Comprehensive DescriptionRead full entry
Distinguished from all other Costa Rican hylids, with the exception of Hyla miliaria, by the presence of dermal fringes along the posteroventral margins of the limbs (Savage and Heyer 1968). It differs from H. miliaria and all other fringe-limbed hylids in having integumentary-cranial co-ossification (Duellman 1970). Other important features include a dermal fold present on the head, running from the orbit towards the jaw angle, then curving posteriorly to stop above the insertion of the arm. The upper edge of the tympanum is obscured by this fold, but is otherwise distinct and slightly smaller in size than the eye. Small, granular anal folds are present, extending ventrolaterally, the hands are 2/3 webbed and the fingers bear large, blue-black discs, while the toes bear smaller discs, and the feet are 3/4 webbed. The snout is acutely rounded in dorsal outline, and in lateral profile sloped steeply from nostril to lips, and the head is slightly wider than the body. The canthus is rounded but not elevated (Duellman 1970). Recorded measurements ranged from 71.0 to 86.5 mm for female adults and 30.5 to 47.5 for juvenile females (Duellman 1970; Hayes et al. 1986).
Taylor (1948) describes the adult coloration in life as uniformly lavender-brown, the jaw edge blue-black, the upper lip edged by black, throat yellowish and reticulated in purple, undersides of hands and feet lavender, upper limb surfaces faintly barred, and venter marked with cream . The only other adult was described as "yellowish-white," while a transitional juvenile form was described as a mixture of brown, yellow, and green in a lichen-like pattern, displaying color phases (Hayes et al. 1986). In this juvenile, the reticulum of green and brown expands from the lighter to darker color phase, such that the frog ranges from yellow-cream, to green and lichen-like. The iris is red-orange, but may undergo ontogenetic change, and the pupil is horizontal and asymmetrically diamond-shaped in bright light (Hayes et al. 1986). Additionally, this individual possesses a thin, white line running transversely above the vent, and guanophores in the anal folds, limb fringes, on the heel and on the tibiae. The other collected juvenile was noted to vary from the adult in having more conspicuous bands on the limbs, small dark flecks on the flanks, pale colored edges on the upper lip and chin, less pustular skin, and less skull co-ossification (Duellman 1970).
The tadpole of H. fimbrimembra is notable for its tuberculate flanks, small labial disk, and long tail (approximately 77% of its total length). The anus is dextral, the spiracle is sinistral and located below the level of the eye, and the denticles are arranged in two upper and three lower rows. The oral disc is complete, directed ventrally, and not indented laterally. The caudal fin extends as a low ridge on the body, nearly to the spiracle, the nostrils are directed anteriolaterally, and the eyes are directed laterally (entire tadpole diagnosis taken from Savage 1980).
No call has been described for this species.
For a summary of name history, and the substitution of Hyla richardtaylori with Hyla fimbrimembra, refer to Duellman (1970).
A Spanish-language species account can be found at the website of Instituto Nacional de Biodiversidad (INBio).