Rhinodermatidae

(Rhinodermatidae)

Class: Amphibia

Order: Anura

Family: Rhinodermatidae

Thumbnail description
Small frogs; green, tan, or brown (or a combination of these colors) with a distinctive fleshy proboscis at the tip of the snout

Size
Snout-vent length to 1.3 in (33.0 mm)

Number of genera, species
1 genus; 2 species

Habitat
Forest and open areas; often near streams

Conservation status
Data Deficient: 2 species

Distribution
Chile, Argentina

Evolution and systematics

No fossils have been described for the family.

Frogs belonging to the family Rhinodermatidae have been included in the families Brachycephalidae, Dendrobatidae, and Leptodactylidae at various times. Since 1971 they have been recognized in their own family.

Rhinoderma rufum was originally named Heminectes rufus. These frogs were later considered to be a local variant of Rhinoderma darwinii, rather than a valid species. Subsequent work suggested that Heminectes is a synonym of Rhinoderma. The new combination of Rhinoderma rufum was proposed based on differences in the mating call, karyotype, larval development, and male parental care between the two species. No subfamilies are recognized.

Physical characteristics

Rhinodermatids are small frogs; males range from 0.9–1.2 in (22–31 mm), females from 1–1.3 in (25–33 mm). The tympana (external eardrums) are indistinct. The most distinctive external characteristic is a fleshy proboscis, found in both sexes and all age classes. The forelimbs and hind limbs are rather long and slender. These frogs are extremely variable in color. Dorsally, they may be uniformly tan, brown, or reddish brown; uniformly pale green or dark green; or a combination of brown and green, in variable patterns. The underside has blotches of black and white. Brooding males are easily distinguished by their enlarged vocal sacs.

Distribution

Vocal sac-brooding frogs are found in central to southern Chile, and in Argentina near the Chilean border. Many populations have declined or disappeared from their historical sites during the past 15 years.

Habitat

These terrestrial frogs are found in wet temperate southern beech forest (Nothofagus), often near slowly running streams or in swampy areas, and in open areas around human habitation.

Behavior

Both species exhibit seasonal patterns of activity. They take refuge during the colder months, presumably under moss or logs on the ground, and breed during the warmer months. Both species are primarily diurnal. Territoriality has not been reported.

Feeding ecology and diet

The feeding ecology and diet of these frogs have not been studied. Anecdotal field observations suggest they opportunistically eat insects and other small invertebrates. In captivity they eat fruit flies, aphids, and juvenile crickets. Both species are sit-and-wait predators, that is, they sit in one place and snap up prey that come within striking distance.

Reproductive biology

Breeding is seasonal. Males call from land to attract females. Eggs are fertilized on moist ground, and males attend the eggs. Just before the eggs hatch, the males take the eggs into their mouths, where they slide into the vocal sacs. In Rhinoderma darwinii, the tadpoles develop within the vocal sac until they metamorphose 50–70 days later. In Rhinoderma rufum, the male releases the tadpoles into water, where they continue to develop for an unknown period of time.

Conservation status

Both species are listed as Data Deficient by the IUCN. However, Rhinoderma rufum is listed as Endangered and R. darwinii as Vulnerable by CITES. Possible reasons for population declines and disappearances include habitat destruction and modification, climate change, and detrimental effects from increased levels of ultraviolet radiation. No specific efforts are known to be underway to protect these species.

Significance to humans

None known.

Species accounts

Resources

Busse, Klaus. "Bemerkungen zum Fortpflanzungsverhalten und zur Zucht von Rhinoderma darwinii." Herpetofauna 13 (1991): 11–21.

Crump, Martha L. "Natural History of Darwin's Frog, Rhinoderma darwinii." Herpetological Natural History 9, no. 1 (2002): 21–30.

Formas, Ramón, Emilio Pugin, and Boris Jorquera. "La identidad del batracio Chileno Heminectes rufus Philippi, 1902." Physis Sección C. Buenos Aires 34 (1975): 147–157.

Goicoechea, Oscar, Orlando Garrido, and Boris Jorquera. "Evidence for a Trophic Paternal-Larval Relationship in the Frog Rhinoderma darwinii." Journal of Herpetology 20 (1986): 168–178.

Jorquera, Boris. "Biologia de la reproducción del genero Rhinoderma." Anales del Museo de Historia Natural Valparaíso 17 (1986): 53–62.

Jorquera, Boris, Emilio Pugin, and Oscar Goicoechea. "Tabla de desarrollo normal de Rhinoderma darwini." Archivos de Medicina Veterinaria 4 (1972): 1–15.

Jorquera, Boris, Emilio Pugin, Orlando Garrido, Oscar Goicoechea, and Ramón Formas. "Procedimiento de desarrollo en dos especies del genero Rhinoderma." Medio Ambiente 5 (1981): 58–71.

[Article by: Martha Lynn Crump, PhD]

Common name: Darwin's frogs

Darwin's Frogs
Darwin's Frog (Rhinoderma darwinii)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Amphibia Order: Anura Family: Rhinodermatidae Genus: Rhinoderma Duméril & Bibron, 1841
Distribution of Rhinodermatidae (in black)
Species
R. darwinii R. rufum

Rhinodermatidae are a family of small frogs found on the south-west coast of South America^[1]. There is only one genus (Rhinoderma), with just two species, of which the Chile Darwin's Frog (R. rufum) is highly endangered or may already be extinct. The better known Darwin's Frog (R. darwinii) is vulnerable.

Both species are notable for their unusual breeding, with the tadpoles being raised inside the mouth of the male^[1]. The eggs are laid on the ground. The male frog will transport the tadpoles into its enlarged vocal sac. In the Chile Darwin's Frog, the tadpoles are transported to a water source and released for the duration of their development. In Darwin's Frog, they will reside in the vocal sac until metamorphosis. They may carry between 5 and 15 offspring. Darwin's frogs are separated into a separate family based purely upon this behavioural adaptation, which is unique among frogs.

Darwin's frogs are small, reaching a size of only 3 centimetres (1.2 in) in length^[1]. They are predominantly green frogs, with patches of brown, and have a long, narrow nose. They are primarily terrestrial.

References

1. ^ ^{a b c} Zweifel, Robert G. (1998). Cogger, H.G. & Zweifel, R.G.. ed. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. p. 103. ISBN 0-12-178560-2. 

• Cogger, H.G.; R.G. Zweifel, and D. Kirschner (2004). Encyclopedia of Reptiles & Amphibians Second Edition. Fog City Press. ISBN 1-877019-69-0. 
• "ADW: Rhinodermatidae: Information". http://animaldiversity.ummz.umich.edu/site/accounts/information/Rhinodermatidae.html. Retrieved on 2006-05-08. 

v • d • e Extant anuran families by suborder Kingdom Animalia · Phylum Chordata · Subphylum Craniata · Superclass Tetrapoda · Class Amphibia Archaeobatrachia Ascaphidae · Bombinatoridae · Discoglossidae · Leiopelmatidae Mesobatrachia Megophryidae · Pelobatidae · Pelodytidae · Pipidae · Scaphiopodidae · Rhinophrynidae Neobatrachia Amphignathodontidae · Aromobatidae · Arthroleptidae · Brachycephalidae · Bufonidae · Centrolenidae · Dendrobatidae · Heleophrynidae · Hemisotidae · Hylidae · Hyperoliidae · Leptodactylidae · Mantellidae · Microhylidae · Myobatrachidae · Petropedetidae · Ranidae · Rhacophoridae · Rhinodermatidae · Sooglossidae

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