PHYLOGENY OF THE INFRAORDER CULICOMORPHA (DIPTERA, NEMATOCERA) BASED ON 28S RNA GENE-SEQUENCES

Phylogenetic relationships between the families of the infraorder Culi comorpha were investigated by using partial 28S ribosomal RNA gene seq uences. All families traditionally placed in this infraorder were inve stigated and confirmed as clades. On the other hand, some of the morph ological relationships between these families were found to be in disa greement with phylogenies based on molecular characters. Our results d id not support the generally accepted division of the Culicomorpha int o two superfamilies, the Culicoidea (Culicidae + Corethrellidae + Chao boridae + Dixidae) and the Chironomoidea (Chironomidae + Ceratopogonid ae + Simuliidae + Thaumaleidae). Precisely, if the sister-group relati onship between Culicidae, Chaoboridae and Corethrellidae was clearly c onfirmed, the Dixidae, traditionally considered as closely related to these two families, were not placed close to them on our trees. On the other hand, strong evidence was found for grouping together the Simul iidae and the Thaumaleidae, in spite of the cytological and morphologi cal differences between these two families. The position of the Cerato pogonidae was uncertain, and the Chironomidae appeared as a possible s ister group to the rest of Culicomorpha. The phylogenetic positions of the groups characterized by feeding on vertebrate blood or insect hae molymph (the Culicidae, Chaoboridae, Ceratopogonidae and Simuliidae) s uggest that haematophagy has appeared at least twice in the evolution of Culicomorpha.