstami, Zonocypris membranae quadricella, Potamocypris fulva, Cyprideis crotonensis, Cyprideis rectangularis and two new species: Hemicypris lomastroi sp. nov. and Paralimnocythere turgida sp. nov. In addition to widespread European species, the ostracod assemblages contain some rare species that were previously known from the Pliocene Paludinian Beds of Serbia. A cluster analysis applied to the ostracod frequency matrix has lead to the identification of four separate assemblages that can be attributed to several ecological niches, including emerged hydrosols, ephemeral coastal pools and a littoral lacustrine margin, which suggest a complex coastal environment.

Elevational distribution and species diversity of freshwater Ostracoda (Crustacea) in Çankırı region (Turkey)

We investigated how the richness and ecological characteristics of non-marine ostracod species varied across nine 100-m elevation bands (from 549 to 1457 m) in the Çankırı region. We collected a total of 37 taxa (25 living and 12 sub-recent) from 114 of 130 aquatic sites sampled during September of 2011; 34 of the taxa were new records for the region. Eight widely distributed ‘cosmopolitan’ species (Candona neglecta, Cypridopsis vidua, Heterocypris incongruens, Ilyocypris bradyi, Limnocythere inopinata, Potamocypris villosa, Prionocypris zenkeri, and Psychrodromus olivaceus) were found more frequently than other species. The first two axes of canonical correspondence analyses (CCA) explained 73.2% of the correlation between 11 species and 5 environmental variables. Of which, electrical conductivity (F = 3.99, p = 0.028) and altitude (F = 2.69, p = 0.004) were the most explanatory (p < 0.05) variables for species. Optimum altitude and water temperature values of the cosmopolitan species were relatively higher than the other species. Significant regression models (p < 0.01, r2 = 0.81) indicate that the frequency of occurrence was affected by changes in numbers of samplings sites from 549 to 1457 m. When highest numbers of species (15 spp.) were found at the range of 1231–1332 m, numbers of asexual species (10 spp.) were twice of the sexual species (5 spp.) with no statistical difference between numbers of swimming (7 spp.) and non-swimming (8 spp.) species. Results were discussed based on the ecological conditions that individual species prefer.

Effects of river bed regulation on habitats and communities: A case study for ostracods in the Oder River, Poland

The effects of damming, groyne building, and channelizing on habitats and ostracod assemblages in the Oder River, one of the six largest European river systems, were analyzed. Regulation works had been conducted on the river from the 18th to the beginning of the 20th century. Main objectives of the study were to detect the effect of river bed regulation on attributes of habitats and ostracod communities. The values of nitrogen were the highest in the dammed stretch and the lowest in the channelized one. As for conductivity, TDS (total dissolved solids) and salinity were the highest in the groyned stretch. Hardness had the highest values in the channelized and groyned stretches. The lowest visibility was noted in the dammed stretched. The stretch influenced by damming was dominated by habitats with a considerable proportion of detritus in sediments. In the stretch influenced by groynes, the proportions of habitats with mineral and organic substrates were similar and the proportion of habitats covered with vegetation was the highest. Habitats with rocky, sandy bottoms dominated in the channelized stretch and nearly half of the habitats were covered with vegetation. The highest ostracod density characterized the groyned stretch (658 ind · m−2), was moderate in the case of the dammed stretch (290 ind · m−2) and the lowest in the channelized one (107 ind · m−2). Bradleystrandesia reticulata, Candona neglecta, and Limnocythere inopinata dominated in the groyned and channelized stretches. Cypridopsis vidua, Darwinula stevensoni, and Pseudocandona compressa dominated in the dammed stretch. The type of river bed regulation significantly differentiated both habitats and ostracod assemblages. Differences among ostracod assemblages were related to particular species, but also regarding density and evenness. The degree of vegetation coverage and detritus content in the sediments were strong predictors for ostracod community composition.

