Tuesday 31 July 2012

Three new species of Frog from the Peruvian Andes.

Frogs of the genus Oreobates are found in the forests of Argentina, Brazil, Bolivia, Colombia, Ecuador, and Peru. They do not have a tadpole stage, developing into miniature frogs within their eggs. In a paper published in the American Museum Novitates on 20 July 2012, a team of scientists led by Jose Padial of the Division of Vertebrate Zoology (Herpetology) at the American Museum of Natural History, carry out a review of the genus Oreobates, taking into account recently collected specimens and genetic data which was not previously available, in which they describe three new members of the genus from the forests of the Peruvian Andes.

The first new species described is Oreobates amarakaeri, named in honour of the Amarakaeri Amazonian indigenous group who are intimately associated with the Amazonian forests. The frogs were discovered close to the rivers Mabe and Nusinuscato (both tributaries of the Río Araza) in the Río Madre de Dios basin in the Andean foothills. The area was forested, with dense clumps of thorny Bamboo. The frogs were active on the ground at night during the end of the rainy season, where they were collected by members of an exhibition led by Juan Chaparro of the Museo de Historia Natural at the Universidad Nacional de San Antonio Abad del Cusco; only male frogs were found.

Map showing the distribution of Oreobates amarakaeri (red stars), as well as that of a number of previously described species in the same genus. Padial et al. (2012). 

The location on the Río Nusinuscato in Cusco Province, Peru, at an altitude of about 685 m, where Oreobates amarakaeri was collected. Padial et al. (2012).

Oreobates amarakaeri is a small (slightly over 30 mm), warty, brown Frog with black, white, pink and gold markings. It is wartier on its dorsal surface (back), the warts on its flanks being roughly triangular in profile. It has long, slender, toes which lack webbing. The eyes are golden, with black pupils. 

Three male specimens of Oreobates amarakaeri. Padial et al. (2012).

The next species described is Oreobates gemcare, named for the GEMCare (Golden Empire Managed Care) medical group, which sponsored one of the exhibitions to Peru that contributed to this study. The population of Frogs assigned to Oreobates gemcare was previously assigned to another species, Oreobates lehri, when they were first described in 2007. However the genetic study which formed part of the research for this paper revealed that the two known populations of Oreobates lehri are in fact genetically distinct, so one of these populations, in the cloud forrests of the Andean hills of the Kosñipata Valley, is formally described as a separate species. Oreobates gemcare is a cryptic species, one that cannot be distinguished on morphological traits alone, but which has been shown to be distinct genetically.

The cloud forests of the Kosñipata Valley  in Cusco Province, Peru, at an altitude of about 2700 m, where Oreobates gemcare was collected. Padial et al. (2012).

Oreobates gemcare is a robust, warty, brown or grayish-brown Frog, 30-40 mm in length, with orange and yellow markings and a cream belly. The females are notably larger than the males. 

Oreobates gemcare. Four male specimens. Padial et al. (2012).

The third new species named is Oreobates machiguenga, named in honour of the Machiguenga Amazonian indigenous group, and in particular those of the Reserva Comunal Machiguenga, who both permitted and aided the collection of Frogs on their land. The Frogs were found on the slopes of Cordillera Vilcabamba, in the Río Kimbiri Valley, in the Río Apurimac Basin, in La Convención Province, Peru. The frog was found on montane forest floors in the rainy season.

Map of Peru showing the distribution of Oreobates gemcareOreobates machiguenga, and four other previously described members of the genus (including Oreobates lehri). Padial et al. (2012).

The montane forests of the Río Kimbiri, on the western slopes of Cordillera
Vilcabamba, Cusco, Peru, at about 1400 m, where Oreobates machiguenga was collected. Padial et al. (2012).

Oreobates machiguenga is a moderately robust Frog with granular skin on its back but otherwise smooth, described from a single, female, specimen. The Frog was brown, with darker markings; several large, orange, eggs could be seen through the skin.

Oreobates machiguenga. adial et al. (2012).

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