Kalophrynus yongi

Adult males measure 29–31 mm (1.1–1.2 in) in snout–vent length; the size of females is unknown. The overall appearance is stocky. The head is triangular, wider than it is long. The snout is obtusely pointed in dorsal view and truncate in profile. The canthus rostralis is distinct, as is the tympanum. The forelimbs are comparatively long and very stout; the fingers have rounded tips and slight basal webbing. The hind limbs are moderately long; the toes have rounded tips and poorly developed webbing. The dorsal ground color varies from light orange brown to dark chocolate brown. There are obscure dark markings. The venter is dirty cream, dusted with brown on the throat. Males have a single subgular vocal sac.^[2]

The male advertisement call is an intermittently emitted, soft "ting".^[2]

The type series was collected from a mossy cloud forest at elevations of 1,954–1,991 m (6,411–6,532 ft) above sea level.^[1][2] Adults are camouflaged and burrow into mosses, making them difficult to find.^[1] The diet includes spiders, grasshoppers, and weevils.^[2] Eggs and tadpoles have been found in a large cup of the pitcher plant Nepenthes macfarlanei, and tadpoles in a water-filled tree stump.^[1][2]

Suitable mossy forests are only found on the top of the mountain and the species is likely to be a micro-endemic, not to be found more widely. The habitat is threatened by tourist activities (hiking, expanding tourist facilities). Moreover, there is illegal collection of slipper orchids that could disturb the habitat. The population occurs within the Gunung Brinchang Forest Reserve.^[1]