Description
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.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Costa Rica, Panama

View distribution map in BerkeleyMapper.

Due to the rarity of H. fimbrimembra, the original distribution was based solely on the type locality collected by Richard C. Taylor in the 1940's (Duellman 1970). The two specimens, one juvenile and one adult, were collected on the Caribbean slopes of Volcan Poas, Isla Bonita, Heredia Province, Costa Rica at an altitude of 1500 m (Duellman 1970). A tadpole collected by Norman J. Scott and Jay M. Savage in 1963 was found nearby at Cinchona, Canton Alajuela, Provincia de Alajuela, Costa Rica, at an elevation of 1360 m (Savage 1980). Two more specimens, a juvenile and an adult female, were reported by Hayes et al. (1986), extending the range 70 km west of Poas to the Monteverde Cloud Forest Reserve in the Cordillera de Tilaran, Provincia de Puntarenas, Costa Rica at 1550 m, and 25 km southeast on the southern, Pacific slopes of Cerro Turu in the Cordillera Central, Provincia de Heredia, Costa Rica at 1600 m, respectively. Craig Guyer collected two more adult specimens from Braulio Carrillo National Park, Costa Rica (Hayes et al. 1986). Finally, a collection from April 1982 warranted a 220 km (by air) range extension northwest to Panama, Provincia de Chiriqui, Distrito de Boquete, Cerro Horqueta, where the specimen was collected at an elevation between 1600-1700 m (Ibanez et al. 1991).

The habitat has been characterized, using the designations of Holdridge, as the Lower Montane Rainforest Lifezone, prominent with epiphytes and humid forest typically less than 20 m in height (Hayes et al. 1986). Individuals have been collected in the following situations: at night on a small plant bathed in the spray of a waterfall, during the day beneath the bark of a dead, standing tree, and in the late afternoon on an epiphyte 1.2 m above the ground (Taylor 1952; Duellman 1970; Hayes et al. 1986). The only observed tadpole was found in a small borrow-pit ditch (Hayes et al. 1986 personal communication with Norman Scott).

Life History, Abundance, Activity, and Special Behaviors
Extremely little information is known for H. fimbrimembra. Potentially, the presence of dermal fringes enables it to glide, similar to Eleutherodactylus coqui and members of the genus Rhacophorus. Gliding has never been observed in this species, although it has been observed in its close relative, Hyla miliaria (Duellman 1970). Observations of collected specimens seem to suggest nocturnal activity, and note its preference for moist retreats (Hayes et al. 1986; Duellman 1970). There is no information available to estimate abundance, suggesting perhaps that it is a rare or cryptic species.

Trends and Threats
Due to the extreme rarity of sightings, no demographic data is available for H. fimbrimembra, and thus its conservation status remains unknown.

Comments
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).

References

Duellman, W.E. (1970). The Hylid Frogs of Middle America. Monograph of the Museum of Natural History, University of Kansas.

Hayes, M.P., Pounds, J.A. and Robinson, D.C. (1986). ''The Fringe-limbed Tree Frog, Hyla fimbrimembra (Anura: Hylidae): new records from Costa Rica.'' Florida Scientist, 49(4), 193-198.

Ibáñez, R., Jaramillo, C.A., Solís, F.A., and Jaramillo, F.E. (1991). ''Hyla fimbrimembra (Fringe-limbed Tree Frog).'' Herpetological Review, 22(4), 133-134.

Savage, J. M., and Heyer, W. R. (1968). ''The tree-frogs (Family Hylidae) of Costa Rica: diagnosis and distribution.'' Revista de Biologia Tropical, 16(1), 1-127.

Savage, J.M. (1980). ''The tadpole of the Costa Rican Fringe-limbed Tree-frog, Hyla fimbrimembra.'' Proceedings of the Biological Society of Washington, 93(4), 1177-1183.

Taylor, E.H. (1948). "Two new hylid frogs from Costa Rica." Copeia, 1948, 233-238.

Taylor, E.H. (1952). "A review of the frogs and toads of Costa Rica." University of Kansas Science Bulletin, 35(5), 577-942.

Species Account Citation: AmphibiaWeb 2021 Ecnomiohyla fimbrimembra: Fringe-limbed Treefrog <https://amphibiaweb.org/species/796> University of California, Berkeley, CA, USA. Accessed Nov 23, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 23 Nov 2024.

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