Palaeoenvironmental inferences from late Quaternary sediments of the Al Jafr Basin, Jordan

Sedimentological, palaeontological and mineralogical analyses of sediments from the endorheic Al Jafr Basin were conducted to better understand the depositional and hydrological conditions on the southern Jordan Plateau in the late Quaternary. Surficially exposed carbonate-rich sediments in the western part of the basin contain ostracod (micro-crustacean) shells of Ilyocypris cf. bradyi, Candona neglecta, Heterocypris salina, Fabaeformiscandona fabaeformis, Pseudocandona sp. and Herpetocypris brevicaudata. The shells of these and other more rare species, and charophyte and mollusc remains indicate that the sediments were formed in a wetland setting of shallow freshwater to slightly oligohaline ponds, streams and swamps. The present more northern distribution of some of the recorded taxa implies that climate conditions were probably cooler during the wetland formation. Radiocarbon age data for biogenic carbonate from two locations suggest that the wetland setting existed during the second half of Marine Isotope Stage (MIS) 3 or possibly earlier. A significantly higher water table must have existed in the basin during wetland formation; and wetter climate conditions are inferred for the catchment or at least for its highest and most humid westernmost part. Deflation and local sediment accumulation by wind and occasional sheet-wash events apparently prevailed in the region since MIS 2. Our newly presented data and inferences do not support the reconstruction of a previously reported large and relatively deep Pleistocene lake in the Al Jafr Basin. However, more extensive studies are certainly required for a detailed assessment of the Quaternary hydrological conditions in southern Jordan.

Distributional patterns of non-marine Ostracoda (Crustacea) in Adiyaman Province (Turkey)

To understand the distribution and ecological characteristics of non-marine ostracods, the Poisson Method was applied to a total of 41 taxa (26 recent and 15 sub-fossil) from 111 (out of 120) aquatic bodies of Adiyaman Province, Turkey. All taxa were new records for the area and Schellencandona insueta and Gomphocythere n. sp. were the first records for Turkey. According to the Poisson method, ostracods were randomly distributed among all sampling sites (P >0.05). This is especially true for the cosmopolitan species (Candona neglecta , Heterocypris incongruens , Ilyocypris bradyi and Psychrodromus olivaceus ) with broader ecological tolerance ranges to different environmental variables. According to canonical correspondence analysis (CCA), the first two axes explained 77.4% of the relationships and the most effective variables were found as electrical conductivity (F =3.987, P =0.002, λ=0.31), water temperature (F =3.582, P =0.002, λ=0.17), pH (F =3.510, P =0.002, λ=0.12) and elevation (F =4.491, P =0.02, λ=0.37). Additionally, the ratio (numbers of taxa/site =2) was found same at lower (450–550 m) and higher (1359–1459 m) ranges, in which H. incongruens and I. bradyi were the most common species found from different habitats. Overall, random distribution of ostracods among sampling sites seemed to be more affected by random distribution of cosmopolitan species at the regional level than the non-cosmopolitans whose distribution may be uniform or clumped since they prefer certain types of ecological conditions at local level.

Early Pleistocene (Calabrian) Ostracoda assemblage and paleoenvironmental characteristics of the Fevzipasa Formation,Western Anatolia

The study area is located about 40km west ofAydin city in western Turkey and includesNeogene to Quaternary sediments of the Fevzipasa Formation, which unconformably overlies the Miocene rock units. The Fevzipasa Formation is composed of conglomerates, sandstones, mudstones, marls, limestones and tuff layers and is unconformably overlain by recent deposits of the Söke-Milet Basin. The lower part of the Fevzipasa Formation is represented by coarse clastics and lacustrine carbonates followed by fine to coarse-grained sandstones bearing mollusc shells. Prominent tuff layers (lower and upper tuff layers) of this dominantly sandstone succession were radiometrically dated between roughly 2 and 1Ma. Based on small mammal fauna the age of the upper part of the formation is Early to Late Pleistocene. To investigate the paleoenvironmental evolution of the succession, forty-two samples were collected along two stratigraphic sections. Ostracoda assemblages together with Chara flora, Gastropoda and Pelecypoda and fish remains were recovered from only twenty-nine samples. Ostracoda assemblages include Candona neglecta, Cyclocypris ovum, Ilyocypris gibba, I. bradyi, Heterocypris salina and Scottia cf. S. pseudobrowniana. Additionally, fish remains belonging to the Cyprinidae family (Tinca sp., Leuciscus sp. and Leuciscus etilius) and Characeae gyrogonites referable to Nitellopsis obtusa, Chara sp., C. aspera, C. globularis, C. hispida, C. vulgaris, Lychnothamnus sp. and Sphaerochara sp. occurred in the samples. The ostracod, fish, and gyrogonite records all indicate that the Fevzipasa Formation was deposited in a paleoenvironmental setting characterized by permanent and shallow water bodies. According to the identified Ostracoda assemblages and combining all available stratigraphic data, the age of middle part of the Fevzipasa Formation is suggested as Early Pleistocene (Calabrian).

