Aquatic nematodes from Ethiopia IX - One new and three known species of Dorylaimidae, Mononchus truncatus Bastian, 1865, and Diploscapter coronatus (Cobb, 1893) Cobb, 1913 (Nematoda)

Laimydorus ritae n. sp., Laimydorus pseudostagnalis, Dorylaimus stagnalis, Ischiodorylaimus ugandanus, Mononchus truncatus and Diploscapter coronatus are described from sediment samples of Lake Tana, Ethiopia. Laimydorus ritae n. sp. is identified by its short odontostyle (16-18 mu m), a value of 1.4 for the ratio 'odontostyle L/lip region width', a lip region offset by depression, an anteriorly situated longitudinal vulva, females with long tail (328-392 mu m), non-hamate terminus and presence of males. Detailed descriptions of the remaining five species with scanning electron microscopic pictures of L. pseudostagnalis are also provided. I. ugandanus is reported here for the first time out of its type locality, Uganda.