Large African Barbs: Vectors of Diversification of Individuals of the Generalized Form as the Source of Phenetic Diversity of the Barbus intermedius Complex in Lake Tana, Ethiopia

Abstract

The paper analyzes the morphological diversification of individuals of the generalized form of the Barbus intermedius complex in comparison with the diversification of specialized morphotypes and allopatric species of large African barbs. In the sets of generalized individuals, four main vectors of diversification are revealed, while two each are revealed in morphotypes and species. Comparison of peer-to-peer diversification vectors of monomorphic populations of generalized individuals from Langano and Awasa lakes reveals their similarity and essential differences from the corresponding diversification vectors of generalized individuals from Lake Tana. The vectors of diversification of the Lake Tana morphotypes are very similar to both peer-to-peer vectors of allopatric species and to the vectors of the Lake Tana generalized form. This high degree of similarity suggests that the diversification of individuals of the generalized form in Lake Tana, diversification of the Tana morphotypes, and diversification of allopatric species are successive stages of one process, and diversification of morphotypes and species proceeds in the directions specified by diversification of individuals of a generalized form. The results of the study may be considered as strong evidence in favor of the hypothesis of proximity (or identity) of a generalized form and the ancestral form, which gave rise to the diversity of the B. intermedius complex. The study is based on the assessment of correlations between the characters of individuals of the studied sets.