Eupsophus altor
Oncol's ground frog, Rana de hojarasca
family: Alsodidae
Species Description: Nunez JJ, Rabanal FE, Formas JR 2012 Description of a new species of Eupsophus (Amphibia: Neobatrachia) from the Valdivian coastal range, southern Chile: an integrative taxonomic approach. Zootaxa 3305: 53-68.

© 2013 Bert Willaert (1 of 2)
Conservation Status (definitions)
IUCN (Red List) Status
Other International Status None
National Status None
Regional Status None


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Eupsophus altor is a frog with a snout-vent length that ranges from 33.5 to 42.0mm for both sexes. The head is broad and is 0.93 times narrower than the body. The snout is rounded, with slightly prominent nostrils. Tympanum is round and visible. Eyes are oriented laterally and prominent. Pupil shape is not described in adult frogs. Skin is smooth on the surfaces of the head, dorsal, ventral, and limb. Dorsolateral folds are well developed. The forelimbs are slender and the hindlimbs are long and slender. Fingertips are rounded and relative lengths are III > IV > II > I with fingers I and II bearing nuptial pads. Toes are thin, long, have rounded tips and have relative length of IV > V = III > II > I with a small amount of webbing between toes III and IV. Metatarsal tubercle is developed and egg-shaped. Tadpoles are type IV (spiracle oriented sinestrally) with lengths between 18.4-19.6mm. Tadpole body shapes are elliptical and depressed slightly. Low tail fins are 0.70 times the length of the tadpole. Tail tip is rounded. Nostrils located closer to anterior end of snout rather than eye. Vent is located medially. Oral disc is emarginated slightly with one row of marginal papillae. Both upper and lower jaws are heavily keratinized. Rostral gap is present while mental gap is absent (Nuñez et al. 2012).

Eupsophus altor can be distinguished from other species by the following prominent cranial characteristics: deep palatal shelf of premaxilla, large pterygoid process, small nasals, nasals contacting maxillae, a type II cervical cotylar arrangement, moderately long zygomatic ramus of squamosal, long otic ramus of squamosal, broad and separate odontoid-ridge-bearing palatines, spheno-ethmoid whole and extends to contact with anterior edge of nasals. Endotrophic tadpoles. Differentiated from other Eupsophus species by its wintertime breeding, terrestrial tadpoles and unique advertisement call (Nuñez et al. 2012).

In both life and in preservative, dorsal coloration ranges from reddish to pink. Flank coloration is white with yellow in the axillary and inguinal areas. Ventral coloration is white. Light-gray spots are present on the dorsal surface, light-gray bracelets are present on the extremities, small melanophores distributed on ventral surface and the iris is yellow with black networking. In preservative, color is similar to color in life. (Nuñez et al. 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Chile


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The range of Eupsophus altor is restricted to the western slopes of the coastal range of the Valdivia Province in Southern Chile. Habitat is typical of the Valdivian rain forest (Nuñez et al. 2012). Elevation range is not given, however elevation in the coastal range of the Valdivia Province does not exceed 715 m.

Life History, Abundance, Activity, and Special Behaviors
Eupsophus altor can be found underneath rotted trees, and walking on the ground through vegetation at night. Tadpoles were always found away from a body of water. A male was always seen close to a group of tadpoles. Breeding season is during the early winter. Male calls consist of one note, with an average duration of 336ms. The range of the dominant frequency is between 1317-2098 Hz. Calls are high in harmonics. Amplexus was not observed. Tadpoles were observed in covered, moist burrows. Development, diet and predatory behaviors were not observed (Nuñez et al. 2012).

The karyotype of Eupsophus altor is 2n=30 (Nuñez et al. 2012).

The species authority is Nuñez, Rabanal, and Formas (2012).

This species was once thought to be Euposophus roseus, however, recent molecular analyses shows that Eupsophus altor is a separate and distinct lineage from E. roseus (Nuñez et al. 2012). The name, altor, is derived from Latin, meaning “one who looks after or brings up its offspring.” It is given because males were observed near clutches of tadpoles (Nuñez et al. 2012).


Nuñez, José J., Felipe E. Rabanal, and J. Ramon Formas. ''Description of a New Species of Eupsophus (Amphibia: Neobatrachia) from the Valdivian Coastal Range, Southern Chile: An Integrative Taxonomic Approach.'' Zootaxa 3305 (2012): 53-68

Written by Anthony Gilbert (Anthony.Gilbert09 AT, University of California Berkeley
First submitted 2013-06-14
Edited by Ann T. Chang (2013-07-14)

Species Account Citation: AmphibiaWeb 2013 Eupsophus altor: Oncol's ground frog <> University of California, Berkeley, CA, USA. Accessed Aug 19, 2017.

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Citation: AmphibiaWeb. 2017. <> University of California, Berkeley, CA, USA. Accessed 19 Aug 2017.

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