Description
Head as broad as or broader than body, considerably wider than long; head width 38.4 to 42.2 (mean 40.20 per cent SVL; snout subacunimate in dorsal view, truncate in lateral profile; lips not flared; nostrils lateral, near tip of snout; length of eye slightly less than length of snout; interorbital space as broad as or slightly narrower than width of eyelid , width of eyelid 97.9 to 127.4 (mean 105.5) per cent interorbital distance; Tympanum round, poorly defined externally. Its upper and posterior edges usually partly concealed, 28.5 to 42.8 (mean 36.8) per cent length of eye; superatympanic fold absent; tongue large, ovoid, weakly notched posteriorly, posteriot one-halt to two-thirds free; choanae relatively small, situated lateally, completely visible when roof of mouth is is viewed from directly below; prevomerine dentigerous processes present, low, usually not obvious except in large specimens, situated mesiad and slightly posteriad from choanae, each bearing 2-4 teeth; males with relatively short vocal slits and large, external, subgular vocal sac.

Skin of dorsum and venter areolate, that of throat less areolate than that of rest of body; discoidal fold prominent; anal opening not modified; shank 46.3 to 53.8 (mean 48.1) percent SVL; ulnar tubercles not distinguishable; median and outer palmar tubercles broken up into flat supernumerary thenar tubercles; subarticular tubercles moderate-sized, distal subarticular tubercles of third and fourth fingers bifid; fingers lacking lateral fringes or webbing; digital tips expanded into round pads, those of outer fingers largest, each bearing circumferential groove; pads on outer fingers bear terminal papillae; first finger slightly shorter than second.

Tarsus and heel devoid of tubercles; inner metatarsal tubercle large, ovoid, not compressed, three to four times as large as round to ovoid outer metatarsal tubercle; plantar surface areolate, lacking defined supernumerary tubercles; subarticular tubercles of toe like those of fingers, distal tubercles bifid; digital tips expanded,bearing circumferential groove, second, third and fourth toes bearing distal papillae; toes lacking webbing or lateral fringes.

Dorsum cream with or without pale metallic green washand spotted or reticulated with reddish brown or uniform reddish brown; posterior surfaces of thighs and ventral surfaces colorless or pale cream; limbs spotted with reddish brown or not; inner digits colorless, outer digits pale cream to reddish-brown.
The coloration of living specimens is complex owing to complex metachrosis. The color of one indidvidual can change so as to cover the spectrum of color variation of the species. The dorsum and limbs are uniform creamy yellow, the flanks pale yellow, the venter and posterior surfaces of thighs white, and hands and feet pale orange. The throat of males is faintly washed with yellow. The ground color changes through pale reddish-bronze to reddish-brown. Accompanying this change, the hands and feet change from pale orange to yellow. The dorsum is usually spotted with reddish-brown although frogs in the lightest color phase (uniform creamy yellow) may lack spots. Both the tops and bottoms of hands and feet are pale orange to yellow and this color does not grade into the color of the forearm or tarsus. The iris apparently black (Lynch 1970).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia, Ecuador

View distribution map in BerkeleyMapper.

This species occurs at elevations of 50-1970m from Southwestern Departamento Antioquia, Columbia, to Provincia Guayas, Ecuador. Twenty of the 25 Ecuadorian localities for this species are below 1000m, where it seems to be far more abundant than it is at higher elevations. The species is absent from the drier regions of southwestern Ecuador, but one of the syntypes supposedly originated from Chimbo, Provincia Guayas, in the dry subtropical regime. Six Ecuadorian localities are in the humid tropical regime, whereas 18 are in the humid subtropical regime (Lynch and Duellman 1997).

Life History, Abundance, Activity, and Special Behaviors
During the day, these small frogs take shelter in the axils of leafs of bromeliads and elephant ear plants. At night, they are active on native and cultivated vegetation, usually no more than 1.5m above the ground. During 1977-1998 John D. Lynch marked large numbers of E. chalceus in a banana grove at the edge of Santo Domingo de los Colorados, Provincia Pichincha. As many as 30 individuals were encountered in a single evening on herbacioous vegetation in the banana grove, as well as on the leaves of the banana plants. The ease of collecting in the banana grove may contribute to John D. Lynch' impression that E. chalceus was more abundant in the banana grove than in primary forest 1or 2 km away. Pristimantis chalceus is often found on vegetation besides streams, but the observation of the species there probably reflects collectors' preferences for streams rather than that of the frogs, which are also abundant in the forest away from streams. Males were found calling in May at Maldonado, Provincia Catchi, and in June at Santo Domingo de los Colorados, Provincia Pichincha (Lynch and Duellman 1997).

Comments
This species was found to be abundant in banana groves, and seemed to be more abundant there than in the nearby primary forest. This may be an artifact of observation, however (see "Life History, Abundance, Activity, and Special Behaviors").

References

Lynch, J. D. and Duellman, W.E. (1997). Frogs of the Genus Eleutherodactylus in Western Ecuador. The University of Kansas Natural History Museum, Lawrence, Kansas.

Lynch, J.D. (1971). ''Redescriptions of three little-known Eleutherodactylus from northwestern Ecuador (Amphibia: Leptodactylidae).'' Transactions of the Kansas Academy of Science, 73(2), 169-180.

Species Account Citation: AmphibiaWeb 2008 Pristimantis chalceus <https://amphibiaweb.org/species/2843> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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