Additions to the rotifer fauna of south-east Asia: New and rare species from north-east Thailand

Ninety-three freshwater habitats in the north-eastern part of Thailand were surveyed for rotifers during March-October 1993. Two hundred species were identified, 120 of which are new to Thailand. Brachionus africanus Segers, B. lyratus Shephard and Trichocerca hollaerti De Smet are new to Asia. Brachionus niwati n.sp. is described and figured. Brachionus donneri Brehm, Keratella edmondsoni (Ahlstrom) and Lecane blachei Berzins, endemic to south and southeast Asia, were found also. Comments are presented on some insufficiently known taxa. Of special zoogeographic interest is the record of several species previously considered endemic to Australia. An attempt is made to characterise the Thai rotifer fauna in the light of recent developments in rotifer zoogeography.