[1][4][3] Pelophryne murudensis is a comparatively large species within its genus: adult males measure 22–26 mm (0.9–1.0 in) in snout–vent length;[2] females are unknown.

A dusky brown or dark grey-brown preocular stripe runs from the nostrils to the eye, then along postocular region and broadening after the level of tympanum, and continuing along flanks, contrasting with the relatively lighter dorsum.

[4] The type series was collected from montane forest at elevations of 2,120 m (6,960 ft) above sea level.

The males were found calling from leaves up to three meters above the ground along forest trails.

This species is believed to be endemic to Mount Murud, which implies that its potential range is small, likely less than 5 km2.