Monophyly and relationships of the Tabanomorpha (Diptera : Brachycera) based on 28S ribosomal gene sequences

Higher-level relationships among the earliest lineages of brachyceran Dipte ra remain poorly resolved by comparative morphology. Nucleotide sequence da ta should be useful in clarifying brachyceran relationships, especially whe re morphological evidence is either contradictory or controversial. We exam ined phylogenetic relationships among the family-level taxa of the brachyce ran infraorder Tabanomorpha using sequences of a large portion df the 28S r ibosomal DNA. Twenty-five species were sequenced, including five outgroup s pecies from the Stratiomyomorpha and Xylophagomorpha. Parsimony and maximum likelihood-based phylogenetic analysis of 2,371 alignable sites yielded id entical inferred tree topologies. 28S rDNA supports the monophyly of the Ta banomorpha (Vermileonidae, Rhagionidae, Pelecorhynchidae, Athericidae and T abanidae). Our results contradict several published hypotheses that associa te Vermileonidae with asiloid or eremoneuran taxa remote from the Tabanomor pha. The molecular data also support monophyly for all of the included fami ly-level lineages, and corroborate several recent phylogenetic hypotheses b ased on comparative morphology.