The phylogeny of Strepsiptera (Hexapoda).

Abstract

Previous phylogenetic analyses of Strepsiptera have been limited to characters from only males or first instar larvae, and by poor taxonomic sampling. This investigation is the first cladistic analysis to use more than fourfold as many characters as any prior study, and a broader sampling of taxa. The analysis of 189 morphological characters of all stages of representatives of all extant strepsipteran families and characters of adult males of amber fossils results in the following branching pattern: (†Protoxenos+ (†Cretostylops + (†Mengea + (Mengenillidae + (Corioxenidae + (Bohartillidae + (Halictophagidae + (Elenchidae + (†Protelencholax + (Myrmecolacidae + (Callipharixenidae + (Xenidae + Stylopidae)))))))))))). The basal placement of the Baltic amber fossil †Protoxenos and the Burmese amber fossil †Cretostylops is well founded. Even though †Cretostylops is older than †Protoxenos it is almost certainly not the most basal strepsipteran group but the sister group of a clade comprising the Baltic amber fossil †Mengea + Strepsiptera s. str. (excl. stemlineage). Monophyly of Mengenillidae, Stylopidia, Stylopiformia s.l., Corioxenidae, Xenidae, and Stylopidae is confirmed. Mengenillidia is paraphyletic (with respect to †Mengea (Mengeidae)), Elenchidae (with respect to †Protelencholax) and the genus Stichotrema (with respect to the Baltic amber fossils). Thus Protelencholacidae fam. n. is described, and S. weitschati and S. triangulum are transferred to Palaeomyrmecolax. A ground plan of adult male Strepsiptera is provided and evolutionary interpretations are presented based on the obtained cladograms.