The monophyletic Schizophora are classified into at least 80 families and comprise just over half the family-level diversity in Diptera. Major reviews of Schizophora phylogeny are the synthetic revisions by Griffiths (1972) and McAlpine (1989) which provided new information while building on Hennig's earlier research. Griffiths (1972) provided detailed interpretation and scorings of male genital characters along with other morphological features, and McAlpineÕs (1989) fully resolved phylogenetic arrangements draw on most morphological character systems as well fly biology. Based on calypter morphology the Schizophora have been traditionally subdivided into the Acalyptratae and Calyptratae, but it has long been recognised that the calypter is too variable in both groups to be a reliable phylogenetic marker. Although the former is supported on our supertree it is generally regarded as being paraphyletic.
McAlpine (1989) divided the Acalyptratae into 10 superfamilies and these are found in the supertree: Nerioidea, Diopsoidea, Conopoidea, Tephritoidea, Lauxanioidea, Sciomyzoidea, Opomyzoidea, Sphaeroceroidea, Carnoidea, and Ephydroidea. Only few superfamilies are uncontentious (e.g., Ephydroidea, Tephritoidea) while the remaining will probably see some major rearrangements after more intensive phylogenetic scrutiny. Generally, McAlpine's (1989) classification maintains Hennig's (1973) groupings while Griffiths (1972) proposes a more radical restructuring. In contrast to the Acalyptratae and despite the lack of complex morphological autapomorphies, the Calyptratae appear monophyletic based on molecular and morphological evidence. Of the three superfamily-level taxa, the Hippoboscoidea are monophyletic, the Oestroidea may be monophyletic, while the Muscoidea is likely paraphyletic.
Advances in understanding the relationships of flies will accelerate with the increasing use of molecular data and quantitatively analysed data matrices. The National Science Foundation has recently funded a five-year collaborative initiative to generate a phylogeny of Diptera (see www.diptera.org). The project will compile gene sequences, full mitochondrial genomes and complete phenotypic character matrices for members of all fly families.
The most important areas for future phylogenetic research in the Diptera are in the Lower Diptera and Schizophora. In the Lower Diptera, resolving the relationships between the infraorders and the position of the craneflies and their relatives (Tipulidae) are critical tasks. The Schizophora also await more focused phylogenetic scrutiny applied to relationships between, and within, the superfamilies as they are currently defined.
|
