This species is known only from Danum Valley Conservation Area and Tawau Hills National Park in Sabah (I. Das unpubl. data March 2018, Haas et al. 2018) and Sungai Pesu in Sarawak in Borneo, Malaysia. It has been recorded at elevations up to 300 m asl. Its extent of occurrence (EOO) is 28,765 km2 and all individuals occur in two threat-defined locations. There is no suitable habitat left within the Sungai Pesu area so it not likely to be more widespread within this area in Sarawak, however it may occur more widely in Sabah (I. Das pers. comm. March 2018).
Habitat and Ecology
This species has been recorded only in primary, lowland rainforest in riparian regions. Males call from leaves or twigs of small trees along stream banks at heights of up to 4 m off the ground (Inger et al. 2017). Breeding is by direct development, and females have non-pigmented eggs (Inger et al. 2017). Males are 21-23 mm in size, whereas females are 24-25 mm (Inger et al. 2017). The call of this species is unknown (Inger et al. 2017).
In Sabah, this species is considered to be rare (I. Das pers. comm. March 2018). From multiple trips in 2004 and 2010, only one or two individuals were found within 10-15 days of searching per trip (I. Das pers. comm. March 2018). Due to ongoing decline in the extent and quality of habitat, the population is suspected to be decreasing.
In Sabah, the species is not threatened by any activities as the only known subpopulations occurs within two well-protected and well-managed area (P. Yambun pers. comm. January 2018, I. Das pers. comm. March 2018). The clear-cutting of lowland forest in Sarawak is the most serious threat to this species at present.
This species has been recorded in Danum Valley Conservation Area and Tawau Hills National Park in Sabah.
More effective protection of remaining lowland forests in Borneo is essential.
More information is needed about the species' population status, distribution, natural history, and threats.
Red List Status
Listed as Near Threatened, because although this species has an extent of occurrence (EOO) of 28,765 km2, it occurs in three threat-defined locations and there is continuing decline in the extent and quality of its lowland forest habitat in Malaysian Borneo, thus making the species close to qualifying for Vulnerable under criterion B.
IUCN SSC Amphibian Specialist Group 2018. Philautus disgregus. The IUCN Red List of Threatened Species 2018: e.T58836A123693522. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T58836A123693522.en .Downloaded on 20 January 2019