Triassic Diptera and initial radiation of the order

New Triassic Diptera Nematocera from Central Asia are described: Mabelysia chadesi (Limoniidae), Gnomusca molecula and G. renysa (?Limoniidae, Gnomuscinae subfam. n.), Vymrhyphus tuomikoskii and V . triassicus (Protorhyphidae, Anisopodoidea), Nadiptera Raluginae and N . pulchella (Nadipteridae fam. n., Ptychopteroidea), Vladipfera Rovalmi, Dilemma/a specu/a, Psychotipa predicta, and P. depicta (all Vladipteroidea superfam. n. and Vladipteridae fam. n., two latter Psychotipinae subfam. n.), Kuperwoodia benefica and Anemeca l iya (both Hennigmatoidea superfam. n. and Hemigmatidae fam. n., the former Kupenvoodiinae subfam. n.). The type of the latter family, Hentiigma cladistorum, is described from the Cretaceous of Mongolia, and Nadipfera anachrona from the Jurassic of Kyrgyzstan. Mesozoic Eoptychopteridae are divided into three subfamilies. The Jurassic family Ansorgiidae is transferred into Blephariceroidea; Triassic Alinkidae is provisionally assigned to Pachyneuroidea. The most primitive dipterans, Vladipteridae, are placed in Tipulomorpha. The radiation of Nematocera is discussed (original phylochronograrn and modified system given); some infraordinal concepts are criticized. The origin of Diptera from Permian Mecoptera similar to Robinjohniidae is suggested; it's hypothesized that the dipteran wing structure was formed mainly due to transfer of mecopteran hindwing characters onto the forewing.