Содержание: Том 3 (1) 2004 (отпечатан 31 October 2004)
Interpretation of the dentition in the holotype of Peraiocynodon inexpectatus Simpson, 1928 as d1–4 (Butler, 1939) is confirmed. Two taxa of docodonts from the British Middle Jurassic are based on the lower milk teeth: Cyrtlatherium canei and Peraiocynodon major. Simpsonodon oxfordensis Kermack et al., 1987 is a junior subjective synonym of Cyrtlatherium canei Freeman, 1979 (syn. nov.) and Peraiocynodon major Sigogneau-Russell, 2003 is a junior subjective synonym of Krusatodon kirtlingtonensis Sigogneau-Russell, 2003 (syn. nov.).
Lopatin A.V., Tesakov A.S.
Cretasorex arkhangelskyi Nessov et Gureev, 1981 was described from the Upper Cretaceous of Uzbekistan as the earliest member of Soricidae. Later, it was reevaluated as the Late Cenozoic soricid. The reexamination of the holotype demonstrates the reference of this soricid to the tribe Soricini, and, more specifically, the group of Sorex s.l. Indirectly it suggests an age not older than Late Miocene. The separate generic rank is possible for this form.
Kuznetsov G.V., Borissenko A.V.
The first record of Tragulus versicolor Thomas, 1910 outside its type locality is described. One specimen was collected in the vicinity of Dak Rong and Boun Luoi, ~20 km north of Kan Nack (Gia Lai Province, Central Vietnam), collected in 1990 and deposited in the Zoological Museum of Moscow University. Peculiar external characters (pelage coloration pattern) indicate its authenticity from the sympatrically occurring T. kanchil (Raffles, 1821). Certain aspects of morphological differences between the two species and conservation issues relevant to the new finding are being discussed.
Oshida T., Shafique Ch. M., Barkati S., Fujita Y., Lin Liang-Kong, Masuda R.
Phylogenetic relationships among five species of the genus Petaurista (P. alborufus, P.elegans, P. leucogenys, P. petaurista, and P. philippensis) were investigated using the complete cytochrome b gene sequences (1140 bp). Phylogenetic trees indicated (1) P.alborufus castaneus from southern China was closely related to P. petaurista albiventer from Pakistan, (2) P. alborufus lena from Taiwan, P. petaurista melanotus from China and Laos, and P. philippensis grandis from Taiwan were grouped, and (3) P. leucogenys, which is endemic to Japan, distinctly separated from other species. Our results critically refuse the present classification in Petaurista, and suggest that it is reasonable to regard P. alborufus lena as a distinct species from P. alborufuscastaneus, and P. petaurista albiventer as a distinct species from P. petauristamelanotus.
The significance of hybridisation in the evolution and diversification of commensal taxa of Mus musculus s.l. species group is discussed. Allozyme analysis has shown that Transcaucasian populations of commensal house mice possess an admixture of musculus and domesticus genes. This region is either a zone of secondary contact between musculus and domesticus, with very wide introgression of domesticus genes into the genome of musculus, or these are relict populations descended from non-differentiated forms with ancestral polymorphism. The main feature of this zone is the unusually large extent of domesticus genes, which occur throughout the entire Transcaucasia (about 350 000 km 2 ). Data and observations favour the view suggest that Transcaucasian house mouse populations are relicts of an early-differentiated form of M. musculus, preserving much of the ancestral gene pool. The second possible hypothesis is that populations of Transcaucasia are result of hybridisation of ancient not finally differentiated forms of house mice. It is possible that ancient “oriental” lineage and ancient form of musculus were colonised the Transcaucasia and mixed in this territory. The Adzharian populations would then be a product of contact between these forms and early of fully differentiated M. domesticus from Turkey. Large zones of hybridisation are present also in other regions of Asia. Analysis of hybrid populations of house mice in Russia demonstrates the particular significance of hybridisation in the evolution of commensal taxa. This enhanced role in commensals is linked to their unique ability to expand their geographic ranges through human agency and even survive as commensals in areas that are beyond their physiological tolerance.
Smorkatcheva A.V., Smolnyakova E.S.
Group-living and cooperative breeding in the mandarin vole Lasiopodomys mandarinus were proposed to be an adaptation (or preadaptation) to the fossorial mode of life (Smorkatcheva, 1999). This hypothesis involved indirect benefits that gain offspring by helping their mother in tunnel construction among the factors promoting cooperative breeding. Answer to the question “which animals do provide the most help?” may allow us to understand whether helpers derive direct or indirect benefits from their action. In this study we compared the contributions to nest-residence, digging, bringing objects, eating and the digging/eating rates between different sex-age categories. We observed groups composed of pair of breeders, 1-9 weaned offspring and unweaned pups in artificial tunnel systems. Only daughters older 35 days participated extensively (along with their fathers) in transport and burrow construction. Overall, the digging/eating rate was greater in daughters than in mothers. This provides evidence that young females perform some excess workload to be used up, potentially, by reproductive female. Sons, independently of their age, and daughters under 35 days were engaged very little (lesser than other members of families) in burrow construction and transport. Sons under 60 days, daughter older 60 days and fathers were the major baby-sitters. Sex differences in degree of the most expensive activities are inconsistent with the kin-selection hypothesis, but can be explained in the framework of delayed reciprocity or group augmentation hypothesis. Another (non-alternative) explanation of the revealed sex-bias is that burrow construction would be parental, not only alloparental, investment for daughter should it attain a breeding position at natal territory.
The possibility of age determination of pikas using tooth row condition, development of crests on the angular process of the dentary, ossification of the skull and development of the skull crests, as well as condition of the reproductive system is discussed. Age variability of the features above is described. The methods allow determining individual age of pikas up to about four months old. Subsequently, morphological differences between specimens born this year and over wintered ones become obscured, but some difference in skull proportions may be retained for some time.