This species is known from a single locality in the Khao Chong Mountains of Peninsular Thailand. It presumably occurs more widely within these mountains, as has been mapped. The type locality is at an elevation of 300m asl. Some populations in Peninsular Thailand currently assigned to Ansonia malayana might in fact belong to this species (L. Grismer pers. comm.).
Habitat and Ecology
It is restricted to lowland primary tropical moist forest. It is a stream-breeding species.
It is apparently uncommon. A pair was collected in 1979, and a further five individuals have been collected since (Kiew 1984b, Matsui, Nabhitabhata and Panha 1998).
The habitat of this species appears to be reasonably well protected at present, and there are currently no major threats. However, given its restricted range, it is potentially at risk from stochastic events and pollution from adjacent tourist sites.
The known range is entirely within the Khao Chong Mountains protected area. The population status of this species requires careful monitoring, given that it is known only from a single location.
Peter Paul van Dijk, Jeet Sukumaran, Norsham Yaakob, Leong Tzi Ming, Yodchaiy Chuaynkern 2004. Ansonia siamensis. In: IUCN 2014