DIAGNOSTIC-VALUE OF BACULA IN SOME CRICETIDAE SPECIES FROM PERUVIAN AMAZONIA

Age, individual and geographical variability of bacula in 109 cricetin es belonging to 9 species from 6 genera were studied. Thirteen phenes divided into 4 groups were distinguished according to peculiarities of the bacula structure. Phenograms of all baculas including those in 3 species (Oryzomys macconnelli, O. yunganus and Oecomys trinitatis), pr esented by one specimen, were prepared. Phenocomplexes of baculas in O ligoryzomys microtis, Oryzomys capito and Holochilus brasiliensis of v arious age and those of Neacomys sp., N. spinosus and Nectomys squamip es were distinguished by the maximum frequency of displaying phenes, A ccording to the literature data phenograms of baculas in five species of the nine studied ones were made. A comparative analysis of the obta ined material has revealed a significant individual and age variation of phenes. Geographical variation in O. microtis and H. brasiliensis w as not found. The latter should be taken into account in using peculia rities of the bacula structure in taxonomy of South America cricetines . In many cases the form, size and proportions of this bone may be con sidered as an additional characteristic in species diagnostics.