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In this contribution, we aim at determining the role of climate in shaping the current and historical (Last Glacial Maximum and Middle Holocene) distributions of two parapatric bat species (Myotis daubentonii and Myotis capaccinii) in Europe, using ensemble Habitat Suitability Modelling (HSM). Model projection to current climatic conditions predicted distributions largely coherent with the ones observed for the two species in the study area. Temperature- and precipitation-linked variables well accounted for the observed parapatry of the two target species. Moreover, areas of co-occurrence turned out to be those where the main ecological needs concerning the most important range-limiting variables are met for both species. Model projections to past scenarios allowed us to hypothesize the effects of climatic oscillations over the distribution of the two species during the Late Pleistocene and Holocene. Extreme range contractions during the Last Glacial Maximum and the subsequent expansions during Middle Holocene were predicted, consistently with general patterns of post-glacial recolonization routes of many temperate bat species in Europe. Our findings are largely coherent with recent phylogeographic studies investigating the two target species, thus corroborating the validity of potential distribution scenarios obtained from the models and, more importantly, confirming the great influence that glacial cycles had in shaping the biogeography of the European fauna. [ABSTRACT FROM AUTHOR]

Based on information from ITS (112 specimens) and the chloroplast markers trnL-trnF and rpl16 (116), this study reconstructs the phylogeography of the moss Sanionia uncinata, with a focus on Europe. In a global context, especially ITS data, suggest a scenario with a major split, between one southern hemisphere and one eastern Asiatic lineage. Descendants of the first dispersed back to the northern hemisphere where they are presently widespread, and those of the second lineage likewise spread over much of the north. Within the latter, a separate group evolved which is the only one present in central Europe and has not reached arctic Europe. Members of this group also colonized tropical Africa. In addition, members of the two main lineages most likely survived the last glaciation in the north or north-east, whereas representatives of the last evolved group could have survived the glacial period in southern Europe. The results underline potential problems with too small data sets in phylogeographic studies. European ITS data suggest two cryptic species, but the global sampling includes representatives of several of the haplotypes that are 'missing' in Europe, and the chloroplast data suggest partly different groups than ITS. [ABSTRACT FROM AUTHOR]

Knowing the origin of invasive taxa, whether multiple introductions have occurred, and levels of genetic variation relative to the native range, is vital to conducting rigorous tests of hypotheses to explain biological invasions. We explore phylogeographical relationships of two Eurasian knapweed taxa that are invasive in North America, Centaurea diffusa and C. stoebe micranthos (Asteraceae), using chloroplast DNA intron sequences. We also gathered data from C. stoebe stoebe, hybrids between C. diffusa and C. stoebe stoebe ( C. x psammogena), and three other species in the genus. We sequenced 213 individuals from Eurasia and North America, and found 22 haplotypes. Centaurea diffusa has lower haplotype diversity and allelic richness in the introduced range relative to the native range. Even with reduced variation, the data suggest at least two introductions of C. diffusa. There is a trend towards reduced variation in C. stoebe micranthos, but it is not significant. One of the haplotypes found in North American C. stoebe micranthos matches a haplotype from a taxon other than C. stoebe micranthos in Europe. This suggests introgression of the chloroplast between taxa, or possibly the invasion of another Centaurea taxon into North America. Additionally, C. diffusa, C. stoebe micranthos, and C. stoebe stoebe share several haplotypes, including their most common haplotype. This suggests ongoing hybridization between the species or incomplete segregation. These data can guide further exploration for the origins of these species, and point out locations within the introduced range with unique and diverse genetic makeup. [ABSTRACT FROM AUTHOR]

DNA barcodes are widely used for species identification and biogeographic studies. Here, we compare the use of full mitochondrial genomes versus DNA barcodes and other mitochondrial DNA fragments for biogeographic and ecological analyses. Our dataset comprised 120 mitochondrial genomes from the genus Clunio (Diptera: Chironomidae), comprising five populations from two closely related species ( Clunio marinus and Clunio balticus ) and three ecotypes. We extracted cytochrome oxidase c subunit I (COI) barcodes and partitioned the mitochondrial genomes into non-overlapping windows of 750 or 1500 bp. Haplotype networks and diversity indices were compared for these windows and full mitochondrial genomes (15.4 kb). Full mitochondrial genomes indicate complete geographic isolation between populations, but do not allow for conclusions on the separation of ecotypes or species. COI barcodes have comparatively few polymorphisms, ideal for species identification, but do not resolve geographic isolation. Many of the similarly sized 750 bp windows have higher nucleotide and haplotype diversity than COI barcodes, but still do not resolve biogeography. Only when increasing the window size to 1500 bp, two windows resolve biogeography reasonably well. Our results suggest that the design and use of DNA barcodes in biogeographic studies must be carefully evaluated for each investigated species.

Intraspecific diversity in parasites with heteroxenous life cycles is guided by reproduction mode, host vagility and dispersal, transmission features and many other factors. Studies of these factors in Digenea have highlighted several important patterns. However, little is known about intraspecific variation for digeneans in the marine Arctic ecosystems. Here we analyse an extended dataset of partial cox1 and nadh1 sequences for Tristriata anatis (Notocotylidae) and confirm the preliminary findings on its distribution across Eurasia. Haplotypes are not shared between Europe and the North Pacific, suggesting a lack of current connection between these populations. Periwinkle distribution and anatid migration routes are consistent with such a structure of haplotype network. The North Pacific population appears ancestral, with later expansion of T. anatis to the North Atlantic. Here the parasite circulates widely, but the direction of haplotype transfer from the north-east to the south-west is more likely than the opposite. In the eastern Barents Sea, the local transmission hotspot is favoured.

Melting snowfields in polar and alpine regions often exhibit a red and orange colouration caused by microalgae. The diversity of these organisms is still poorly understood. We applied a polyphasic approach using three molecular markers and light and electron microscopy to investigate spherical cysts sampled from alpine mountains in Europe, North America and South America as well as from both polar regions. Molecular analyses revealed the presence of a single independent lineage within the Chlamydomonadales. The genus Sanguina is described, with Sanguina nivaloides as its type. It is distinguishable from other red cysts forming alga by the number of cell wall layers, cell size, cell surface morphology and habitat preference. Sanguina nivaloides is a diverse species containing a total of 18 haplotypes according to nuclear ribosomal DNA internal transcribed spacer 2, with low nucleotide divergence (≤3.5%). Based on molecular data we demonstrate that it has a cosmopolitan distribution with an absence of geographical structuring, indicating an effective dispersal strategy with the cysts being transported all around the globe, including trans-equatorially. Additionally, Sanguina aurantia is described, with small spherical orange cysts often clustered by means of mucilaginous sheaths, and causing orange blooms in snow in subarctic and Arctic regions., (© FEMS 2019.)