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94. Phylogenetic position of the Ohiya rat (Srilankamys ohiensis) based on mitochondrial and nuclear gene sequence analysisElena Bužan, Marie Pagès, Johan Michaux, Boris Kryštufek, 2011, original scientific article Abstract: We investigated the phylogenetic position the Ohiya rat, endemic to Sri Lanka, Srilankamys (Rodentia, Murinae), within the tribe Rattini based on the combined analysis of three independent genes (a mitochondrial one and two nuclear exons). Three major lineages (the Maxomys, the Dacnomys and the Rattus divisions) were retrieved as monophyletic groups within the tribe Rattini. Srilankamys was not affiliated to any of the representatives of the Dacnomys division as it was supposed based on morphological characters, but clearly appeared as the first genus to diverge among the Rattus division. The Mindanao Shrew Mouse, Crunomys melanius, emerged as a part of the Maxomys division raising questions about the validity of the Crunomys and the Maxomys divisions as currently defined. Molecular date of divergence between Srilankamys and the other representatives of the Rattus division falls within the interval 6.7 +- 0.74 Mya, coinciding with the time of the isolation of Sri Lanka from the Deccan peninsula and the aridification period owing to the climate change at the end of the Miocene epoch. We suggest that the isolation of Sri Lanka from the continent, reinforced by the action of a seasonal monsoon-dominated climate, would have led to the isolation of some ancestral rodents of the Rattus division, which would have differentiated later into the Ohiya rat by a vicariant process. In a more general point of view, our study supports the previous results obtained on other organisms and evidence that Sri Lanka appears to be characterized by a particular fauna as compared to the Indian mainland. This island would therefore be considered as a specific distinct hotspot of biodiversity
Keywords: Ohiya rat, Srilankamys ohiensis, rodents, Phylogenetic analyses
Published in RUP: 15.10.2013; Views: 3767; Downloads: 140
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95. New insights into the taxonomy and phylogeny of social voles inferred from mitochondrial cytochrome b sequencesBoris Kryštufek, Tanya Zorenko, Elena Bužan, 2012, original scientific article Abstract: We sequenced the entire cytochrome b gene in Microtus paradoxus from Turkmenistan and Microtus socialis from Crimea and Kalmykia. Phylogenetic relationships among social voles were reconstructed by the inclusion into analyses of a further 23 published haplotypes belonging to six species. The two probabilistic methods which were used in phylogenetic analyses, the Bayesian inference and Maximum Likelihood, yielded very similar results. Both trees showed two highly divergent lineages which were further subdivided into seven species. The socialis lineage encompassed four species (M. socialis, M. irani, M. anatolicus, and M. paradoxus), and the remaining three species clustered into the guentheri lineage (M. guentheri, M. hartingi, M. dogramacii). The ranges for nucleotide divergences between seven species of social voles (4.95-9.28% and 4.18-8.81% for mean and net divergences, respectively) mainly exceeded 4.3%, which is frequently regarded as the conservative cut-off between sibling species in the specious genus Microtus
Keywords: Microtus socialis, Microtus paradoxus, Arvicolinae, Cryptic species, Species delimitation, Molecular systematics
Published in RUP: 15.10.2013; Views: 3404; Downloads: 129
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96. Mitochondrial cytochrome b sequences resolve the taxonomy of field mice (Apodemus) in the western Balkan refugiumBoris Kryštufek, Martina Lužnik, Elena Bužan, 2012, original scientific article Abstract: Apodemus sylvaticus stankovici, described from the topographically rough landscape of the western Balkan glacial refugium, was recently proposed as being either a junior synonym of Apodemus flavicollis or a species on its own right. To untangle this taxonomic vagueness, we sequenced complete cytochrome b gene in 28 field mice collected at 12 locations in the mountains of Bosnia and Herzegovina, Montenegro, western Macedonia and northern Greece. Samples yielded 27 new haplotypes which clustered into two distinct groups. One of these clades also included the reference haplotype of A. flavicollis, while another cluster emerged as being identical with the reference sample for A. sylvaticus. As is common in Apodemus, both species retrieved in our analysis were characterized by low levels of intraspecific variation (0.4- 0.9%) as opposed to a high level of differentiation between them (8.0-10.0%); therefore, the taxonomic classification of our material was without doubt. We found no evidence regarding the presence of an additional cryptic species in the mountains of the western Balkans. The very similar values of genetic variability in the two species imply their common evolutionary history of a long-term coexistence in the western Balkan refugium
Keywords: Mice, Apodemus flavicollis, Apodemus sylvaticus, Apodemus stankovici, molecular taxonomy
Published in RUP: 15.10.2013; Views: 4493; Downloads: 93
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