Adults vary in size with males ranging from 53-56 mm and females ranging from 60-66 mm. Males are more brightly colored, though both sexes display diurnal color variation. At night, the frogs are a dark green while during the day they turn an emerald green with two iridescent copper bands. An uneven yellow coloration has also been reported on the male vocal sac. The eyes have a vertical, elliptical pupil. Tadpoles of Hylorina sylvatica are light brown on top and dark brown below. They can be further distinguished by a dark ring around the nostrils and a rhomboidal spot between the eyes.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Argentina, Chile
Hylorina sylvatica is endemic to the austral forests of Chile and Argentina with a narrow range on the eastern Andean slopes. In Chile, this species ranges from the western slope of the Cordillera de Nahuelbuta to Laguna San Rafael. In Argentina, these frogs have been found in a few locations at Nahuel Huapi National Park (southern Neuquén Province and northwestern Río Negro Province) and at Los Alerces National Park (northern Chubut Province). Individuals have often been found in or near forests dominated by Nothofagus. They are found in the darker areas of the understory (under fallen trunks, hidden in leaf litter, etc.), but, during the breeding season, they concentrate in open areas next to lakes and lagoons.
Life History, Abundance, Activity, and Special Behaviors
Breeding and oviposition occur around December or January (summer). Males can be found calling around the borders of water bodies, slightly submerged. However, they are also found some distance from the water’s edge, concealed within clumps of ferns. The male and female join in axillary amplexus.
Eggs are submerged near the border of the water body. Initially, they are independent but after the first few days they clump together, held in a gelatinous mass. Larvae emerge after approximately ten days. Metamorphosis occurs at the end of ~1 year.
Trends and Threats
No specific threats have been described, though their small numbers make this species particularly vulnerable to environmental changes such as habitat destruction, climate change, etc.
Possible reasons for amphibian decline
General habitat alteration and loss
Climate change, increased UVB or increased sensitivity to it, etc.
Barrio, A. (1967). ''Observaciones etoecologicas sobre Hylorina sylvatica Bell (Anura, Leptodactylidae).'' Physis, 27(74), 153-7.
Coll, M.S.M., Ochoa, M.L., and Úbeda, C.A. (2002). ''Hylorina sylvatica: Sighting account.'' Herpetological Review, 33(1), 61-2.
Formas, J.R. and Pugín, E. (1978). ''Tadpoles of Hylorina sylvatica, Eupsophus vittatus, and Bufo rubropunctatus in southern Chile.'' Herpetologica, 34(4), 355-8.
Originally submitted by: Christopher Streeter (first posted 2003-01-09)
Edited by: Meredith Mahoney and Christopher Streeter (2003-02-03)
Species Account Citation: AmphibiaWeb 2003 Hylorina sylvatica: Emerald Forest Frog <https://amphibiaweb.org/species/2639> University of California, Berkeley, CA, USA. Accessed May 29, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 29 May 2023.
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