Animal Science and Food Technology

The results of analysis of the taxonomic richness, diversity and complexity of the freshwater fish assemblages in southeastern Europe over the last 12 million years are presented in the paper. It has been established that values of taxonomic richness of these paleocommunities tend to decrease with decreasing the geological age. The impoverishment of the faunistic composition was manifested in a decrease in the number of taxa at all hierarchical levels and could be caused by periodic changes in the hydrological regime. The species and genus diversity is also significantly reduced in a stratigraphically consistent series of groups. At the same time, there is an increase in diversity at the level of families and orders, thereby increasing the taxonomic diversity and complexity of the studied assemblages. During long periods of geological time in relatively stable conditions of the freshwater environment, the ichthyofauna preserves the unity of its composition. The taxonomic similarity of individual ichthyofauna communities is greater when they represent the smaller segment of geological time. This is due to the greater homogeneity of the geoclimatic conditions in which these communities existed. A significant number of pairs of paleocommunities that have more than half of the common taxa testifies to the continuity in the development of the freshwater ichthyofauna of southeastern Europe during the late Cenozoic and is due to their narrow biotopic spectrum and geographical proximity of investigated localities.

freshwater fish, Cenozoic, taxonomic richness, diversity, faunal similarity, Eastern Europe