Molecular phylogeny of the Calyptratae (Diptera: Cyclorrhapha) with an emphasis on the superfamily Oestroidea and the position of Mystacinobiidae and McAlpine's fly

Abstract

The dipteran clade Calyptratae is comprised of approximately 18 000 described species (12% of the known dipteran diversity) and includes well-known taxa such as houseflies, tsetse flies, blowflies and botflies, which have a close association with humans. However, the phylogenetic relationships within this insect radiation are very poorly understood and controversial. Here we propose a higher-level phylogenetic hypothesis for the Calyptratae based on an extensive DNA sequence dataset for 11 noncalyptrate outgroups and 247 calyptrate species representing all commonly accepted families in the Oestroidea and Hippoboscoidea, as well as those of the muscoid grade. DNA sequences for genes in the mitochondrial (12S, 16S, cytochrome c oxidase subunit I and cytochrome b) and nuclear genome [18S, 28S, the carbamoyl phosphate synthetase region of CAD (rudimentary), Elongation factor one alpha] were used to reconstruct the relationships. We discuss problems relating to the alignment and analysis of large datasets and emphasize the advantages of utilizing a guide tree-based approach for the alignment of the DNA sequences and using the leaf stability index to identify 'wildcard' taxa whose excessive instability obscures the phylogenetic signal. Our analyses support the monophyly of the Calyptratae and demonstrate that the superfamily Oestroidea is nested within the muscoid grade. We confirm that the monotypic family Mystacinobiidae is an oestroid and further revise the composition of the Oestroidea by demonstrating that the previously unplaced and still undescribed 'McAlpine's fly' is nested within this superfamily as a probable sister group to Mystacinobiidae. Within the Oestroidea we confirm with molecular data that the Calliphoridae are a paraphyletic grade of lineages. The families Sarcophagidae and Rhiniidae are monophyletic, but support for the monophyly of Tachinidae and Rhinophoridae depends on analytical technique (e.g. parsimony or maximum likelihood). The superfamilies Hippoboscoidea and Oestroidea are consistently found to be monophyletic, and the paraphyly of the muscoid grade is confirmed. In the overall relationships for the calyptrates, the Hippoboscoidea are sister group to the remaining Calyptratae, and the Fanniidae are sister group to the nonhippoboscoid calyptrates, whose relationships can be summarized as (Muscidae (Oestroidea (Scathophagidae, Anthomyiidae))). © 2010 The Authors. Systematic Entomology © 2010 The Royal Entomological Society.