Mole rats (genus Nannospalax) display prolific chromosomal variation with more than 50 distinct cytotypes. These cytotypes are largely indistinguishable morphologically, are mainly allopatric and their taxonomic ranking is contradictory. We established a cytochrome b phylogeny for 15 cytotypes belonging to all three species recognized on morphological grounds (morphospecies): N. leucodon, N. xanthodon and N. ehrenbergi. Phylogenetic reconstructions yielded two highly divergent groups which are in agreement with the current division into two subgenera (Nannospalax and Mesospalax). The former comprised samples from south-eastern Turkey, Israel and Egypt (the morphospecies N. ehrenbergi). Basal dichotomy within Mesospalax remained unresolved and the putative sister position of N. leucodon against the two lineages of N. xanthodon was not supported in our analysis. Net divergences between sister cytotypes were low (( 2.0%) and two N. leucodon cytotypes were not even reciprocally monophyletic. Among the three morphospecies, the genetic diversity was lowest in N. leucodon (2.4% ± 0.3%), highest in N. xanthodon (8.8% ± 0.7%) and intermediate in N. ehrenbergi (5.0% ± 0.5%). Our results show that associations between genetic and chromosomal variation are not widespread and common in mole rats, and therefore refute the generalization of a ‘cytotype-equals-species’ approach.
COBISS.SI-ID: 2117075
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
COBISS.SI-ID: 2081491
In the cave crickets Troglophilus cavicola and T. neglectus, we analyzed the contents and morphology of lipid droplets, glycogen rosettes and protein granula at the beginning, the middle and the end of overwintering applying optic, TEM and biochemical methods. T. cavicola use glycogen continuously, and stop using lipids in the middle of overwintering, while this is inverse in T. neglectus. Till the middle of overwintering, all individuals exploit proteins. We found that the fat body is differently engaged in metabolism of both cave crickets during overwintering, supporting a more glycogen dependant metabolism in T. cavicola, and a more lipid dependant one in T. neglectus.
COBISS.SI-ID: 18020104