This species is only known from the type locality in Marojejy National Park at 1,326 m asl in the north east of Madagascar (Glaw and Vences, 2011). Its elevational range is unknown - it may occur both higher and lower than currently recorded - and the limits of its range are also unknown, so it has tentatively been mapped to the boundaries of the Park and its extent of occurrence (EOO) is 780 km2.
Habitat and Ecology
The holotype was collected in the forest in early evening, calling from the vegetation about 1m above the ground, at about 2-3m distance from a small stream in a mountainous rainforest, close to a cleared campsite (Glaw and Vences, 2011).
It is only known from two specimens - this species is either very seasonal and cryptic, or it is rare and restricted to special habitats (Glaw and Vences, 2011). Attempts to find more specimens at the type locality by searching for calling and non-calling specimens along the stream where the holotype was discovered, and in adjacent rainforest areas, were unsuccessful and extensive surveys by other teams in Marojejy (Raselimanana et al., 2000) apparently failed to record this distinctively coloured species as well (Glaw and Vences, 2011). The trend of the population is unknown, but it could be decreasing if it occurs within the mapped area and where habitat loss is occurring.
Intensive illegal wood extraction of rosewood species within Marojejy National Park that followed the 2009 political crisis of Madagascar caused concerns for the survival of rainforest–restricted species, such as this one. However, while illegal rosewood logging has probably ceased, wood extraction currently taking place in the Park seems to occur at lower elevations and is not thought to have reached elevations where this species has been recorded; along the boundaries of Marojejy deforestation is taking place to clear land for agriculture (F. Glaw pers. comm. November 2015).
Species in this genus have tested positive for Batrachochytrium dendrobatidis (Bd), however currently there have been no negative effects observed within amphibian populations in Madagascar suggesting the Bd strain has a low virulence level (Bletz et al., 2015).
This species occurs in Marojejy National Park.
Improved protection of forests in the region is required.
Further research is required to clarify the species' distribution, population size and trend, and it is essential to fully understand the distribution, origin, type and virulence of Bd lineages found in Madagascar (Bletz et al., 2015).
Red List Status
Listed as Endangered because the extent of occurrence is 780 km2, it is known from fewer than five threat-defined locations and there is continuing decline in the extent and quality of its habitat in northeastern Madagascar.
This species has been addressed before as Gephyromantis spec. aff. horridus "Marojejy" by Glaw and Vences (2007) and as confirmed candidate species Gephyromantis spec. 11 by Vieites et al. (2009).
IUCN SSC Amphibian Specialist Group 2016. Gephyromantis ranjomavo. The IUCN Red List of Threatened Species 2016: e.T49564032A49564337. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T49564032A49564337.en