This species is known only from the type locality in the northern Cordillera Central, municipality of Anorí, Antioquia Department, Colombia, between 1,670–1,875 m asl (Bravo-Valencia and Rivera-Correa 2011). Its area of occupancy (AOO) is estimated as 4 km2 (using a grid cell of 2x2 km) and its extent of occurrence (EOO) is 10 km2.
Habitat and Ecology
This nocturnal species is found in remnant secondary very humid pre-montane forest. The habitat is characterized by a high abundance of arboreal ferns, bromeliads and other epiphytes. The species is most active at night and all but one specimen were captured a night. Individuals have been found during the dry season (February) near a stream on leaves of vegetation up to 1 m above the ground. Although the breeding biology of this species is not known, it is presumed to undergo larval development within streams.
The population status of this species is unknown. It is a recently described species which has only been recorded a couple times, from its discovery in 2003 and again in 2007 (Bravo-Valencia and Rivera-Correa 2011). Only a dozen individuals have been found in spite of exhaustive searches conducted over ten years at the type locality and nearby areas with suitable habitat (M. Rivera-Correa pers. comm. 2016).
The species is only known from within a protected area and anthropogenic activities, such as habitat loss, do not currently pose a threat. A likely threat to this species is chytridiomycosis, a factor implicated in catastrophic population declines in many montane species of Atelopus (Bravo-Valencia and Rivera-Correa 2011), however there is no further information on this threat.
The only known specimens of this species were collected within two contiguous protected areas, Reserva Natural de las Aves Arrierito Antioqueño and Reserva La Forzosa.
Given the threat of chytridiomycosis, a captive-breeding programme might need to be established for this species.
More information is needed on this species' distribution, population status, ecology, and threats. Further survey work is needed to determine if it occurs outside the vicinity of the type locality. Studies are needed to obtain information on its susceptibility to threatening processes, including chytrid fungus.
Red List Status
Critically Endangered (CR)
Atelopus nocturnus is listed as Critically Endangered because the total population size is believed to be less than 50 mature individuals and, along with the potential threat of chytridiomycosis, this small population size itself is of concern. In addition, this species has only been found at one location within a small protected reserve and it may be prone to the effects of stochastic events within a very short time period in an uncertain future.
IUCN SSC Amphibian Specialist Group 2017. Atelopus nocturnus. The IUCN Red List of Threatened Species 2017: e.T21567292A21567295. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T21567292A21567295.en .Downloaded on 22 January 2019