This species is endemic to Borneo, occurring in Kalimantan (Indonesia), Sabah, and Sarawak (Malaysia), between 200–1,300 m asl. It probably occurs more widely than current records suggest, especially in areas between known sites.
Habitat and Ecology
This species lives in the floor litter of closed-canopy montane and lowland forests. Specimens have been recorded from areas that have been severely logged. Breeding takes place in very small rain pools, and possibly in phytotelms.
There are no estimates of population size, although the species is reported to be abundant in some areas. In Sarawak, the species is not considered to be abundant (I. Das pers. comm. March 2018). Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
The principal threat to the species is rapid clear-cutting of lowland tropical rainforest in forest concession land and for oil palm plantations in Kalimantan and Sarawak (Indonesia Red List Assessment Workshop May 2017, I. Das pers. comm. March 2018). Some species of this genus use pitcher plants for breeding, and these plants can be collected by locals for ornamental purposes and are used to cook rice; however it is unknown whether this species uses pitcher plants in this manner (I. Das pers. comm. March 2018).
This species has been recorded from several protected areas. In Sabah, it occurs in Kinabalu National Park, Tawau Hills Park and Danum Valley Field Centre, Maliau Basin (Sabah Foundation), as well as, the Lipaso Forest Reserve, but this reserve is probably not being managed adequately for the purpose of biodiversity conservation (P. Yambun pers. comm. January 2018). It probably also occurs in Crocker Range National Park, however this requires confirmation (P. Yambun pers. comm. January 2018). In Sarawak, it occurs in Kubah National Park (I. Das pers. comm. March 2018). In Kalimantan, it occurs in Gunung Palung and Kayan Mentarang National Parks.
Effective preservation of lowland forest is needed to conserve this species because oil palm plantations are encroaching into protected areas in Kalimantan. Some oil palm companies and forestry companies designate High Conservation Value areas, which is required by some financial institutions providing loans. However, not all lenders require these areas to be set aside and the habitat within the HCVs could disappear if the lender or requirements change (Indonesia Red List Assessment Workshop May 2017). More effective protection and preservation of mid-elevation forests and riparian forest in the vicinity of Lipaso Forest Reserve in Sabah is essential (P. Yambun pers. comm. January 2018).
Further research on this species' distribution, population size and trends is recommended. Taxonomic work is required to be done on the whole genus to provide improved information for the reliable identification of these species (I. Das pers. comm. March 2018).
Red List Status
Least Concern (LC)
Listed as Least Concern in view of its relatively wide distribution, tolerance of a degree of habitat modification, and presumed large population.
This species may be a taxonomic complex and further work needs to be carried out (I. Das pers. comm. March 2018).
IUCN SSC Amphibian Specialist Group 2018. Kalophrynus heterochirus. The IUCN Red List of Threatened Species 2018: e.T57836A114919098. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T57836A114919098.en .Downloaded on 17 November 2018