Pristimantis stipa is a robust bodied frog with a snout-vent-length ranging from 15.6-24.4 mm for males, and 35.1 mm for females. The head is narrow and wider than
Pristimantis stipa is a robust bodied frog with a snout-vent-length ranging from 15.6-24.4 mm for males, and 35.1 mm for females. The head is narrow and wider than it is long, though it is not as wide as the body. The snout is short and round at both lateral and dorsal views. The canthus rostralis (or rostral crest) appears somewhat curved in profile view but straight at dorsal view. The tympanic annulus, though present, is weakly defined. Tympanic membrane is present and distinct. A large thick fold over the tympanum partially obscures its edges on the posterodorsal sides. The tympanic membrane diameter is 35.8% that of the eye diameter. Upper eyelid lacks nodules. The dorsum is fairly smooth. The ventral side of the thighs, belly, chest, and throat are not as smooth as the dorsal surface and are a little more granular. The dorsolateral fold is distinct, thick, and discontinuous. The hind limbs are slender. The heel and the outer surfaces of the tarsus lack tubercles. A short, inner-tarsal ridge is present. The inner metatarsal is prominent, elliptical and twice as large as than those in the low tubercles. The toes lack lateral fringes and webbing. Both fingers and toes have narrow discs with rounded tips and the discs on the toes lack circumferential grooves. The relative toe lengths are: 1<2<3>5<4. Toe III is a little bit longer than toe V. Vocal slits are absent on males. Males also have nuptial pads on dorsal and medial surfaces of the thumb (Venegas and Duellman 2012).
The following features differentiate P. stipa from the rest of the species in Pristimantis, including the 15 assigned to the P. orestes group (with the exception of P. simonsii): P. stipa has a smooth dorsum, the discs on the fingers and toes are narrow and lack marginal grooves, and ulnar nodules form a low fold. P. stipa can be easily distinguished from P. simonsii by the following characteristics: prominent dentigerous processes of vomers (which are absent in P. simonsii), both the tympanic annuls and tympanic membrane are distinct (they are absent in P. simonsii), and toe V is just a bit shorter than toe III (in P. stipa, toe V and toe III are just about the same length). Because P. stipa lacks marginal grooves on the discs of the toes and fingers, it can be confused with Phrynopus, of which one species, P. thompsoni, is also found. However, P. thompsoni has rows of small swellings on the dorsum, both the tympanic membrane and the tympanic annulus are absent, fingers I and II are the same length, and the venter is tan with lighter brown spots (Venegas and Duellman 2012).
Coloration in life: In the female holotype, the dorsum is homogenously brown. The groin, posterior and anterior surfaces of the thighs, and dorsal surfaces of the feet are a darker shade of brown decorated with dull white blotches. The venter is a dark brown with white spots. The iris is grayish-white with a network of thin, brown lines. Males have brownish cream mottling on their throats while the same mottling on females is white (Venegas and Duellman 2012).
Coloration in preservation: 