Valeseguyidae, a new family of Diptera in the Scatopsoidea, with a new genus in Cretaceous amber from Myanmar

The genus Cretoseguya, gen.n., is described for C. burmitica, sp.n., based on a female found in mid-Cretaceous amber from Myanmar. Valeseguya Colless was classified previously as a subfamily of the 'woodgnats', family Mycetobiidae (Anisopodoidea). Thoracic and male terminalia morphology of Valeseguya rieki Colless, from the Recent of Australia, and V. disjuncta Grimaldi, in Miocene amber from the Dominican Republic, are redescribed. The new family Valeseguyidae includes two species in Valeseguya and one in Cretoseguya. Phylogenetic analysis of characters on the head, wing (venation), legs, terminalia and, especially, thoracic pleural sclerites indicate that the correct placement of the family is as the sister group to the 'scavenger gnats' Scatopsidae + Canthyloscelidae (including Synneuron). The concept and definition of Scatopsoidea are expanded to include these three families.