An updated checklist of Recent ostracods (Crustacea: Ostracoda) from inland waters of Sicily and adjacent small islands with notes on their distribution and ecology

The Inland Water Copepod Fauna of a Traditional Rural Landscape in a Mediterranean Island (Crustacea, Copepoda)

Although the Mediterranean area is a well-known hotspot of biological diversity, the crustacean assemblages inhabiting inland waters of the Mediterranean islands are to date unevenly known, and detailed information is missing for most taxa and areas. In the frame of this paper, we provide a checklist and a characterization of the copepod fauna of the lentic water bodies occurring in a traditional rural landscape of Sicily, where the co-existence of agriculture, woodlands, and pastoral activities lead to the presence of a wide range of different aquatic habitats. Overall, 22 copepod species belonging to the orders Calanoida, Cyclopoida, and Harpacticoida have been found in the 92 surveyed sites, stressing the conservation value of the area. In the study area, species widespread in the west Palaearctic region co-exist with strictly Mediterranean elements and a small but biogeographically significant group of species with northern or Balkan affinities, which support the role of the investigated area as a refugium for species that colonised Sicily during Pleistocene climate fluctuations and are now restricted to the more wet parts of the island. A single non-native species has been found, and its distribution is currently limited to permanent, man-made reservoirs.

A reassessment of the origin and distribution of the subterranean genus Pseudolimnocythere Klie, 1938 (Ostracoda, Loxoconchidae), with description of two new species from Italy

Groundwater ecosystems host a rich and unique, but still largely unexplored and undescribed, biodiversity. Several lineages of ostracod crustaceans have subterranean representatives or are exclusively living in groundwaters. The stygobitic genus Pseudolimnocythere Klie, 1938 has a West Palearctic distribution, and includes few living and fossil species of marine origin. Through a comprehensive literature review and the description of the two new living species, Pseudolimnocythere abditasp. nov. and Pseudolimnocythere sofiaesp. nov., from springs in the Northern Apennines, Italy, a morphological analysis was carried out with the aim of comparing the valve morphology of living and fossil species, and to discuss previous hypotheses about time and mode of colonization of inland waters. Pseudolimnocythere species show a low variability in valve morphology, with a remarkable stasis over geological times. The distribution of extant and fossil species is consistent with a scenario of multiple and independent events of colonization of continental habitats linked to sea level variations starting from Middle Miocene in the Paratethys and, later, in the Mediterranean. The most common colonization routes of inland waters have taken place through karst formations along ancient coastlines, although we cannot exclude some minor active migration through the hyporheic zone of streams. Available distribution data suggest a poor dispersal ability of Pseudolimnocythere species after they had colonized continental waters.

Diversity and Distribution of the Inland Water Decapods of Sicily (Crustacea, Malacostraca)

The current knowledge of Sicilian inland water decapod malacostracans is scarce and an updated synopsis on species distribution is lacking. Therefore, we reviewed the checklist and recent distribution of Sicilian inland water decapods based on published and unpublished records and novel observations with the aim of providing an exhaustive repository, also to be used as a sound baseline for future surveys. Overall, five native decapod species occur in the study area, i.e., the atyid shrimp Atyaephyra desmarestii, the palaemonid shrimps Palaemon adspersus, P. antennarius, and P. elegans, and the freshwater crab Potamon fluviatile, and their current local distributions are described. In addition, three alien species were recorded: the common yabby Cherax destructor and the red swamp crayfish Procambarus clarkii, strictly linked to inland waters, and the Atlantic blue crab Callinectes sapidus, a mainly marine species that can also colonise the lower stretches of rivers and coastal brackish waters. The collected data suggest the existence of a partial segregation of native versus non-native species, with the latter currently confined to coastal water bodies and the lower stretches of rivers. Moreover, the exclusively freshwater caridean A. desmarestii and P. antennarius show a parapatric distribution in the study area, which may suggest the existence of mutual exclusion phenomena. The results obtained raise some concerns about the effects of alien species on the native biota, and dedicated monitoring and management strategies should be implemented in order to better understand and mitigate their impact.

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.