THE TRICORYTHIDAE OF THE ORIENTAL REGION

摘要

Based on detailed taxonomic revision of predominantly larval material of the family Tricorythidae (Ephemeroptera) so far available from the Oriental Region, a new genus, Sparsorythus gen. n., is established to include six new species: S. bifurcatus sp. n. (larva, imago male and female), S. dongnai sp. n. (larva, imago male and female), S. gracilis sp. n. (larva), S. grandis sp. n. (larva), and S. ceylonicus sp. n. (larva), and S. multilabeculatus sp. n. (imago male), respective differential diagnosesare presented. S. jacobsoni (Ulmer 1913) comb. n. is transferred from the genus Tricorythus, now supposed to cover only a part of Afrotropic species of this family. Further five species are described but left unnamed since the larval stage is still unknown. The egg stage (a single polar cap and usually hexagonal exochorionic structures) is described for the first time, relationships of Sparsorythus gen. n. to all other genera of the family and their composition are discussed with regard to classical extent of knowledge and rather confusing data in the past. Available data on biology of this new genus are summarized and its distribution with regard to historical biogeography id briefly discussed.