This species is only known from its type locality of Mesopotamia, near Páramo de Sonsón, in the municipality of Sonsón, Vereda Caunzal, on the eastern side of the Cordillera Central, about 15 km to the east of the municipality of Argelia, Colombia. It was recorded at 1,500 m asl, and might occur more widely. Its extent of occurrence (EOO) is 359 km2.
Habitat and Ecology
This species occurs on the ground in the understorey of forest along streams; it has not been recorded from disturbed habitats. Breeding and larval development take place in streams.
There are no recent records for this species, despite surveys at the type locality and nearby areas. It had not been recorded since its discovery in 1996. There are only 13 specimens in museum collections. In 2008, Fundación ProAves reported a rediscovery of this species, but it was a misidentification (Colombia Red List Assessment Workshop August 2016). In 2010, there were surveys to find this species but they were not successful (Colombia Red List Assessment Workshop August 2016).
The main threat to this species is habitat loss and degradation due to agricultural activities (including pollution from agrochemicals). The 2004 assessment reported that chytridiomycosis was probably the major threat, leading to a catastrophic population decline. While there is currently no direct information confirming that chytrid has caused declines in this species, the lack of records since the 1990s is consistent with the pattern of decline in many other montane Atelopus species, and it is therefore reasonable to infer that the disease might have been the cause of declines in this species (Colombia Red List Assessment Workshop August 2016).
This species has not been recorded in any protected areas.
In view of the threat of chytridiomycosis, ex situ populations might need to be established should any further individuals be located in the wild.
Research is needed to better determine its distribution, population size and trends and the threats that may be affecting it.
Red List Status
Critically Endangered (CR)
This species is known only from the type locality in the Cordillera Central of Colombia and has not been recorded since its discovery in 1996. Recent efforts directed to find the species at the type locality and nearby areas have not been successful. It is suspected that the number of mature individuals would be fewer than 50. It is therefore listed as Critically Endangered (Possibly Extinct).
IUCN SSC Amphibian Specialist Group 2017. Atelopus sonsonensis. The IUCN Red List of Threatened Species 2017: e.T54553A49537963. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T54553A49537963.en .Downloaded on 15 November 2018