On some differences between the left- and right-bank midday gerbils (Meriones meridianus) and M. M. nogaiorum in the lower Volga flow
Tropin, N.N.
Zoologicheskii Zhurnal 59(8): 1217-1224
1980
ISSN/ISBN: 0044-5134 Accession: 006441659
The lower Volga left- and right-bank midday gerbils differ from each other not only by weight and size of body, tail, skull and lower jaw but also by teeth structure. The left-bank subspecies is characterized by the fusion of enamel loops of the lower cheek teeth (87% of cases), as compared with the right-bank one (50%). Some left-bank individuals had opposite triangles in the right upper cheek tooth, rather than the usual oval loops. In the left-bank subspecies, 16% of animals had fused enamel fields of the right upper cheek tooth vs. 4% in the right-bank group. These differences appear to depend on dissimilarity of the natural conditions of the right and left Volga banks which determine the peculiarities of rodents' food composition.