The ercepeae Complex: New Cases of Insular Speciation within the Drosophila ananassae Species Subgroup (melanogaster Group) and Descriptions of Two New Species (Diptera: Drosophilidae)

Abstract

Two new species of the Drosophila ananassae subgroup are described. D. comorensis Tsacas sp. n. and D. merina Tsacas sp. n. are endemic to the Indian Ocean islands Comores and Madagascar, respectively. Comparisons with 2 other species, also endemic to Indian Ocean islands and belonging to the D. ananassae subgroup, D. ercepeae Tsacas & David from La Réunion and D. vallismaia Tsacas from Seychelles, lead to the definition of a 3rd complex, ercepeae, within this subgroup. Relationships among the 4 species of the ercepeae complex are based on morphological data (the only data available for D. comorensis), mitotic and polytene chromosome analyses, behavioral interactions, interspecific hybridizations, chemical analyses of cuticular hydrocarbons, and amylase polymorphism. Within this complex, D. ercepeae and D. merina are distinguished from D. vallismaia and D. comorensis. All characters show close affinities between D. ercepeae and D. merina. The geographic distribution of the species of the 3 complexes of the D. ananassae subgroup is also discussed.