Summary Our knowledge is the first report on karyotypic study of four toad species (genus Bufo) in Thailand namely; large-eared toad (Bufo macrotis Boulenger 1887), Indochinese dwarf toad (Bufo parvus Boulenger 1887), common Indian toad (Bufo melanostictus Schneider 1799) and river giant toad (Bufo asper Gravenhorst 1829). Blood samples were taken from 5 males and 5 females of each four toad species. After the standard whole blood T-lymphocyte culture in the presence of colchicine, the metaphase spreads were performed on microscopic slides and air-dried. Conventional staining, G-banding and C-banding techniques were applied to stain the chromosomes. The results indicated 2nϭ22 and fundamental number (NF) 44 in both male and female of four toad species. The autosomes of B. macrotis and B. melanostictus is being as 18 metacentric and 4 submetacentric chromosomes while B. parvus and B. asper is as 16 metacentric and 6 submetacentric chromosomes. Gbanding technique showed a B. melanostictus's constriction on short arm of Y chromosome (the largest chromosome) but did not show on X chromosome. C-banding technique demonstrated a dark band constriction on Y chromosome of B. melanostictus, the representative of constitutive heterochromatin. However, there is no dark band constriction on X chromosome. So, we conclude that the sex determination of B. melanostictus is XY system. Although we do not treat B. macrotis, B. parvus and B. asper with G-banding and C-banding technique, we also predict that those three species have the same sex determination as B. melanostictus. We extremely appreciate to public our present research, the first cytogenetic study of B. macrotis and B. asper.

Summary As endangered species in Thailand, the wild animal species of the common palm civet (Paradoxurus hermaphrodites), masked palm civet (Paguma larvata), large Indian civet (Viverra zibetha), large-spotted civet (Viverra megaspila), and binturong (Arctictis binturong) were selected for karyological study. Blood samples were taken from 1 male and 1 female of each species. After the standard whole blood lymphocyte culture in the presence of colchicine, the prometaphase spreads were performed on microscopic slides and air-dried. High resolution GTG-banding technique was applied to stain the chromosomes. The results showed that 2n (diploid) of Par. hermaphrodites, Pag. larvata, V. zibetha, V. megaspila and A. binturong were 42, 44, 38, 38, and 42, respectively. The autosomes presence of metacentric, submetacentric, acrocentric and telocentric autosomes were 6-10-14-10, 6-8-12-16, 8-6-18-4, 4-12-16-4 and 6-12-4-18, respectively. The X chromosome were submetacentric, submetacentric, metacentric, submetacentric and metacentric, and the Y chromosome were submetacentric, acrocentric, telocentric, telocentric and acrocentric chromosome, respectively. The numbers of bands in one set of prometaphase haploid chromosomes from the high resolution GTG-banding technique were 233, 262, 198, 222, and 247 bands, respectively and each chromosome pair could be clearly differentiated.

Summary Cytogenetics of banded palm civet (Hemigalus derbyanus) in Thailand was studied. Blood samples were taken from 2 males and 2 females then subjected to standard whole blood Tlymphocyte culture. The samples were harvested by colchicine-hypotonic-fixation-air-drying technique and followed by conventional staining, GTG-banding and high-resolution techniques with Giemsa's. The results showed diploid number as 2nϭ42, and fundamental number (NF) as 81 in both male and 82 in female. The autosomes consist of 10 large submetacentric, 12 large acrocentric, 4 medium submetacentric, 4 small metacentric, 8 small submetacentric and 2 small telocentric chromosomes. We found that nucleolar organizer regions (the representative of chromosome marker) locate on the long arms of a pair metacentric autosome 15. The X chromosome was a large acrocentric chromosome while the Y chromosome was the smallest telocentric chromosome. From GTG-banding and high-resolution techniques, the numbers of bands and locations in banded palm civet were 218 and 244, respectively. Each homologous chromosome pair appears clearly differentiated.