This species is known from the type locality, the island of Koh Chang, Trat Province, in south-east Thailand, and is also found in the Cardamom Mountains of Cambodia (Ohler, Swan and Daltry 2002). It has been recorded below 800m asl.
Habitat and Ecology
This species is known from evergreen forest on the lower slopes of the mountains as well as in gallery forest, and also heavily disturbed areas and forest edge habitat. Males were heard calling from near streams where they were concealed in undergrowth. The exact breeding habits are unknown.
It is common in Koh Chang (T. Chan-ard pers. comm.) and also in the Cardamom Mountains at lower altitudes (S. Swan pers. comm.).
A threat to this species is probably the clear-cutting of forests although it appears to also inhabit disturbed areas.
Its range includes Ko Chang National Park, and several protected areas within the Cardamom Mountains of Cambodia. Surveys to determine the species' range, habitat requirements and population status are needed.
This species was removed from synonymy of Hylarana nigrovitatta without comment by Dubois (1992), and treated as a valid species by Inger, Orlov and Darevsky (1999). It was regarded as a synonym of H. nigrovittata by Matsui et al. (2001) but treated as a valid species by Ohler, Swan and Daltry (2002) and hence here also.
Peter Paul van Dijk, Steven Swan 2004. Hylarana mortenseni. In: IUCN 2014