Phytogeny of the nematocerous families of Diptera (insecta)

The relationships of the nematocerous families of Diptera are cladistieally analysed using the parsimony programs PAUP and Hennig86. An extensive review, as well as a data matrix, is presented for 98 almost exclusively morphological characters (larva, 56; pupa, 6; adult, 36). Four infraorders are recognized, viz , Ptychopteromorpha, Culicomorpha, Blephariceromorpha, Bibionomorpha, and a clade containing the 'higher Nematocera' and Brachycera. Traditionally the family Nymphomyiidae or the infraorder Tipulomorpha (=Tipulidae, with or without Trichoceridae) are considered the most basal clade of the extant Diptera. On the basis of our cladistic analysis it is suggested that the Ptychopteromorpha-Culicomorpha clade is the sister-group of all other extant Diptera. We provide evidence that the Axymyiidae are part of a monophyletic Bibionomorpha. The latter infraorder is proposed as the sister-group of the higher Nematocera and Brachycera. We transfer the Tipulidae (Tipulomorpha) to the higher Nematocera, at a position next to Trichoceridae and near the Anisopodidae-Brachycera lineage. Previous hypotheses concerning nematocerous relationships are reviewed.