Water chemistry and not urbanization influences community structure of non-marine Ostracoda (Crustacea) in northern Belgium

Urbanization is one of the major causes of the destruction of natural habitats in the world. Cities are urban heat islands and can thus significantly influence populations of plants and animals. The research project SPEEDY investigated the effects of urbanization in northern Belgium with a nested sampling design at local and landscape scales for a variety of organisms. Here, we tested the effects of urbanization on non-marine ostracod communities, sampling 81 small pools in three urbanization categories, as defined by percentage built up cover (low, intermediate, high). We identified 17 ostracod species, together occurring in 60 of the 81 sampled pools. We found that urbanization per se had no significant effect on ostracod communities. Of all the measured local factors, ammonium and total phosphorus concentrations had a significant effect on the community structure. In contrast, water temperature had no significant effect, most likely because the ostracod species found in northern Belgium in the present survey mostly have wide temperature tolerances.

Comparison of Ostracoda (Crustacea) species composition between lakes and streams at high elevations in Turkey

Ostracods are one of the most suitable organisms because of their ecological and morphological preferences for habitat types to study the diversity between streams and lakes. Here, 24 streams and 16 lakes were sampled in 2019 to evaluate the species compositions between streams and lakes. Environmental heterogeneity in the sense of the physico-chemical variables was found among the habitats. 24 of the 29 species with 923 individuals were found in the lakes when 13 species with 898 individuals were found in the streams. Eight species were common in both habitat types. Species contributing about 70.81% to the significant differences in the species composition between the habitats showed cosmopolitan characteristics. Species variation among the replicates of lakes were higher than streams. Results indicated that the species composition was probably associated to dissolved oxygen in lakes, while electrical conductivity in streams. Relationship amid elevational range and ostracod species richness was negative in lakes when there was no clear relationship in the streams. Overall, results suggested that determination of influential regional factors in different aquatic bodies can provide important contributions to the estimation of which habitat types can be chosen by species, and the using of species as bioindicators.

Hyporheic ostracods (Crustacea, Ostracoda) from Texas (USA) with six new species

Between 2015 and 2017, 58 ostracod taxa were collected at 30 locations in 111 samples from the hyporheic zone of surface streams in Texas, U.S.A. Six new species (Bradleycypris foresteri n. sp., Bradleystrandesia macula n. sp., Pseudocandona lordi n. sp., Indocandona rusti n. sp., Stenocypris sancari n. sp., Cyclocypris dalyana n. sp.) are described based on carapace and soft body parts. Additionally, 17 species and two genera (Vestalenula and Indocandona) are presented as new records for Texas, and Indocandona rusti n. sp. is the first record of the genus outside India. Taxonomic positions of the new species are discussed along with ecological information. One-hundred and six nonmarine ostracod species are now reported from Texas. However, ongoing studies suggest that actual species richness is much higher.

Modern brackish bryostromatolites (“bryoliths”) from Zeeland (Netherlands)

Bryostromatolites are found in stressed environments from the Paleozoic to the Recent. They are formed by alternating layers of bryozoans and microbes. This study investigates recent bryostromatolites in brackish ponds in the Netherlands to better understand ancient analogues and the environments which hosted them. They formed a fringing reef at the site Ronde Weel and a barrier reef at Kaaskenswater. The ponds had low biodiversity with only one bivalve species, two gastropod species, one ostracod species, and three diatom species comprising most of the easily fossilizable taxa; one isopod species, one decapod species, and two polychaete species were also present. Observations of microbial layers and cementation practices indicate that an alternation of bryozoan-favouring conditions and microbe-favouring conditions is essential to forming bryostromatolites. The collected bryostromatolites only had tiny living bryozoan patches. Water tests confirmed a brackish environment but with enriched arsenic and titanium concentrations and periodic euxinia. The extreme environment explains the lack of biodiversity and may provide information about the environments in which past bryostromatolites formed.

New records of ostracods and ammonites from the Aalenian (mainly Concavum Zone) of the Zollernalb (Swabian Alb, SW Germany)

