Altai Osmans of the Genus Oreoleuciscus and African Barbs of the Barbus intermedius Complex: the Common Patterns of Morphological Differences Between Piscivorous and Non-Piscivorous Forms under Sympatry Conditions

In populations of fish species of the same and of different systematic groups living in lakes of the same and of different continents the patterns of differences in factor loadings of the considered parameters of the morphology of the jaw apparatus and neurocranium on the main vectors of variability in comparison of piscivorous and non-piscivorous ecological forms almost coincides. It is shown that in the Altai osmans of the Oreoleuciscus potanini species in two lakes of the Central Asian Closed Basin, the structure of differences is almost identical to the structure of differences between the piscivorous and non-piscivorous forms of the barbs of the Barbus intermedius complex sensu Banister (1973) complex in the African Lake Tana. At the same time, the structure of the differences between the piscivorous and non-piscivorous forms of another species of Altai Osmans Oreoleuciscus humilis in a lake located in another part of the Central Asian Closed Basin differs significantly from the structure of differences in ecological forms of both the O. potanini species and the B. intermedius complex. It is assumed that the following explanation may be given for the revealed difference in the variability of Osmans in the studied water bodies. In the African lake Tana and Mongolian lakes Bayan and Khar-Us, the structure of differences reflects the already established situation of stationary coexistence of piscivorous and non-piscivorous forms in one water body. Whereas the structure of variability in the periodically drying Mongolian lake Lake Orog reflects not an established situation, but an incomplete process of its formation, interrupted over and over again by the death of the lake population in the next drought period.