BİRECİK BARAJ GÖLÜ HAVZASI (ŞANLIURFA) VE HAZAR GÖLÜ(ELAZIĞ) OSTRACODLARI (CRUSTACEA) HAKKINDA ÖN ÇALIŞMA

In this study, the samples which collected from The Birecik Reservoir Basin and Lake Hazar were examined. As a result, 11 species from Birecik Reservoir Basin (Darwinula stevensoni (Brady & Robertson,1870); Candona neglecta Sars, 1887; Candona angulata Muller, 1900; Fabaeformiscandona sp.; Pseudocandona cf albicans; Cryptocandona sp.; Ilyocypris sp.; Heterocypris salina (Brady, 1868); Potamocypris sp.; Limnocythere inopinata (Baird,1843); Kovalevskiella sp.) and 3 species from Lake Hazar (Candona neglecta Sars, 1887; Candona sp.; Limnocythere inopinata (Baird, 1843)) were found. All of these species are new records for The Birecik Reservoir Basin and Lake Hazar

Palaeoecology of Late Glacial and Holocene profundal Ostracoda of pre-Alpine lake Mondsee (Austria) — A base for further (palaeo-)biological research

Succession of profundal ostracod palaeoassemblages in response to environmental changes during the Late Glacial and Holocene was studied in a~15-m-long sediment sequence from pre-Alpine lake Mondsee (Austria). First local ostracod assemblage zone LOAZ-1 (prior to 15,700 a BP), with low abundances of Leucocythere mirabilis and Limnocytherina sanctipatricii followed by Cytherissa lacustris, corresponds to the Pleniglacial phase of clastic-detrital sedimentation at relatively high rates. Most of the key species of LOAZ-2 (15,590 to 13,940 a BP, including the Pleniglacial–Late Glacial transition), i.e. limnocytherids, Fabaeformiscandona cf. harmsworthi, F. tricicatricosa, C. lacustris and Candona candida, reveal the significant association with high Al contents and low sedimentation rates and are classified as preferring low-productivity conditions. In contrast, Candona neglecta, dominant in LOAZ-3 (13,820 to 9960 a BP, palynologically defined as Bölling–Early Holocene) and in the last LOAZ-4 (9780 a BP to present) as well as Cypria ophtalmica (second key species in LOAZ-4) show relationship with higher productivity, elevated sedimentation rates and decreasing Al contents.Furthermore, valve biodegradation and shape disparity at different time periods and in relation to sedimentation rate changes were investigated in A-3 juveniles of Candona neglecta. The highest percentage of valves biodegraded by Actinobacteria was recorded during the Allerød, Younger Dryas and Early Holocene, when the lowest sedimentation rates occurred, whereas significantly lower frequencies of biodegraded valves were recorded during the mid-Holocene and Late Holocene, when sediment accumulation was much higher. It is also hypothesised that the degree of the valve shape variation was related to the lake productivity. During the Allerød, Younger Dryas and Early Holocene a valve shape variation significantly lower than that recorded during Late Holocene intervals, characterised by intensified lake productivity, was observed. Additionally, an agenda of potential questions and approaches that should be considered and form the core of further (palaeo-)biological research projects is offered.

The Middle Palaeolithic Nahal Mahanayeem Outlet site, Israel: reconstructing the environment of Late Pleistocene wetlands in the eastern Mediterranean from ostracods

