Bufo parvus is a small toad, with females of this species typically being larger than the males. Females have a snout-vent length of 40-50 mm while the males reach a snout-vent length of 30-35 mm. This toad has a short snout. A supraorbital ridge and a pair of parietal ridges are present. The skin is wrinkled and bears tubercles or warts. No tubercles are present behind the parotoid gland. The toes are half-webbed. Adult B. parvus can be brown, black, or reddish in color while the juveniles are brown in color. Adults also generally have a pair of symmetrical black spots on the mid-back. Males usually have a reddish throat (Iskandar, 1998).
The tadpoles are small, with the tail usually no longer than double the head plus body length, and a denticle formula of I+1-1/III. Papillae are confined to the corner of the mouth, and the mouth is not adapted for stream-dwelling (Iskandar, 1998). Inthara et al. (2005; p. 78) provide a drawing of the larval mouthparts of Bufo parvus compared to eight other tadpole species of Thailand.
Bufo parvus is toxic, with skin extract doses of 100 mg/mouse causing locomotor difficulties, prostration convulsions, and death in 2 hours (Daly et al., 2004). This frog is very similar to Bornean populations of B. biporcatus in morphology and behavior (Inger et al., 1974). Bufo parvus can be distinguished by its smaller size and by the lack of tubercles behind the parotoid gland (present in B. biporcatus), as well as by having a pair of symmetrical black blotches on the back (absent in B. biporcatus) (Iskandar, 1998).
The species name uses the Latin word parvus, meaning small (Iskandar, 1998).
- Daly, J. W., Noimai, N., Kongkathip, B., Kongkathip, N., Wilham, J. M., Garraffo, H. M., Kaneko, T., Spande, T. F., Ninit, Y., Nabhitabhata, J., and Chan-Ard, T. (2004). ''Biologically active substances from amphibians: preliminary studies on anurans from twenty-one genera of Thailand.'' Toxicon, 44, 805-815.
- Inger, R. F., Voris, H. K., and Voris, H. H. (1974). ''Genetic variation and population ecology of some Southeast Asian frogs of the genus Bufo and Rana.'' Biochemical Genetics, 12(2), 121-145.
- Inthara, C., Lauhachinda, V., Nabhitabhata, J., Chuaynkorn, Y., and Kumtong, P. (2005). ''Mouth part structures and distribution of some tadpoles from Thailand.'' The Thailand Natural History Museum Journal, 1, 55-78.
- Iskandar, D. T. (1998). The Amphibians of Java and Bali. Research and Development Centre for Biology-LIPI, Bogor, Indonesia.