Phylogeny of Palaearctic Syrphidae (Diptera): evidence from larval stages

We estimated the phylogeny of Palaearctic Syrphidae using 187 larval morphological characters obtained from about 65% of the fauna (85 supraspecific taxa represented by 118 species) and based the analysis at the generic, level. The root of the syrphid tree was established from an outgroup consisting of other Aschizan families: the Platypezidae, Phoridae and Pipunculidae, with the tree rooted on the Lonchopteridae. The Syrphidae was the most derived Aschizan family. The Pipunculidae was the sister group to the Syrphidae. Eumerus was basal within Syrphidae. A trend exists towards increasing complexity of integumental folds and grooves across the Aschiza. In movement, the integument collapses along the line of these grooves. Grooves are evidence of muscles forming functional groups. Elaboration of independent groups of muscles appears to underlie much of the evolution of larval form within Aschiza. The basal feeding modes of syrphid larvae are mycophagy and phytophagy. Above these feeding modes, all remaining syiphids fall into one of two lineages comprising entomophages and saprophages, each of which has a single origin within the apparently polyphyletic Volucella. Major morphological innovation is associated with shifts between feeding modes; within feeding modes, change is gradual and tends towards increasing complexity. Change is mostly in structures associated with the mouthparts, thorax, anal segment and locomotory organs. Generic diagnoses with biological and taxonomic notes and a key to genera using larval characters are provided.