A taxonomic account of Oryzias minutillus, O. mekongensis, O. dancena, and O. javanicus from Thailand, O. celebensis from Indonesia and O. latipes from Japan are redescribed. Six distinct species are recognized. Keys, descriptions and illustrations of the species are presented. Morphological differences between and within all six species are clarified. Twenty-two morphometric characters and ten meristic characters were examined, and 14 morphometric and nine meristic characters were found to differ amongst the six species. Anal-fin ray numbers of O. cellebensis, O. javanicus, O. dancena, O. minutillus, O. latipes and O. mekongensis were 22, 23, 24, 19, 18 and 15, respectively. These differences suggest that the six species may be reproductively isolated from each other.
KEY WORDS: Oryzias, Revision, Morphological difference, Cluster analysis
FIGURE 8. Geographical distribution of the Oryzias species: O. dancena , O. javanicus, O. mekongensis, O. minutillus, O. celebensis (▲) and O. latipes.
FIGURE 2. Illustration of Oryzias javanicus (Bleeker) based on material specimens of NIFI 3218; A, adult male and B, adult female, from Phuket province, Peninsular Thailand. Bar indicate 5 m
FIGURE 3. Illustration of Oryzias dancena (Hamilton), based on material specimens, NIFI 3236; A, adult male and B, adult female, from Ranong province, Peninsular Thailand. Bar indicate 5 mm.
FIGURE 4. Illustration of Oryzias minutillus Smith, 1945, based on material specimens, NIFI 3215; A, adult male and B, adult female, from Ban Tad, Udon Thani province, the Mekong region. Bar indicate 3 mm.
FIGURE 5. Illustration of Oryzias mekongensis Uwa and Magtoon, 1986, based on material specimens, NIFI 3209; A, adult male and B, adult female, from Udon Thani, province, Peninsular region. Bar indicate 3 mm.
FIGURE 6. Illustration of Oryzias latipes (Temminck & Schlegel 1846), NIFI 3424, A, adult male and B, adult female, from Gifu Prefecture, Japan. Bar indicate 5 mm.
FIGURE 7. Illustration of Oryzias celebensis (Weber, 1894), base on material specimens, NIFI 3237: A, adult male and B, adult female, from Sulawesi, Indonesia. Bar indicate 5 mm.
Magtoon, W. and Termvidchakorn, A. 2009. A revised taxonomic Account of ricefish Oryzias (Beloniformes; Adrianichyidae), in Thailand, Indonesia and Japan. The Natural History Journal of Chulalongkhorn University, 9: 35-68.: http://www.biology.sc.chula.ac.th/NHJCU/9-1/4.%20Magtoon%20Proof5.2.pdf
Termvidchakorn, A. and Magtoon, W. 2008. Development and identiﬁcation of the riceﬁsh Oryzias in Thailand. ScienceAsia. 34: 416–423. doi: 10.2306/scienceasia1513-1874.2008.34.416 / http://www.scienceasia.org/2008.34.n4/scias34_416.pdf