Decline of unique Pontocaspian biodiversity in the Black Sea Basin: a review

Environmental Biolog

TAXONOMIC STATUS OF LAELAPS PETRISCHEVAE ZEMSKAYA ET LANGE, 1979 (ACARI: PARASITIFORMES: GAMASINA)

Laelaps petrischevae Zemskaya et Lange, 1979 was described ex Microtus voles from the northern parts of Western and Middle Siberia. However, the species has not been mentioned later in taxonomic and faunistic papers dealing with the ectoparasitic gamasid mites of Siberia. Examination of newly collected laelapid mites from the Yamal Peninsula as well as the comparison with the published data led to conclusion that L. petrischevae Zemskaya et Lange, 1979 (syn. n.) is a junior synonym of L. alaskensis Grant, 1947. Key for identification of females of the Laelaps species inhabiting the northern regions of Western and Middle Siberia is given

Phylum Mollusca

[Introduction] Two classes of molluscs occur in Palaearctic freshwater habitats: Gastropoda and Bivalvia. Molluscs are present in most Palaearctic freshwater habitats. Frequently terrestrial snails fall into aquatic habitats, and care should be taken not to confuse them with aquatic taxa. Many taxa are protected by local and regional conservation and/or fishing laws, and several invasive species have been reported in Palaearctic waters. Freshwater mollusc identification is primarily based on shell morphology. However, shell shape can be modified substantially by water currents, available minerals, and predatory pressures (summarized in Rogers & Wethington, 2007). Consequently, we recommend that identifications be based on a series of specimens when possible.[Limitations] Freshwater mollusc identification is primarily based on shell morphology. However, shell shape can be modified substantially by water currents, available minerals, and predatory pressures (summarized in Rogers & Wethington, 2007). Consequently, we recommend that identifications be based on a series of specimens when possible.[Material preparation and preservation] Empty shells should be gently cleaned using ethyl alcohol and water. Shells can be air dried. Whole animals and soft-tissue samples should be preserved according to the recommendations described below for each class

Intraspecific morphological and genetic variability in the European freshwater snail Radix labiata (Rossmaessler, 1835) (Gastropoda: Basommatophora: Lymnaeidae)

Radix labiata is a widely distributed Palaearctic freshwater snail. This work aims to improve the knowledge of the intraspecific variability in the most important characters used for its determination. To find out which characters are really suitable to distinguish this species from other similar Radix species an integrative approach was applied, involving morphological and molecular data.Molecular sequences of the nuclear spacer fragment ITS-2 and/or the mitochondrial gene fragment cyt-b were obtained from 26 individuals of R. labiata from different regions of Europe, including type localities of Limnaeus pereger labiatus. From the subsample of 24 specimens of which sequences of both gene fragments were available, the variability of several characters that are commonly used for species identification (shell morphology, mantle pigmentation, shape and position of the bursa copulatrix, length and position of the bursa duct, length ratio of praeputium to penial sheath) were measured or documented. Morphological characters distinguishing R. labiata from R. balthica, R. lagotis and the genus Stagnicola are discussed. The best morphological character to differentiate these species is the position of the bursa and the bursa duct. Mantle pigmentation and the ratio of the length of the praeputium to that of the penial sheath are not useful for differentiating R. labiata and R. balthica. Analysis of the network of haplotypes (cyt-b) revealed no correlation between recognisable clusters and geography amongst the studied specimens

Male hosts drive infracommunity structure of ectoparasites

We studied the co-occurrence of flea species in infracommunities of 16 rodents from four regions (South Africa, Tanzania, central Europe and western Siberia) using null models, and predicted that flea co-occurrences will be expressed more strongly in male than in female hosts. We examined patterns of co-occurrence (measured as the C score) in infracommunities of fleas that are parasitic on male and female hosts by comparing co-occurrence frequencies with those expected by chance. When a significant degree of nonrandomness in flea co-occurrences was detected, it indicated aggregative infracommunity structure. In Tanzanian rodents, no significant flea co-occurrences were detected in either male or female hosts. In a South African rodent, significant flea co-occurrences were not detected in males, but were found in females in some localities. In Palaearctic rodents, significant nonrandomness was detected either equally for males and females or more frequently in males than in females. Meta-analyses demonstrated that the frequency of the detection of nonrandomness in flea co-occurrences was significantly higher in male than in female hosts. The values of the standardized effect size (SES) for the C score differed significantly among host species, but not between host genders. When the Palaearctic hosts were analyzed separately, the effects of both host gender and species appeared to be significant, with the SES values for the C score in males being smaller than those in females. The strength of the gender difference in the manifestation of flea community structure increased with increasing gender difference in flea species richness, and with decreasing gender difference in flea prevalence for the Palaearctic hosts. We conclude that male hosts are the main drivers of flea infracommunity structure. However, the manifestation of gender bias in flea community structure varies among host species, and is likely determined by the pattern of species-specific spatial behavior. © 2011 Springer-Verlag.Articl

The first freshwater molluscs from Wrangel Island, Arctic Russia

The first finding of a freshwater snail, Sibirenauta sibiricus (Westerlund, 1877), in one of the lakes on Wrangel Island (north-eastern Russia) is reported. No freshwater mollusc species have hitherto been known from this island. Specimens from the island are morphologically compared with the type series of the species. How aquatic molluscs may have migrated to the Arctic island is briefly discussed