This species is known from several localities on the islands of Mindanao, Basilan, and the Sulus, in the southern Philippines. It occurs from 0–500 m asl (A. Diesmos pers. comm. March 2018). It probably occurs more widely than current records suggest, especially in areas between known sites. Its extent of occurrence (EOO) is 23,320 km2 and all individuals are estimated to occur at four threat-defined locations.
Habitat and Ecology
This species inhabits and breeds in streams and quiet pools of water in undisturbed and disturbed lowland forests. Very little information is known about its ecology or habitat requirements. It is presumed to breed by larval development, as with other species in the genus (A. Diesmos pers. comm. March 2018).
It is a common species. Due to ongoing decline in the extent and quality of habitat on Mindanao, the population is suspected to be decreasing.
The major threat is the destruction and conversion of both lowland and montane rainforest habitat on Mindanao due to small-scale agricultural activities, large-scale oil palm plantations, wood collection for charcoal production, and expanding human settlements (Philippines Red List Assessment Workshop May 2017). There is also nickel, chromite, and gold mining, and limestone and marble quarrying in eastern Mindanao. In addition, the quality of its stream habitat is subject to pollution due to agricultural effluents, soil erosion, and mine-tailings (Philippines Red List Assessment Workshop May 2017). Civil unrest is still a problem on the islands of Jolo and Basilan, which has prevented any recent surveys to be carried out (A. Diesmos pers. comm. March 2018).
This species' range does include a few protected areas, such as Mount Malindang Natural Park.
The designation of remaining rainforests on the island of Mindanao as protected areas is a necessary conservation measure for this species.
More information is needed on this species' distribution, population status, ecology, and threats.
Red List Status
Listed as Near Threatened because although its extent of occurrence (EOO) is 23,320 km2, it occurs in four threat-defined locations and there is continuing decline in the extent and quality of its lowland forest habitat, thus making the species close to qualifying for Vulnerable under criterion B.
IUCN SSC Amphibian Specialist Group 2018. Occidozyga diminutiva. The IUCN Red List of Threatened Species 2018: e.T41225A58476592. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T41225A58476592.en .Downloaded on 19 January 2019