Anisopodidae is a small cosmopolitan family of gnat-like flies known as Wood gnats or Window-gnats with 154 described extant species in 15 genera, and several described fossil taxa. Some species are saprophagous or fungivorous. They are mostly small to medium-sized flies, except the genera Olbiogaster and Lobogaster, which are large with bizarrely spatulate abdomens. Their phylogenetic placement is controversial. They have been proposed to be the sister group to the higher flies, the Brachycera (Oosterbroek and Courtney 1995). Some authors (Amorim and Grimaldi 2006) consider this group to be four distinct families- Anisopodidae, Mycetobiidae, Olbiogastridae, and Valeseguyidae.
Oosterbroek, P. and G. Courtney. 1995. Phylogeny of the nematocerous families of Diptera (Insecta). Zoological Journal of the Linnean Society 115:267-311.