Atelopus petersi occurs in the Cordillera Oriental of the Andes in Ecuador, Provinces of Napo and Chimborazo, at elevations of 2,660-3,300 m asl (Coloma et al. 2007).
Habitat and Ecology
The species inhabits montane cloud forest and high montane evergreen forest. Knowledge on the life history of Atelopus petersi is poor. Individuals were formerly found under rocks at the edge of a stream, in streambeds, under logs on grassy hillsides, on cushion plants in paramo habitat, on a trail, along the border of the river. Atelopus petersi (as A. pachydermus) occurs sympatrically with A. ignescens sensu stricto (Coloma et al. 2007).
The last record for this species in Napo Province was a dead individual, found on 8 November 1996. Despite occasional efforts to locate A. petersi subsequently, no additional individuals have been found. In the past, A. petersi was a very common species in the vicinity of Papallacta. Interviews with local people revealed that these toads once were abundant but have not been seen for several years, although in Oyacachi some people claimed, on September 2003, that from time to time they still see single individuals (Coloma et al. 2007).
The area of occurrence of Atelopus petersi is close is to areas where climate abnormalities have occurred and Atelopus and Telmatobius extinctions have been reported. They are also close to areas where the chytrid fungus has occurred, or its presence is predicted. Given this scenario and considering the overwhelming evidence that Atelopus has been affected by these two key factors in the highlands, it is likely that A. petersi may be extinct, although the possibility of existing relictual populations may not be overlooked (Coloma et al. 2007).
Its altitudinal range overlaps with that of Reserva Ecológica Cayambe-Coca (Coloma 2005).
Atelopus petersi can be distinguished from other similar species by a combination of morphological features and different colour patterns (Coloma et al. 2007).
Luis A. Coloma 2008. Atelopus petersi. In: IUCN 2014