Main Article Content
An illustrated morphological description of two new species of the genus Diamesa Meigen, 1835 are provided from Tien Shan and Pamir mountains: D. akhrorovi sp. nov., as male adult; D. alibaevae sp. nov., as male adult and pupa. DNA barcoding results of the two new described species with comparative database on some related Diamesa species are also given. The two new described species key both near D. planistyla Reiss, 1968, which was known from Nepal and redescribed here from Tian Shan. The diversity of Diamesa genus using three mitochondrial (COI, COII, 16S rRNA), two nuclear (18S rRNA, EF-1a) markers and estimating phylogenetic relationships is also highlighted. Six of the studied Diamesa species including D. akhrorovi sp. nov. and D. alibaevae sp. nov. represent a well-supported monophyletic clades with high Bayesian posterior probability, while D. cinerella Meigen and D. hamaticornis Kieffer have a lower interspecific sequence divergence.