This species is known from the crests and high Amazonian slopes of the Cordillera Oriental of the Andes in Cusco, Peru. Records from the Department of Cajamarca are most likely to be in error and have not been confirmed to belong to this species (A. Catenazzi pers. comm. April 2017). Presently, several subpopulations in the Cordillera Oriental in the Region of Cusco are assigned to this species: 3,080–3,580 m asl on the slopes of Abra Amparaes, 3,160–4,080 m asl on the slopes of Abra Málaga, and 3,100–3,200 m asl on the slopes of Abra Marcapata, though not all of these may represent G. excubitor. It has an altitudinal range of 3,080–4,080 m asl. It occurs in five threat-defined locations and its EOO is 6,151 km2.
Habitat and Ecology
It is a terrestrial species inhabiting humid puna with mosses and bunchgrass, above the treeline. It exhibits some resilience in the face of habitat disturbance, and may be found in low intensity farmed areas. Most individuals have been found beneath stones during the day or walking about in deep moss. Males have been heard calling at night from 20:30–22:30 (Duellman et al. 2011). Females have a single median brood pouch, which is used to brood the eggs until they hatch into froglets via direct development. On average, females have about 20 eggs (n=34) that measure about 6 mm in diameter (Duellman and Trueb 2015).
This species is common at Abra Acjanaco (Duellman et al. 2011). During a 1975 study, 12 individuals were collected at Abra Acanacu, 25 km NNE Paucartambo (Péfaur and Duellman 1980). Surveys in Cusco during 2007 and 2008 detected 20 individuals over 25 person-days and 15 individuals over 32 person-days, respectively (von May et al. 2008). In January 2009, several males were heard calling (exact number unknown) at Abra Acjanaco (Duellman et al. 2011). In the same year, 11 individuals were observed during surveys in montane forests along the Paucartambo–Shintuya road in Kosñipata Valley, Manu National Park (Catenazzi et al. 2011). Twelve frogs were collected along the Paucartambo-Shintuya road in the eastern slopes of the Cordillera de Paucartambo, Cusco during June–August 2012 (Burkart 2015). Surveys in 1996-1999, 2008–2009, and 2012–2016 recorded this species repeatedly within its known distribution, however slight declines in the subpopulations have been observed over this time and the species is not quite as abundant as it has been previously (A. Catenazzi pers. comm. 2017). Two dead individuals have also been recorded over this time period, although the cause for this is unknown (A. Catenazzi pers. comm. 2017, Burkart et al. 2017).
The major threat is extensive habitat loss due to agriculture (tea and coffee), burning of grasslands (A. Catenazzi pers. comm. April 2017) and the development of infrastructure for tourism (Aguilar et al. 2010).
The chytrid fungus Batrachochytrium dendrobatidis has been detected in this species at Kosñipata and other montane locations around Cusco (A. Catenazzi and V. Vredenburg pers. obs., Catenazzi et al. 2011, Kosch et al. 2012). In 2009, B. dendrobatidis prevalence was 18.2% (n=11) and mean infection intensity (Zswab) was 3,788.4 (Catenazzi et al. 2011). This species, however, appears to be resistant to the disease due to stronger anti-Bd skin bacteria (Burkart 2015, Catenazzi, Vredenburg et al. unpublished data).
This species is recorded from Manu National Park, Machu Picchu Historical Sanctuary, ACP Abra Málaga and ACP Ukumari Llakta, a private reserve established on 9 March 2007 covering a territory of 1,053 ha between Málaga Chico and Río San Luis.
Further habitat protection is required.
More information is needed on this species' distribution, population status, natural history, and threats. There is a need for close monitoring of the status of this species given the detection of chytridiomycosis.
Red List Status
Listed as Vulnerable because its extent of occurrence (EOO) is 6,151 km2, it occurs in five threat-defined locations, and there is continuing decline in the extent and quality of its forest habitat in the Peruvian Andes.
A distinct genetic difference exists between a specimen from Abra Amparaes and two individuals from Abra Acjanaco (Duellman et al. 2011). Much more extensive phylogenetic analyses most likely will reveal that G. excubitor, as it is now recognized, consists of two or more cryptic species (Duellman and Trueb 2015).
IUCN SSC Amphibian Specialist Group 2017. Gastrotheca excubitor. The IUCN Red List of Threatened Species 2017: e.T55333A136513666. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T55333A89203049.en .Downloaded on 21 January 2019