This species is only known from its type locality on the Befosa River, Antetikalambazaha, Tsaratanana Massif, in northern Madagascar between 1,580-1,650 m asl (Cramer et al. 2008). The species was not found at any of the surrounding surveyed sites (as listed by Rabibisoa et al. in press) in the Tsaratanana Massif, which is a well-known area of herpetological endemism (Cramer et al. 2008), suggesting it may be endemic to the Massif. This distinctive and relatively large species has also not been found in other forested areas of this elevation in northern Madagascar, therefore it is reasonable to conclude that it is endemic to the region (C. Raxworthy pers. comm. August 2016). Its EOO is 10 km².
Habitat and Ecology
The species appears to be restricted to humid rainforest habitat in close proximity to streams, and individuals may be found either on the ground, leaves, branches, or vertical tree trunks (Cramer et al. 2008). It is suspected to lay its eggs on leaves or possibly rock surfaces overhanging water; tadpoles are free swimming, developing in streams (Cramer et al. 2008).
Surveys have failed to detect this species outside of its type locality in Tsaratanana Massif (Rabibisoa et al. in press) and in other forested parts of northern Madagascar (C. Raxworthy pers. comm. August 2016). Due to ongoing decline in the extent and quality of its habitat, the population is suspected to be decreasing.
Forest in this area may be becoming degraded due to edge effects from fire or cattle grazing (C. Raxworthy pers. comm. August 2016).
The species is only known from a single forested site that is currently outside the protected area of the Tsaratanana Strict Nature Reserve (Cramer et al. 2008). The type locality, however, is on the main trail leading from Mangindrano village to the Maromokotro summit and plans are being developed to include this forest within a new protected area or extension of the original Tsaratanana Strict Nature Reserve, and the discovery of this species has reinforced the importance of protecting the area (Cramer et al. 2008).
As of 2016, this site is not yet protected (C. Raxworthy pers. comm. August 2016), but expanding this protection would ensure the survival of the species.
Further work is required to better understand the population size, distribution and trends. The known locality is close to the forest limit, and research is also needed to assess if forest in this region is becoming degraded (C. Raxworthy pers. comm. August 2016).
Red List Status
Critically Endangered (CR)
Listed as Critically Endangered because its extent of occurrence (EOO) is 10 km2, it occurs in one threat-defined location, and there is continuing decline in the extent and quality of its habitat.
IUCN SSC Amphibian Specialist Group 2017. Spinomantis nussbaumi. The IUCN Red List of Threatened Species 2017: e.T49581681A49581754. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T49581681A49581754.en