Trachycephalus coriaceus (previously Phrynohyas coriacea) is a relatively large tree frog. In the lowland rainforest of southeastern Peru, Duellman (2005) reported a snout-vent-length ranging from 52.0 - 59.5 mm for males (with an average of 55.73 +/- 2.33 mm) and 52.9 - 64.8 mm for females (with an average of 58.55 +/- 3.39 mm). The head is broad, roughly the same width as the body, and the snout is short and round on both dorsal view and profile. The tympanum is ¾ the size of the eye and the thick supratympanic fold covers its upper edge. The dorsal skin is smooth, glandular, and thick. The ventral skin is areolate. Fingers and toes have round terminal discs and are relatively short. Fingers are ½ webbed while toes are ¾ webbed. Males have dark brown nuptial excrescences and paired lateral vocal sacks can be found posterior to the tympanum. Trachycephalus coriaceus tadpoles have an elongated, elliptical body that is widest just posterior to the eyes and throughout the midlength. The snout is round in dorsal view. When viewed in profile, the snout rounds off to a blunt tip anteroventrally. The eyes are positioned laterally. Infraorbital and supraorbital neuromast rows are conspicuous. The spiracle is on the left side of the body, and is completely attached to the body wall. The vent tube is dextral, just below the ventral fin. The caudal musculature is the same height throughout the anterior one-third of the tail length and tapers off into a thin tip towards the end. At the beginning of metamorphosis, the color of the limbs and the dorsum of the body are a pale green while the venter is a creamy white. The iris is a light orange. Metamorph individuals have brown dorsum with darker brown patterns (Duellman, 2005).
This species bears lateral vocal sacs and red webbing. There are only two other treefrogs found in Madre de Dios that have red webbing: Hyla geographica (now Hypsiboas geographicus; Claudia Azevedo-Ramos et al. 2010) and Hyla triangulum. Both of these species only overlap with a fraction of T. coriaecus' range. Hypsiboas geographicus has reticulated lower eyelids and calcars on the heels while H. triangulum is far smaller and has thin dorsal skin that differ the two species from T. coriaceus (Duellman 2005).
In life, the dorsum and flanks of the female are mostly composed of shades of brown, including reddish brown and grayish tan. In some individuals, the dorsum can have distinct, peculiar patterning: a large, brown rectangular shaped blotch that extends from the upper eyelids to the lower sacral region. and another smaller, horizontal, rectangular blotch below the sacrum. These dorsal markings are enclosed by narrow black and pale cream outlines. A black spot can be found posterior to the tympanum and below the supratympanic fold. The ventral surfaces of the shanks, the webbing of hands and feet, the anterior and posterior surfaces of the thighs, and inner surfaces of the feet are all red. The throat, belly, and sides are creamy yellow. The eyes are pale-orange with a metallic luster. When preserved, the dorsal markings may or may not be present. The species appears washed away, with the dorsal side being a homogenous brown and the ventral a dull tan or cream (Duellman 2005).
Tadpole body coloration changes from black to a dull brown during tadpole development. Specifically, both the dorsal and the sides of the body are colored dark brown to black while the ventral side is a contrasting silvery white. The caudal musculature is the same color as the dorsal side with two pale, broad lines running down the side, narrowing and converging distally. The fins are light grey. After preservation, the body becomes tan. There is an area above the snout that is a diffused brown. Posterior to the orbit is a brown blotch while below the orbit is a brown crescent-shape spot. The fins are translucent. The dorsal and ventral sides of the caudal musculature are dark brown while the rest of the caudal musculature is a creamy tan (Duellman 2005).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Bolivia, Brazil, Ecuador, Guyana, Peru, Suriname
Trachycephalus coriaceus is found in the Madre de Dios region in Peru, bordering Brazil and Bolivia. It is also found in Brazil, Bolivia, Ecuador, French Guiana, Guyana, and Suriname. Individuals are mainly found inhabiting inundated (flooded) forests, but may also be found in camp clearings and terra firma (“solid earth” or un-flooded) forest (Angulo et al. 2010).
Life History, Abundance, Activity, and Special Behaviors
This species is arboreal and nocturnal, and has a sit-and-wait foraging strategy (Duellman 2005). This species has been known to exhibit a defensive behavior that involves inflating itself to appear larger than it really is. This larger size may also make the individual more difficult to consume. In addition, this inflation emphasizes the two black spots on the flanks, posterior to the tympanum by making them visible from the front. However, these two defensive mechanisms, the puffing up of the body and the flash coloration, have not been observed as a response to a predator confrontation, but only seen when the individual is handled by a human (De la Riva 1994).
Most individuals congregate at permanent and temporary pools for breeding. During the breeding season, males exhibit a loud growl as an advertisement call while floating on the water and fully inflated. When inflated the paired lateral vocal sacs of the male inflate upward and over the head, nearly touching. Females oviposit eggs in a surface film on the water (Duellman 2005).
Trends and Threats
The species as a whole is probably not threatened. However, it is likely that local populations are threatened by deforestation (Angulo et al. 2010).
Relation to Humans
Cashinahua Indians (Balta, Departamento Ucayali) and the Achuar Indians in Ecuador are known to consume this species. Additional research is required in order to determine if this species is exploited as a source of protein in other locations (Angulo et al. 2010).
Possible reasons for amphibian decline
General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intentional mortality (over-harvesting, pet trade or collecting)
There has been a recent taxonomic change for this species: it was previously known as Phrynohyas coriacea (Angulo et al. 2010).
Angulo, A., Reynolds, R., Coloma, L. A., Santiago, R. (2010). Trachycephalus coriaceus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org. Downloaded on 19 February 2013.
Azevedo-Ramos, C., La Marca, E., Coloma, L. A., Ron, S., Hardy, J. (2010). Hypsiboas geographicus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. . Downloaded on 19 February 2013
De la Riva, I. (1994). ''An undescribed defensive mechanism in the neotropical hylid frog Phrynohyas coriacea.'' Amphibia-Reptilia, 15(2), 226-227.
Duellman, W.E. (2005). Cusco Amazónico: The Lives of Amphibians and Reptiles in an Amazonian Rainforest. Comstock Pub. Associates, Ithaca.
Originally submitted by: Adolfo Ivan Gomez (first posted 2013-02-19)
Edited by: Ann T. Chang & Rudolf von May (2013-03-08)
Species Account Citation: AmphibiaWeb 2013 Trachycephalus coriaceus: Surinam Goldeneye Tree Frog <https://amphibiaweb.org/species/1021> University of California, Berkeley, CA, USA. Accessed May 31, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 31 May 2023.
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