This species is endemic to Panay Island in the Philippines (Siler et al. 2007). It was previously known only from its type locality at 180–300 m asl on Mount Lihidan in the Municipality of Pandan in Antique Province (Siler et al. 2007). However, further work has extended the range on the northwest Panay peninsula and it is now also known from several localities in Antique and Aklan Provinces, and the northern part of the Central Panay Mountain Range (Antique Province) (Gaulke 2011). The extent of occurrence (EOO) has therefore increased from 11 km2 to 507 km2 and it is considered to occur at two threat-defined locations.
Habitat and Ecology
The species is a karst forest obligate. It is suspected that, of the main factors needed for this species to survive in these karst forests, moisture content within the forest and rocky crevices is critical (C. Siler pers. comm.). Males call from either the top of rock outcroppings or from within crevices in the rock formations (Siler et al. 2007). The species appears to be adaptable to a certain extent, as the type locality contains secondary-growth forest, but it is not clear whether or not it can tolerate complete opening up of its habitat. As the forest gets more heavily destroyed, the karst patches will eventually become more arid and possibly less suitable for this species (C. Siler pers. comm.). It is presumed to breed by direct development without dependence of water.
The species is generally uncommon within its range (Gaulke 2011), but has been observed to be quite common during periods of heavy rain in the region. It is believed that this species maintains healthy subpopulations in the karst forests of northwestern Panay. However, due to ongoing decline in the quality and extent of its habitat, the population is suspected to be decreasing.
There is widespread forest destruction at its type locality due to expanding local agriculture and nearly all surrounding soil-dominated habitat around karst patches on Panay has been heavily disturbed by farming (Siler et al. 2007, C. Siler pers. comm. 2008). However, the habitat is protected to some extent from agricultural expansion as it is very difficult to farm on the very rocky terrain, which may provide some protection for this unique forest microhabitat (C. Siler pers. comm. 2008). Additional threats, include the degradation of the forest for the harvesting of non-timber products (Gaulke 2011) and some limestone mining and quarrying is occurring within the karst formation on this island, which presents a direct threat to the habitat of this species (C. Siler pers. comm. 2008).
The species occurs within the boundaries of the Northwest Panay Peninsula Natural Park, which offers a relatively good level of protection and has slowed the habitat loss there.
Urgent measures are needed to conserve forest on limestone karst in northwestern Panay.
Surveys for this species in karst forest habitats should be conducted across Panay Island in the rainy season.
Red List Status
Data Deficient (DD)
Listed as Endangered because of its extent of occurrence (EOO) of 507 km2, it occurs in two threat-defined locations, and there is continuing decline in the extent and quality of its habitat on Panay Island in the Philippines.
The coordinates listed in Siler et al. (2007) for this species' type locality were found to be inaccurate and this has been corrected in the distribution map (Philippines Red List Assessment Workshop May 2017).
IUCN SSC Amphibian Specialist Group 2018. Platymantis paengi. The IUCN Red List of Threatened Species 2018: e.T135858A114723984. http://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T135858A114723984.en .Downloaded on 18 December 2018