Hemicypris ovata Sars, 1903

(Fig. 5 C)

This species was described by Sars (1903) based on specimens from Sumatra, Indonesia and later redescribed by Victor & Fernando (1981) based on type material and additional specimens from the Philippines. There are several differences between the drawings made by Sars and those of Victor & Fernando. The morphology of the Thai specimens is more similar to Victor & Fernando’s drawings. The present record is the first for Thailand and it is the third Hemicypris species reported from the country, after H. mizunoi Okubo, 1990 and H. reticulata (Klie, 1930) (see Savatenalinton & Martens 2008). It was found in 7 localities in the present study: 4 small oxbow lakes and 3 stations of the Chi River itself. Only females were found with a total of 12 specimens. The species occurred in Thai localities in water temperatures of 26.3–33.9 ºC, a DO of 2.71–5.80 mg /L and a pH of 6.4–7.2.