RESUMO
BACKGROUND: There are two species of Mus in the Caucasus: M. musculus and M. macedonicus. M. musculus is widespread in the Caucasus, where the species is found everywhere from the Black to the Caspian Sea. M. macedonicus is ubiquitous Transcaucasia. The most north-astern border of its distribution in the Caucasus, according to the literature, is located in the Derbent region, near the border between Dagestan and Azerbaijan. RESULTS: Cytochrome b mt-DNA of genus Mus research in this study in the Eastern Caucasus. About 70% of M. musculus haplotypes from the lowlands of Dagestan were recorded for the first time. One of these haplotypes accounts for approximately 25% of the total species diversity of haplotypes. M. macedonicus was found in only one locality, the Sarykum barchans, where this species prevails in number and accounts for 70% of the total number mice of the genus Mus. The species is characterized by low values of genetic diversity and nucleotide variability, which may indicate that the population originated from a small number of founders and may explain its relative isolation from the main range. The dating of the appearance of the ancestors of M. musculus in the east of the Russian Caucasus corresponds to 99-66 thousand years ago (at a mutation rate of 3-10% per million years). CONCLUSION: The results obtained suggest that the history of the appearance of M. musculus in the Eastern Caucasus is more ancient and is not associated with human agricultural activities. We believe that possibly the ancestral range of M. musculus covered the eastern and western coasts of the Caspian Sea in the territory of southern Dagestan, Azerbaijan, and Iran. In this paper M. macedonicus, a Balkan-Asia Minor species, was registered for the first time in the North Caucasus. This species was registered in the center of Dagestan, where it inhabits sympatrically (on the territory) and syntopically (on the same biotope) with M. musculus. The low values of genetic diversity of M. macedonicus in the North Caucasus suggest that the population originated from a small group of founders.
RESUMO
Patterns of body size variation along geographical gradients have long been searched for and generalized into eco-geographical rules. However, no rodent species has yet been analyzed in relation to the 3 dimensions of latitude, longitude and altitude. We analyzed geographical clines and dimorphism of body and skull size in the herb field mouse (Apodemus uralensis) across the species range, based on field data and on data from the literature. Sexual dimorphism in adult A. uralensis was not expressed at a large scale, while local patterns were inconsistent. Age-dependent size changes were most expressed in adult individuals: most characters of adults exceeded in size those of subadults, while subadult-juvenile size differences were only significant in body weight and length, zygomatic skull width, length of cranial diastema and breadth of braincase. Despite central morphological niches along the clines being separated, A. uralensis populations showed a high degree of size overlap in morphological space. We found the species to be characterized by high size variability, with the largest individuals inhabiting the eastern and southern edges of the distribution range. Tail, hind foot and ear lengths were largest in the southern part of the range, in agreement with Allen's rule. The main measurements that we analyzed, namely body mass, zygomatic skull width and condylobasal skull length, show the presence of 3 clines in the size of adult A. uralensis: (i) a decreasing south-north cline, opposing Bergmann's rule; (ii) an increasing west-east cline, in accordance with Murphy's rule; and (iii) an increasing altitudinal cline.
