Adult: Species description based on Savage (2002). A small frog (males to 19 mm, females to 25 mm). Dorsal: Dorsal coloration is pale brown or yellow, with some pink undertones. A slightly darker W-shaped patch is often present just behind the head. Other individuals have a single middorsal stripe or parallel dorsolateral stripes. The thighs are barred. The dorsal skin is smooth. Ventral: The ventral surface is yellow with some dark specks. Distinguishing characteristics: Pristimantis ridens has a characteristic dark bar just above the tympanum. Eye: The upper half of the iris is beige and the lower half is coppery.
Habitat: Lowland, premontane and lower montane forest to 1600 m. Ecology: This species is fairly common in premontane habitat (Savage 2002). It may be found on low vegetation at night or hiding in the leaf litter during the day (Savage 2002, Lieberman 1986). Call: A short trill (Ibanez, Rand and Jaramillo 1999). Type locality: St. Juan River, Nicaragua Diet: The diet consists of a variety of small arthropods, predominantly spiders and ants (Lieberman 1986).
Diagnostic description: The legs lacking webbing. Ll finger is longer than l, lll and lV and fingers have clearly expanded discs. The heel is smooth or with a few small tubers, the same size as other scattered tubercles on the lower limb. The groin and the anterior surface of the thigh lack of contrasting light and dark, or some other design spots. The discs have bearings and round shields. The upper lid has one or more large and sharp supraocular tubercles. The anterior and posterior surfaces of the thigh, calf and feet are red in live specimens. The back is not green in life.
Adult males lack nuptial pads, but have vocal slits.
The maximum standard length in males is 19 mm. and 25 mm. in females.
Habitat: Premontane live in rainforests. The species is active in litter during the day and at night is located in vegetation up to a meter from the ground. We have found them in bromeliads.
Reproduction: Eggs laid on the floor have direct development.
Food: They feed on a variety of arthropods: Formicidae, other Hymenoptera, Coleoptera larvae and adults, Homoptera and isopods.
Behavior: They are diurnal and nocturnal, and they are arboreal.
Distribution in Costa Rica: In wetlands, lower and middle of the Atlantic slope, center and south of the Pacific slope, marginally in the mountain passes of the Cordillera de Guanacaste and Tilarán between 15 and 1,600 m elevation (Savage 2002).
Distribution outside Costa Rica: They are in the Caribbean lowlands of eastern Honduras, Nicaragua extreme, Costa Rica and Panama; premontane evergreen forests in both the Caribbean slope and the Pacific of Costa Rica and Panama; in the lowlands of the southwest, and the evergreen forests of the Pacific slope of Panama, western Colombia and northwestern Ecuador. It is located between 15 and 1200 m.