Phylogeography and molecular systematics of species complexes in the genus Genetta (Carnivora, Viverridae)
Fernandes, Carlos Alberto Rodrigues
The main aim of this study was to estimate phylogeographic patterns from mitochondrial DNA diversity and relate them with evolutionary structure in two species complexes of genets, Genetta genetta and Genetta "rubiginosa",which have fluid morphological variation. Both are widely distributed in sub-Saharan Africa but whereas G. "rubiginosa" appears in both closed and open habitats, G. genetta is absent from the rainforest and occurs also in the Maghreb, southwest Europe, and Arabia. DNA sequence data, mainly acquired from museum skin samples (about 75% of the total number of samples), was analysed using methods from the fields of phylogenetics and population genetics. The results for G. genetta are compatible with a scenario of allopatric fragmentation in grassland refuges during the Pleistocene climatic cycles as the main factor responsible for geographic genetic structure within Africa. The Arabian isolate showed significant genetic divergence, species-level compatible, and is probably the result of a long-distance dispersal from North Africa. Genetic diversity in Europe is a subset of that found in North Africa and shallow genetic distance is concordant with their anthropogenic introduction into Europe. North Africa seems to be cyclically connected to West and Central Africa during interglacial periods in which the Sahara recedes substantially. For G. "rubiginosa", isolated biogeographic relicts in the eastern African coast, possibly unsuspected species, were uncovered. However, the dominant pattern in the evolution of this species complex seems to be ecological differentiation in parapatry after invasion of open habitats from the rainforest ancestral habitat. Three general conclusions may be extracted from this study. Firstly, the use of mitochondrial DNA is clearly informative, but both gene flow among parapatric populations and introgression are confounding factors. Secondly, the Pleistocene in Africa has had variable biogeographical and evolutionary consequences for different taxa, depending on their ecological breadth. Lastly, large-scale utilisation of museum samples in phylogeographies of cryptic taxa has been rarely attempted but should become a standard approach.
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