Three distinct but rare kovalevisargid flies from the Jurassic Daohugou biota, China (Insecta, Diptera, Brachycera, Kovalevisargidae)

Three nearly complete male specimens of kovalevisargid flies are described as Kovalevisargus macropterus sp. nov., K. brachypterus sp. nov. and Kerosargus sororius sp. nov. (family Kovalevisargidae) from the Callovian-Oxfordian Daohugou biota in Inner Mongolia, China. These extend the range of the family Kovalevisargidae outside of Central Asia for the first time, reveal new morphological details about kovalevisargid flies and offer new evidence for the biostratigraphic correlation of nonmarine sedimentary strata of both the Karabastau and Daohugou Formations. Close similarities in the composition of insect taxa from both entomofaunas imply not only the geological age but also the sedimentary environment at that time being the same, or nearly so. Familial and generic diagnoses of kovalevisargid flies are supplemented based on information derived from these new species.