Burmagomphus asahinai sp. nov., a new species from Cambodia and Thailand, with a description of the male of B. gratiosus Chao, 1954

Burmagomphus asahinai sp. nov. (holotype ♂: Cambodia, Cardamom Mts., Koh Kong Province, Thma Bang District, 6 km SW of its centre, rapids at the Thma Bang River, 25 August 2011, RMNH) is described from Koh Kong Province of Cambodia and Nakhon Nayok, Chiang Mai and Parchuap Khiri Khan Provinces of Thailand and is compared with its nearest congeners. While the mesepisternum pattern is closest to that of B. gratiosus Chao, 1954, the female head sculpture combines structures found separately in B. gratiosus and B. williamsoni Forster, 1914. A redescription of B. gratiosus, including the hitherto unknown male, is provided based on a pair from Guizhou Province, China.