Pelophryne penrissenensis is a dwarf toad so far known only from the slopes of Gunung Penrissen.

Matsui et al. (2017) have described the species as 225–28 mm in males and 31 mm in females. As is typical for Pelophryne, webbing at fingers and toes is fleshy. Fingers and toes bear expanded discs, truncated in case of this species. Dorsum brown with lighter X-pattern. Ventral side cream. Abdomen with dark spots. Males bear madibular spines and have nuptial pads. Note that P. rhopophilia seems to be very similar to P. penrissenensis Both have the X-pattern on the back. Matsui et al. (2017) point out larger size and different ventral color pattern in P. penrissenensis. 

Reproductive mode and tadpoles are unknown.