Rhinoderma rufum is a small frog, measuring 31 mm in SVL for males and 33 mm in SVL for females. A distinguishing feature is its fleshy proboscis. Tympana are indistinct. The forelimbs and hindlimbs are slender. Webbing is particularly extensive between the 1st and 2nd toes and between the 2nd and 3rd toes. This species can be highly variable in color. Dorsally, the color may be uniformly tan, brown, reddish brown, pale green, dark green, or a mixture of brown and green. The ventral surface has black and white splotches. Brooding males show enlarged vocal sacs (Crump 2003).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Chile
Rhinoderma rufum has a very restricted distribution in Central Chile, from Maule province south to BioBio province. This species has been found near slowly running streams in wet temperate beech forest at elevations from 50 to 500 meters
Life History, Abundance, Activity, and Special Behaviors
Both species in the genus Rhinoderma-- R. rufum and R. darwinii-- exhibit an unusual form of parental care: embryos are taken up into the male parent's vocal sacs. Rhinoderma rufum tadpoles are transported from the nest to water, where they are released from the male's vocal sacs, and metamorphose in the water. In contrast, R. darwinii has nonfeeding tadpoles which mature to froglets within the male vocal sacs, and receive nutrients from the male (Jorquera et al. 1982).
During the mating season, R. rufum males give off a mating call consisting of a rapid "pip, pip, pip, pip," with long pauses between repetitions (Crump 2003). Calls are made while the males are hidden in vegetation, on the surface of moist soil (Penna and Veloso 1990). The dominant frequency of the call is about 3000 Hz; this frequency is at the upper limit of the range for frogs found in the temperate austral forest (Penna and Veloso 1990). Rhinoderma rufum calls have been reported to show similarities to those of R. darwinii, a rare finding for frogs that are both related and sympatric
(Penna and Veloso 1990). It is not known how tadpole transport inside the vocal sacs might affect male calling characteristics (Penna and Veloso 1990).
The female lays a clutch of 12-24 eggs on moist ground (Crump 2003). The eggs are small, approximately 2.4 mm in diameter (Jorquera et al. 1974; Jorquera et al. 1982). Eight days later, when the larvae first start to move within the eggs, R. rufum males take up the eggs into their vocal sacs (Jorquera et al. 1982). The eggs hatch there and the tadpoles remain in the male frog's vocal sacs. When the tadpoles mature to the point of having developed keratinized jaws and a functioning digestive system (stage 3 of larval development), the male releases the tadpoles into the water (Jorquera et al. 1982). The tadpoles complete larval development (metamorphosis) in the water (Jorquera et al. 1982). Rhinoderma rufum larvae have external gills and a spiraculum tube, as well as an interdigital membrane and digital tubercules on the hindfeet
(Jorquera et al. 1974; Jorquera et al. 1982).
The Chile Darwin's frog is presumed to be a sit-and-wait predator which preys on small insects and other small invertebrates. This frog is terrestrial, and primarily diurnal (Crump 2003).
Trends and Threats
This species has not been seen for some years (IUCN, 2006). It may be extinct.
Possible reasons for amphibian decline
General habitat alteration and loss
Crump, M. L. (2003). ''Chile Darwin's frog, Rhinoderma rufum.'' Grzimek's Animal Life Encyclopedia, Volume 6, Amphibians. 2nd edition. Hutchins, M., Duellman, W. E., and Schlager, N., eds., Gale Group, Farmington Hills, Michigan.
IUCN, Conservation International, and Nature Serve. 2006. Global Amphibian Assessment. www.globalamphibians.org. Accessed on 28 June 2007.
Jorquera, B., Garrido, O., and Pugin, E. (1982). ''Comparative studies of the digestive tract development between Rhinoderma darwinii and Rhinoderma rufum.'' Journal of Herpetology, 16(3), 204-214.
Jorquera, B., Pugin, E., and Goicoechea, O. (1972). ''Tabla de desarrollo normal de Rhinoderma darwinii.'' Archivos de Medicina Veterinaria, 4, 1-15.
Penna, M. and Veloso, A. (1990). ''Vocal diversity in frogs of South American temperate forest.'' Journal of Herpetology, 24(1), 23-33.
Originally submitted by: Peera Chantasirivisal (first posted 2006-02-16)
Edited by: Kellie Whittaker, Michelle S. Koo (2023-01-08)
Species Account Citation: AmphibiaWeb 2023 Rhinoderma rufum: Chile Darwin's Frog <https://amphibiaweb.org/species/4323> University of California, Berkeley, CA, USA. Accessed Jun 4, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 4 Jun 2023.
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