Description of a new species of the genus Sarasaeschna Karube & Yeh, with a key to the species of Taiwan (Odonata: Anisoptera: Aeshnidae)

Sarasaeschna chiangchinlii sp. nov. collected from Daxi, Taoyuan County in northern Taiwan is described and diagnosed. Judging from male penile structure, this species is considered to belong to the pryeri-group of its genus. It is easily distinguished from all known congeners in having peculiar sickle-shaped cerci in male. The habitats of S. chiangchinlii are mainly shaded brooks in lowland areas, which are exceptional for its Taiwanese relatives. Distributional maps and a key are also provided for the four species of Taiwanese Sarasaeschna.