Description
Hemiphractus proboscideus adult females range from 57-66 mm long while the males are 43-50 mm. This species can be identified by a distinctive large triangular head, with a fleshy, sharply pointed snout and protruding tubercles on the upper eyelids (Duellman 2003). Frogs of the genus Hemiphractus are casque-headed, with large, angular ornamented skull bones; the skin is co-ossified to the cranial elements (Sheil et al. 2001). This species also has odontoids, fang-like outgrowths of the lower jaw which are superficially similar to teeth but not equivalent to true teeth (Trueb 1973; Shaw 1989a; Shaw 1989b). This frog has a flattened or depressed body. Vertebral neural spines form skin-covered projections on the back. Forearm tubercles are present and arrayed in neat horizontal rows. Heel spurs (calcars) are present. Dorsally, this species is brown or tan in color. The dorsal and lateral surfaces of the body and upper surfaces of the limbs have irregular green, brown, or gray stripes and spots. Ventrally, the coloration is brown with lighter tan or orange dots. The tongue and interior of the mouth are a striking yellow color (Duellman 2003; Bartlett and Bartlett 2003).

Embryos in the subfamily Hemiphractinae (marsupial frogs) are characterized by unique, membranous bell-shaped gills (Noble 1927; del Pino and Escobar 1981). These gills are derived from the branchial arches (Noble 1927; del Pino and Escobar 1981) and allow respiration during development in the egg (Mendelson et al., 2000). Hemiphractus proboscideus is a direct developer, and does not have a free-living larval stage (Trueb 1974; del Pino and Escobar 1981).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Colombia, Ecuador, Peru

View distribution map in BerkeleyMapper.

This species is found in the Upper Amazon Basin as well as the lower slopes of the Andes, within southern Colombia, Ecuador, and Peru. It inhabits humid lowland to lower montane forest at elevations up to 1200 m above sea level (Duellman 2003; Stuart et al. 2008). It has been found in both primary and secondary forest (Duellman 1978).

Life History, Abundance, Activity, and Special Behaviors
Hemiphractus proboscideus is nocturnal. It makes use of arboreal habitat, preferring vegetation 1 to 2.5 m above the forest floor. This species is active on both rainy and dry nights (Duellman 2003).

Frogs in the subfamily Hemiphractinae, including those in the genus Hemiphractus, are known as marsupial frogs. Hemiphractus proboscideus is considered one of the basal members of this genus since the female incubates the eggs on her back but lacks a brooding pouch for doing so. During the mating season, the female carries up to 26 large eggs exposed on her back, adhered by gelatinous substances. This species has direct development where small froglets hatch directly out of the eggs, without going through a free-living larval stage (Trueb 1974; del Pino and Escobar 1981).

The adult diet consists of other frogs as well as small lizards and large arthropods (Duellman 2003), constituting relatively large and resistant prey (Fabrezi and Emerson 2003). Hemiphractus proboscideus has large "fangs" on the bottom jaw, which have most likely evolved in the context of dietary specialization rather than sexual selection, since fang size is not sexually dimorphic in this species (Fabrezi and Emerson 2003).

When defending itself, Hemiphractus proboscideus will open the mouth to show a bright yellow tongue (Duellman 2003).

Trends and Threats
Hemiphractus proboscideus is not threatened. There may be population declines within Ecuador (Stuart et al. 2008).

Possible reasons for amphibian decline

General habitat alteration and loss

References

Bartlett, R. D. and Bartlett, P. (2003). Reptiles and Amphibians of the Amazon. University Press of Florida, Gainesville.

Duellman, W. E. (1978). ''The biology of an equatorial herpetofauna in Amazonian Ecuador.'' Miscellaneous Publications of the University of Kansas Museum of Natural History, 65, 1-352.

Duellman, W. E. (2003). ''Sumaco horned treefrog, Hemiphractus proboscideus.'' Grzimek's Animal Life Encyclopedia, Volume 6, Amphibians. 2nd edition. M. Hutchins, W. E. Duellman, and N. Schlager, eds., Gale Group, Farmington Hills, Michigan.

Fabrezi, M. and Emerson, S. B. (2003). ''Parallelism and convergence in anuran fangs.'' Journal of Zoology (London), 260, 41-51.

Mendelson, J. R. III, Da Silva, H. R., and Maglia, A. M. (2000). ''Phylogenetic relationships among marsupial frog genera (Anura: Hylidae: Hemiphractinae) based on evidence from morphology and natural history.'' Zoological Journal of the Linnaean Society, 128, 125-148.

Noble, G. K. (1927). ''The value of life history data in the study of the evolution of the Amphibia.'' Annals of the New York Academy of Sciences, 30, 31-128.

Shaw, J. P. and Ellis, S. A. (1989). ''A scanning electron microscope study of the odontoids and teeth in Hemiphractus proboscideus (Anura:Hylidae).'' Journal of Zoology (London), 219, 533-544.

Sheil, C. A., Mendelson, J. R., III, and Da Silva, H. R. (2001). ''Phylogenetic relationships of the species of neotropical horned frogs, genus Hemiphractus (Anura: Hylidae: Hemiphractinae), based on evidence from morphology.'' Herpetologica, 57, 203-214.

Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.

Trueb, L. (1973). ''Bones, frogs and evolution.'' Evolutionary Biology of the Anurans: Contemporary Research on Major Problems. J. L. Vial, eds., University of Missouri Press, Columbia, Missouri, 65-132.

Trueb, L. (1974). ''Systematic relationships of neotropical horned frogs, genus Hemiphractus (Anura, Hylidae).'' Occasional Papers of the Museum of Natural History of the University of Kansas, 29, 1-60.

del Pino, E. M. and Escobar, B. (1981). ''Embryonic stages of Gastrotheca riobambae (Fowler) during maternal incubation and comparison with development of other marsupial frogs.'' Journal of Morphology, 167, 277-295.

Species Account Citation: AmphibiaWeb 2009 Hemiphractus proboscideus: Sumaco Horned Treefrog <https://amphibiaweb.org/species/1411> University of California, Berkeley, CA, USA. Accessed Dec 26, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 26 Dec 2024.

AmphibiaWeb's policy on data use.