Bibionomorpha

Definition

An infraorder of true flies (Diptera) within the suborder Nematocera, encompassing fungus gnats, march flies, and related groups. The infraorder includes several superfamilies—Bibionoidea (march flies), Sciaroidea (fungus gnats and gall midges), and others—derived historically from the formerly broad family Mycetophilidae. The Anisopodidae (wood gnats) within this infraorder are phylogenetically significant as the presumed sister taxon to the entire suborder Brachycera (short-horned flies). Recent revisions have removed the family Axymyiidae to its own infraorder Axymyiomorpha.

Etymology

From the genus Bibio (march flies) + Greek -morpha ('form, shape'), referring to the characteristic morphology of constituent taxa

Example

Adult Bibionidae (march flies) in the Bibionomorpha are familiar spring emergents in temperate regions, often forming mating swarms; their larvae are important soil decomposers, while the Sciaroidea include economically significant pests such as the Hessian fly (Mayetiola destructor) and diverse mycophagous species critical for fungal spore dispersal.

Related Terms

• Nematocera
• Brachycera
• Diptera
• Mycetophilidae
• Sciaroidea
• Bibionidae
• Anisopodidae
• Axymyiomorpha
• infraorder

Usage Notes

The composition of Bibionomorpha has been unstable due to ongoing phylogenetic revision; specialists should verify current family-level assignments. The group is primarily defined by larval ecology—many are saprophagous, mycophagous, or phytophagous in soil, decaying wood, or fungi—rather than by conspicuous adult synapomorphies. Contrast with Psychodomorpha and Culicomorpha, the other major nematoceran infraorders.