Phylogeny of the scathophagidae (Diptera, Calyptratae) based on mitochondrial DNA sequences

The family Scathophagidae constitutes, together with members of the familie s Muscidae, Fannidae, and Anthomyiidae, the Muscoidea superfamily. The spec ies Scathophaga stercoraria has been used extensively to investigate questi ons in animal ecology and evolution, particularly as a model system for stu dies of sperm competition and life history evolution. However, no phylogene tic studies have ever been performed on the Scathophagidae and the relation ships within this family remain unclear. This study represents a molecular approach aimed at uncovering the phylogenetic relationships among 61 specie s representing 22 genera of Scathophagidae. A fragment of the terminal regi on of the mitochondrial gene COI (subunit I of the cytochrome oxidase gene) was sequenced in scathophagid species covering a wide geographic area, as well as a diverse spectrum of ecological habitats. Several clades grouping different genera and species have been identified, but the resolution power of the COI was insufficient to establish the exact relationships between t hese clades. The molecular data confirm the existence of a group consisting of the genera Delina, Chylizosoma, and Americina, which could represent th e subfamily Delinae. Concerning the controversial position of the genus Phr osia, our data clearly suggest that it should be removed from the Delinae a nd placed within the genus Cordilura. Monophyly of most genera was confirme d, except for the genus Scathophaga, which should be divided into several d ifferent taxa. (C) 2000 Academic Press.