Drosophila koepferae: a New Member of the Drosophila serido (Diptera: Drosophilidae) Superspecies Taxon1

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Abstract
Drosophila koepferae Fontdevila et al., n. sp., is a member of the D. buzzatii cluster (D. mulleri complex) of the D. repleta species group of the genus Drosophila. It is distinguished from its sister species, D. serido, by morphological, genetic, ecological, and reproductive criteria. Chromosomal differentiation has led to standard sequences and inversion polymorphisms characteristic for each species. Genetic distance between both species measured by allozyme loci polymorphisms is in the range of true species and by itself justifies species status. In laboratory tests involving mass cultures with no choice, interspecific matings take place. Gene exchange between the two species is theoretically possible, for fertile hybrid females as well as sterile hybrid males are produced. However, both species have developed a strong premating isolation and also appear to be allopatric. In view of the marked differences between the two species, it is very improbable that any significant gene flow could occur in an area of sympatry, if such a region does exist. The extreme biological diversity of known D. serido populations suggests that the species may qualify as a superspecies.