The lithostratigraphy and ammonite/ostracod biostratigraphy and the accompanying fauna of several sections and outcrops around the Hohenzollern (Zollernalb, SW Germany), ranging from the topmost Opalinuston Formation (uppermost Lower Aalenian) to the basal Wedelsandstein Formation (lowermost Lower Bajocian) are described and analyzed. The study of ostracods from 41 samples from the Aalenian and Lower Bajocian of the Heiligenbach, Hausterberg and Roschbach sections has yielded approximately 4,100 specimens. Significant changes in the ostracod assemblage occur at the base of the Lower Aalenian “Comptum” Subzone, at the Bradfordensis/Gigantea subzonal boundary, at the Bradfordensis/Concavum zonal boundary and at the Aalenian/Bajocian boundary (Concavum/Discites zones). A minor change occurs above the Calceola-Bank within the Concavum Zone. The following new ostracod species are described: Cytheropterina crassicostatasp. nov., Eucytherura ebertisp. nov. and Eucytherura foveolatasp. nov. In addition, 15 presumably new species are briefly described; 10 ‘incertae sedis’ taxa are figured, but left in open nomenclature. The ammonite faunas of the Inopernabank and Konglomeratbank beds (Upper Aalenian, Bradfordensis Zone, Gigantea Subzone) as well as the ammonite faunas from the Calceolabank and Rostrote Kalkbank beds (Upper Aalenian, Concavum Zone, Concavum Subzone, cavatum biohorizon) are described and correlated with those of other areas.

On some modern Ostracoda (Crustacea) from the Tibetan Plateau in SW China, with descriptions of three new species

Studies of Holocene ostracods of the Tibetan Plateau have mostly centred around valves and carapaces collected from lake sediments, some at or near the substrate surface and others from short cores. Reports from habitats other than lakes are scarce, and few living species found in this region have appendages described, hindering further taxonomic and phylogenetic work. For this study collections of living ostracods were made in mostly ponds, as well as two rivers and one lake. Six species, including three previously undescribed, were recovered: Tonnacypris estonica (Järvekülg, 1960), Arctocypris edita n. sp., Cypris pubera O.F. Müller, 1776, Potamocypris variegata (Brady & Norman, 1889), Ilyocypris tibeta n. sp., and Fabaeformiscandona monticulus n. sp. Specimens of Tonnacypris estonica include males, previously unknown for this species, and suggesting it is a geographical parthenogen. A revision of the fifth limb morphology of the genus Arctocypris, and a subsequent amended diagnosis of the genus are given. Based on carapace and appendage features, Eucypris mareotica (Fischer, 1855) is transferred to this genus: Arctocypris mareotica (Fischer, 1855) com. nov. There are now ca. 100 ostracod species reported from modern or subsurface sediments on the Tibetan Plateau, but only 19 of those can be confirmed as alive when collected (i.e. had appendages intact). The families Limnocytheridae and Ilyocyprididae are both relatively diverse on the plateau compared with the Palaearctic zoogeographical region generally. About one third of ostracod species reported from the Tibetan Plateau are only known from there, suggesting a potentially very high rate of endemism.

Diversity analyses of nonmarine ostracods (Crustacea, Ostracoda) in streams and lakes in Turkey

In order to compare species compositions of ostracods, 25 streams and 15 lakes were sampled in the spring, summer, and autumn seasons of 2018. A total of 26 ostracod species were found in lakes (18 spp.) and streams (12 spp.). The Shannon index (H’) and evenness values of streams were higher than in lakes in all seasons. The highest H’ values for all combined (lakes + streams) and lake data were reported in the autumn season, and in spring the highest values were in streams. According to the β-diversity (β) index values, the variability of ostracod species composition in lakes was higher than in streams, and its value was highest in spring (0.40) and lowest in summer (0.34) among all seasons for combined data. Pairwise comparison of spring and autumn displayed higher β-diversity values than other comparisons, while its value was 0.41 between lakes and streams. According to canonical correspondence analysis results, elevation had a significant (P = 0.006) effect on distribution of species. All results suggested the importance of seasonality for evaluating the biodiversity of a region rather than the number of sampling sites, and the autumn season seems to be richer than other seasons in terms of species diversity.

Freshwater ostracods (Crustacea) from Hainan Island, southern China, with description of a new species

In this study, 24 non-marine ostracod species were found in 142 samples collected from diverse water bodies from Hainan Island, south China. Among them, a new species Pseudocypretta lineata n. sp. is described and illustrated. Twelve species are new records for China. Among them, six species are identified: Microdarwinula zimmeri (Menzel, 1916), Pseudocypretta lineata n. sp., Pseudostrandesia mamarilorum (Victor & Fernando, 1981c), Stenocypris malayica Victor & Fernando, 1981b, Stenocypris orientalis Victor & Fernando, 1981b and Strandesia freyi Victor & Fernando, 1981c. Six species are left in open nomenclature: Batucypretta sp., Candonopsis? sp., Cypridoidea gen. et sp. indet. 1, Cypridoidea gen. et sp. indet. 2, Cyprinotus cf. kimberleyensis McKenzie, 1966 and Vestalenula sp. Additionally, a re-description of Strandesia freyi is provided.