New data on the mitochondrial genome of Nematocera (lower Diptera): features, structures and phylogenetic implications

Nematocera (lower Diptera) is a taxonomically diverse group with similar to 52 000 species in 40 families, including many important agricultural and sanitary pests. The number and composition of nematoceran infraorders have long been subject to debate. The use of mitochondrial genomes for resolving these questions shows considerable promise. Herein, we sequenced and annotated the complete or nearly complete mitochondrial genomes of eight nematoceran species from seven families, representing the first mitochondrial genomes of two infraorders and six families. They range in size from 14 447 to 16 255 bp and all contain 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and an AT-rich region. Like other nematocerans, the arrangement of genes of their mitochondrial genomes is identical to the presumed ancestral arrangement. A phylogenetic analysis was conducted by using mitochondrial genomes of 116 representatives from Diptera, Mecoptera and Siphonaptera. Our phylogenetic results support both new and traditional arrangements. The small, highly specialized family Deuterophlebiidae appears to be sister to all remaining Diptera, while Nymphomyiidae and Blephariceridae are nested within Culicomorpha and Psychodomorpha, respectively; hence, the recognition of `Blephariceromorpha' as a valid monophyletic infraorder is discouraged. Anisopodidae is supported as the sister group of Brachycera.