The genus Eurochelidon is possible monotypic taxon with a single species - White-eyed river martin
The white-eyed river martin (Pseudochelidon sirintarae) is a passerine bird, one of only two members of the river martin subfamily of the swallows. Since it has significant differences from its closest relative, the African river martin, it is sometimes placed in its own genus, Eurochelidon. First found in 1968, it is known only from a single wintering site in Thailand, and may be extinct, since it has not been seen since 1980 despite targeted surveys in Thailand and neighbouring Cambodia. It may possibly still breed in China or Southeast Asia, but a Chinese painting initially thought to depict this species was later reassessed as showing pratincoles.
The white-eyed river martin was discovered in 1968 by Kitti Thonglongya, who obtained nine specimens netted by professional bird-hunters as part of a migratory bird survey at a night-time roost at Thailand's largest freshwater lake, Bueng Boraphet, in Nakhon Sawan Province. It was first seen in the wild by ornithologists at the same wintering site in 1977. The species has only been seen at the lake, always between the months of November and February, and the wintering habitat is assumed to be in the vicinity of open fresh water for feeding, with reed beds for the night-time roost.
The white-eyed river martin may be migratory, and if the breeding habitat resembles that of the African river martin, it is likely to be the forested valleys of large rivers; these can provide sandbars and islands for nesting, and woodland over which the birds can catch insect prey. The breeding grounds and habitat are unknown, although river valleys in northern Thailand or southwestern China are possibilities. A claimed depiction of this species in a Chinese scroll painting initially appeared to support the possibility of the martin breeding in China. The bird in the painting had a similarly shaped head and bill, a white eye and a long tail, although it lacked the white rump, did not show the correct bill colour, and elongated the outer, rather than central, tail feathers. Painted before 1970, it pre-dated the publication of pictures of the Thai bird, so it must have been painted from life. It is now thought more likely that the scroll shows Oriental pratincoles (Glareola maldivarum). Cambodia and Burma have also been suggested as possible refuges for the martin, but there has also been speculation on whether it is migratory at all.