Taxonomic Study On Rhodesiellinae From Xizang Autonomous Region(Diptera: Chloropidae)

The subfamily Rhodesiellinae belongs to the subordinate Acalyptrata,the suborder Brachycera,the order Diptera,and is a smaller subfamily in the family Chloropidae,which contains 13 genera 256 species.This subfamily is distributed in all the zoographical realms.The species of Rhodesiellinae are predominantly diverse in the broad-leaved forests and grass,and adults may feed on plant secretions and honeydew.There are 4 genera 70 species known to occur in China,but the fauna of Rhodesiellinae in Xizang is poorly known with only one recorded species.Xizang has superior natural conditions,complex geographical location and rich biological resources,which provides an ideal place for studying the formation,differentiation and adaptive evolution of biological species.Therefore,the systematics of Rhodesiellinae from Xizang plays an important role in clarifying the faunae of China and world.The results will provide new data to the diversity and distribution pattern of grass flies in Xizang.The present thesis deals with the systematics of Rhodesiellinae from Xizang.The results are as follows:(1)In the taxonomic section,2 genera 38 species are described,including 36 new species(Rhodesiella 34 new species,Dactylothyrea 2 new species),1 newly recorded genus,1 newly recorded species,and 1 new synonym.The world catalogs of Rhodesiellinae are given.The key to separate species of Rhodesiella is made.The dorsal and lateral habitus are provided for each species,and figures of male genitalia from 36 new species are illustrated.(2)Based on the molecular data,the phylogeny of 15 species of Rhodesiellinae from Xizang is studied for the first time combining four mitochondrial genes(COI,Cytb,16 S r RNA,12 S r RNA)and one nuclear gene(28S r RNA).According to the result,the monophyly of genus Neorhodesiella is not supported,which form a monophyletic group with genus Rhodesiella,this result is incongruent with that inferred from the morphological characters.(3)According to the data of the geographical distribution from literatures and specimens,the distribution patterns of Rhodesiellinae are analyzed.It shows that the singleregion pattern is predominant in generic level.the Oriental region holds the richest species diversity of Rhodesiellinae with 13 genera and 57.8% species of total species.It is suggested that the Oriental region is the differentiation center of Rhodesiellinae.Rhodesiellinae are distributed in all Chinese faunae except for the northeast China.There are four genera known from China,which are all distributed in the south China,Rhodesiella is distributed in all regions except northeast China.