We present ostracod data from the Middle Palaeolithic open air site of Nahal Mahanayeem Outlet (NMO) at the southern edge of the Hula Basin, northern Israel.Sediments of two Pleistocene water bodies are exposed at the site. The first one is an archaeologically sterile, light-colored limnic carbonate with an Early Pleistocene age. It contains an ostracod fauna assemblage dominated by Candona neglecta, Candonopsis kingsleii, and Pseudocandona sp., and, in minor abundances, Cypria ophtalmica, Cyprideis sp., Humphcypris sp., Fabaeformiscandona cf. fabaeformis and Ilyocypris sp. These sediments were deposited in a shallow, freshwater to oligohaline lake under stable conditions.Sediments of the second water body are silty and dark-colored with a depositional age of 65 ka, belonging to the Late Pleistocene Ashmura Formation. The unit covers a geologically complex topography of tectonically uplifted limnic deposits and a hill-like gravel bar at the site. The most important archaeological layer is situated at its base, containing a lithic assemblage ascribed primarily to the Middle Palaeolithic Mousterian tradition and very well preserved flora and fauna. In the sediments from the archaeological layers, the brackish water ostracod Cyprideis torosa and the foraminifer Ammonia tepida could be identified. In sediments of the Ashmura Formation taken near the site, C. neglecta, Candona angulata, Ilyocypris sp., C. kingsleii, Pseudocandona sp., C. ophtalmica, Darwinula stevensoni, Trajancypris sp. and Potamocypris smaragdina were found, indicating a freshwater to slightly oligohaline stagnant water body.The ostracod fauna of the NMO site, together with geochemical data, allow us to reconstruct a depositional environment of the margin at a shallow lake with brackish or saline springs nearby during the site's occupation by Middle Palaeolithic humans.Additionally, Candona weltneri, Candona cf. meerfeldiana, C. kingsleii, Cyclocypris laevis, C. ophtalmica, Cyprideis sp., Fabaeformiscandona cf. fabaeformis, P. smaragdina, Pseudocandona depressa, Trajancypris sp, Zonocypris cf. costata and A. tepida could be recorded for the first time for the Pleistocene limnic strata of the Hula Basin.

The dynamics of seasonal ostracod density in groyne fields of the Oder River (Poland)

The study investigated seasonal dynamics of the ostracod population in the Oder River (Poland), in the area of groyne fields. Groyne fields were lenitic areas in that river system, providing favourable conditions for ostracod development. The main aims of the study were to find information on seasonal differences in ostracod occurrence, determine models of density dynamics and become acquainted with the effect of environmental factors on seasonal changes of ostracod assemblages. Samples were collected from 15 research stations in the littoral. The respective zones of the groyne fields abounded in various microhabitats. Average density, frequency coefficient, dominance, Shannon-Wiener diversity index (H), and Pielou’s evenness index (J) were calculated for Ostracoda assemblages in order to point out differences between seasons. In total, 237 samples were collected; forty-seven species were identified, and the average density was 658 indiv. was studied during the vegetation season. The highest average density of the ostracods was discovered in spring (1160 indiv. m-2) with maximum of 9472 indiv. m-2.); in the subsequent seasons it dropped by about half. The density dynamics of particular Ostracoda species was often different from their overall density. Significant differences between seasons were discovered with regard to the number of taxa, density and evenness index. The species that dominated throughout the year included Limnocythere inopinata and Physocypria kraepelini. Furthermore, juvenile Candoninae dominated in spring, Cypridopsis vidua dominated in summer, and Candona neglecta, C. vidua and juvenile Pseudocandona dominated in autumn. It turned out that the dynamics of occurrence of certain species observed in the present study contradicted data from literature related to the following species: Darwinula stevensoni, Cypria ophtalmica, Physocypria kraepelini, Limnocythere inopinata. All obtained models of density dynamics pointed out maximum density in spring, indicating that during that period the conditions in the river were optimal for ostracod development, as confirmed by the results of studying environmental factors. Ecological condition of the Oder was also good in the other seasons. Temperature, visibility, and dissolved oxygen content were among factors which most strongly affected ostracod assemblages. Availability of organic matter could result in decreasing their density.

Effects of limnoecological changes on the Ostracoda (Crustacea) community in a shallow lake (Lake Çubuk, Turkey)

Abstract We sampled Lake Cubuk, a shallow lake in Bolu (Turkey), for 26 months to investigate the effect of limnoecological changes on the composition of ostracod species. Seventeen ostracod species were identified from the six stations sampled between 2008 and 2010. Numbers of species and individuals were both significantly reduced during 2010, which corresponded to a 3 m water level increase. Ostracod Watch Model (OWM) displayed distinct seasonal occurrences of five species (Candona neglecta, Cypria ophtalmica, Cypridopsis vidua, Limnocythere inopinata, Fabaeformiscandona cf. japonica) when Physocypria kraepelini was the only species encountered all year round. Approximately 77.2% of the relationship between species and environmental variables was expressed by the first two axes of Canonical Correspondence Analysis (CCA). Electrical conductivity and water temperature (P = 0.002) were the most influential variables on species. There was a significant negative correlation of seven species to conductivity. Of those (F. cf. japonica and C. vidua) showed a significant positive correlation to water temperature, while C. candida was negatively correlated to water temperature (P

