Terrestrial fishes: rivers are barriers to gene flow in annual fishes from the African savanna.

摘要: Aim We compared the genetic variability and phylogeographical structure of three sympatric clades annual killifishes (the Nothobranchius furzeri complex, N. orthonotus complex N. rachovii complex) inhabiting annually desiccating savanna pools. Hypotheses on mechanisms affecting intraspecific structure speciation were tested. Location Temporary pools in Mozambique (Africa). Methods The study is based spatially detailed samples covering entire range all species complexes. A set 12–13 microsatellites (1638 individuals, 96 populations) cytochrome b sequences (463 fish, 152 populations) used as markers. Phylogenetic and population approaches to describe spatial genetic structure test respective roles river channels river basins diversification. Results Profound genetic differentiation among populations was evident; some populations located only a few kilometres apart were genetically very distinct, suggesting significant role of genetic drift low dispersal ability. Large rivers (Zambezi, Save, Limpopo) formed major barriers gene flow, with minor differences complexes. Further, demographic expansion previously isolated lineages often limited by the channel, also confirmed factors affecting events. River elevational gradient had smaller, but non-negligible, in population structuring. Main conclusions channels are main barriers flow Nothobranchius fishes. study demonstrated ability congruence the phylogeographical pattern Cases where Nothobranchius appear have crossed result from dynamics morphology rather than from rare dispersal This conclusion supported by simultaneous crossing events across lineages. further division, also consistent complexes, detected between drier inland wetter coastal areas. phylogeographical pattern unique that it combines features both aquatic terrestrial taxa.