Nivicolous myxomycete assemblages were surveyed on the northwest of the Greater Caucasian ridge in May-June 2010 and 2011 at a north facing transect between 1,700 and 2,920 m elevation of the summit Malaya Khatipara situated within the Teberda State Biosphere Reserve. Morphological characters of 396 collections representing 45 taxa (39 species, 3 varieties, and 3 forms) of myxomycetes in 8 genera and 5 families were recorded. Many (13) taxa are classified as rare (a species represents <0.5 % of all records). Only seven species were found to be widely distributed (present in 50 % or more of the 17 studied localities). To confirm the assignment of specimens to morphospecies, we obtained independently from determination 145 partial sequences of the 18S SSU rRNA gene from 35 taxa of Lamproderma, Meriderma, Physarum and Diderma, which turned out to represent 58 genotypes. Most of the taxa represented by more than one sequence had several genotypes, with an average of 1.7 genotypes per taxon. Except for three taxonomically difficult groups of species, partial SSU sequences did well correspond with the respective morphospecies and where similar or identical to sequences of specimens from the European Alps, making this marker a good candidate for barcoding in myxomycetes. Species richness and diversity increased from subalpine crooked-stem birch forests (23 species, 2 varieties, H′02.8, E00.88, D00.08) to alpine dwarf shrub communities (34 species and 2 varieties, 2 forms, H′03.2, E00.89, D0 0.05) but decreased again for alpine meadows (27 species and 2 varieties, 2 forms, H′03.1, E00.91, D00.06). Species richness and alpha-diversity reached maximum values for ground litter, whereas leaves and stems of living shrubs above ground harboured a more depauperate myxomycete assemblage.
Background: Here, for the first time, we report a barcoding survey of the dipterian family Ulidiidae (with two subfamilies Ulidiinae and Otitinae) coupled with morphology. To date, this is the first comprehensive analysis of the family that relies on molecular data. To reconstruct probable higher-level phylogenetic relationships between the genera of Ulidiidae, we exploited maximum likelihood and Bayesian inference, and additionally, we utilized a modern Markov model of codon substitutions for protein-coding genes coupled with the maximum likelihood approach to establish more realistic evolutionary scenarios connecting Ulidiinae and Otitinae. Results: Though we found morphological synapomorphic characters that clearly distinguish two groups of genera, formerly relating to two subfamilies, the monophyly of the clade Otitinae was not firmly supported by molecular phylogenetic reconstructions. The subfamily Ulidiinae was recovered as the basal likely paraphyletic group with high reliability. Overall, our results suggest the inclusion of the genera Homalocephala and Seioptera into the tribe Seiopterini (Otitinae). Three genera of Ulidiinae (Physiphora, Timia, Ulidia), eight genera of Otitinae (Ceroxys, Herina, Melieria, Myennis, Otites, Pseudotephritis, Seioptera, Tetanops), and the genus of Homalocephala with still unconfirmed systematic status were included in the analysis.
A new widespread myxomycete species, Physarum pseudonotabile, inhabiting the arid regions of the Eurasia, South and North America is described and illustrated. Tentatively assigned to Ph. notabile T. Macbr., a phylogeny based on the small ribosomal subunit (SSU) and elongation factor 1 alpha (EF1a) genes placed the new species in a clade far from Ph. notabile. Ph. pseudonotabile was found to be frequent in surveys based on the moist chamber culture technique with samples of litter, bark and herbivore dung collected in dry steppe and deserts of the Caspian lowland (Russia), Kazakhstan, Mongolia, China, Spain, Argentina and USA. The main morphological difference between Ph. pseudonotabile and Ph. notabile lies in spore ornamentation. Spores of the former species display irregularly distributed verrucae, whereas the latter species possesses spores with dense and regularly arranged spinulae. In addition, the ecological preferences of the two species differ. Ph. pseudonotabile inhabits the bark of living plants and ground litter in arid regions, whereas Ph. notabile is found on coarse woody debris in boreal and temperate forests. Although the new species appears to be closest to Ph. notabile morphologically, the phylogenetic analysis reveals Ph. pusillum and Ph. nivale as the closest relatives. In addition, the molecular investigations revealed a considerable amount of hidden diversity within species of Physarum with gray lime flakes. Currently we have only sufficient material to assess the morphological variation of Ph. pseudonotabile but expect that more taxa within this clade may emerge within studies combining morphological and molecular analyses.
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