This species is known only from the West Usambara Mountains in Tanzania (Loader et al. 2011). Previous records of this species from the East Usambara Mountains, the Nguru Mountains, and the Ukaguru Mountains are now known to refer to other species (S. Stuart pers. com. October 2013). It is a montane species, with an altitudinal range from 1,400 to 2,000 m asl. Its extent of occurrence (EOO) is estimated to be 940 km². It is considered to occur in one threat-defined location given that known forest patches in this area are considered to be more or less equally threatened (S. Loader pers. comm. June 2012, October 2013).
Habitat and Ecology
This species occurs in the leaf-litter of montane forests. It has not been found outside good forest and therefore might not be able to cope with substantial habitat loss or disturbance (S. Loader pers. comm July 2013). Presumably it breeds by direct development, like other members of the genus.
There is no specific information on the species' population. However, population decline is assumed due to ongoing loss of habitat.
There is continuing loss of its forest habitat due to the expansion of agriculture, wood extraction, and human settlements.
The species occurs in the Mazumbai, Baga II, Shume-Magamba Forest Reserves in the West Usambara Mountains. All of these forest reserves require further protection. More information is needed on its population and ecology, and the effects on the degree of habitat disturbance tolerated by this species need to be investigated.
Red List Status
Listed as Endangered because its extent of occurrence (EOO) is estimated to be 940 km², it is considered to occur in one threat-defined location, and there is a continuing decline in the extent and quality of its forest habitat in the West Usambara Mountains.
A recent study has confined this species to forests of the West Usambara Mountains (Loader et al. 2011).
IUCN SSC Amphibian Specialist Group 2015. Arthroleptis tanneri. The IUCN Red List of Threatened Species 2015: e.T54388A16934674. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T54388A16934674.en .Downloaded on 16 January 2019