BİRECİK BARAJ GÖLÜ HAVZASI (ŞANLIURFA) VE HAZAR GÖLÜ(ELAZIĞ) OSTRACODLARI (CRUSTACEA)HAKKINDA ÖN ÇALIŞMA

In this study, the samples which collected from The Birecik Reservoir Basin and Lake Hazar were examined. As a result, 11 species from Birecik Reservoir Basin (Darwinula stevensoni (Brady &amp; Robertson,1870); Candona neglecta Sars, 1887; Candona angulata Müller, 1900; Fabaeformiscandona sp.; Pseudocandona cf albicans; Cryptocandona sp.; Ilyocypris sp.; Heterocypris salina (Brady, 1868); Potamocypris sp.; Limnocythere inopinata (Baird,1843); Kovalevskiella sp.) and 3 species from Lake Hazar (Candona neglecta Sars, 1887; Candona sp.; Limnocythere inopinata (Baird, 1843)) were found. All of these species are new records for The Birecik Reservoir Basin and Lake Hazar

Distribution and ecology of Ostracoda (Crustacea) from troughs in Turkey

Troughs are artificially transformed natural springs, underground waters, or related habitats. Some effects of such transformation are mentioned in a few studies, but there has been no extensive study on species composition and diversity in troughs. To contribute to the knowledge on the ostracods in troughs, we examined ostracod composition and diversity in 105 troughs from 6 provinces (Bolu, Erzincan, Gaziantep, Kahramanmaraş, Ordu, Van) in Turkey. The troughs were randomly visited between the years 2006 and 2010. A total of 32 ostracod species and a mean number of 2.16 species per trough were found. The most common 4 species (Heterocypris incongruens, Ilyocypris bradyi, Psychrodromus olivaceus, Candona neglecta) occurred in 57, 48, 34, and 26 different troughs, respectively. A UPGMA dendrogram displayed these 4 species in the same clustering group. The first 2 axes of canonical correspondence analysis explained about 69.5% of the variations in the species data set between 15 species and 5 environmental variables. The 2 most important explanatory variables, altitude (P = 0.008, F = 2.389) and redox potential (P = 0.034, F = 2.230), were the 2 most effective factors on species occurrence in these troughs. Ecological tolerance and optimum estimates of cosmopolitan species were generally higher than the mean values. The Shannon-Wiener index showed high values for the 4 most common species, supporting the effect of their dominance. Our results suggest that troughs can have relatively high ostracod richness but evenness can be low due to the strong dominance of one or more species.

Retrospective evaluation of 104 tinea capitis cases

Troughs are artificially transformed natural springs, underground waters, or related habitats. Some effects of such transformation are mentioned in a few studies, but there has been no extensive study on species composition and diversity in troughs. To contribute to the knowledge on the ostracods in troughs, we examined ostracod composition and diversity in 105 troughs from 6 provinces (Bolu, Erzincan, Gaziantep, Kahramanmaras, Ordu, Van) in Turkey. The troughs were randomly visited between the years 2006 and 2010. A total of 32 ostracod species and a mean number of 2.16 species per trough were found. The most common 4 species (Heterocypris incongruens, Ilyocypris bradyi, Psychrodromus olivaceus, Candona neglecta) occurred in 57, 48, 34, and 26 different troughs, respectively. A UPGMA dendrogram displayed these 4 species in the same clustering group. The first 2 axes of canonical correspondence analysis explained about 69.5% of the variations in the species data set between 15 species and 5 environmental variables. The 2 most important explanatory variables, altitude (P = 0.008, F = 2.389) and redox potential (P = 0.034, F = 2.230), were the 2 most effective factors on species occurrence in these troughs. Ecological tolerance and optimum estimates of cosmopolitan species were generally higher than the mean values. The Shannon-Wiener index showed high values for the 4 most common species, supporting the effect of their dominance. Our results suggest that troughs can have relatively high ostracod richness but evenness can be low due to the strong dominance of one or more species.