Dasyatis laosensis,a new whiptailed stingray (family Dasyatidae), from the Mekong River of Laos and Thailand

Synopsis Dasyatis laosensis, a new species, is described from the Mekong River where it forms the border between Laos and Thailand. It is the first member of the genus Dasyatis to be described as an endemic freshwater species from Southeast Asia. Bright orange color on the ventral surface of the disc and similar meristic characters indicate that it may be closely related to Dasyatis akajei, a marine species from southern Japan and China, and to Dasyatis sp. undetermined, from the West River in Guangxi, southern China.