This species is known only from the Uluguru, Udzungwa, Mahenge and Nguru Mountains in eastern and northeastern Tanzania, with an altitudinal range of approximately 350-1,950 m asl. It is unlikely that it may occur more widely (S. Loader pers. com. June 2012). Taking range as a proxy for extent of occurrence (EOO), this is estimated to be 3,113 km2. It is considered to occur in four threat-defined locations (S. Loader and J. Vonesh pers. comm. June 2012).
Habitat and Ecology
It is associated with rocky streams in montane forests, and is generally confined to mature forest (though is possibly more tolerant of open woodland situations than Petropedetes martiensseni). It lays its eggs on rocks over which water is trickling, close to torrential streams and waterfalls. The larvae remain attached to the rocks, where they develop. When not breeding, the adults can be found on the forest floor, in holes on the ground, and in rock crevices.
It is locally common in suitable habitat (S. Loader pers. comm. June 2012). Its population is considered to be severely fragmented (S. Loader pers. comm. June 2012).
It is likely to be adversely affected by general encroachment and degradation of the forest due to small-scale agriculture, and could also be affected by siltation of streams. It has been confirmed as carrying the fungus that causes chytridiomycosis (Udzungwa subpopulation), but it is not yet known if this will lead to a reduction in population numbers, as has been the case with amphibians in other parts of the world.
It occurs in the Udzungwa National Park, the proposed Udzugwa scarp, Mkingu and the Uluguru Nature Reserves (S. Loader and J. Vonesh pers. comm. June 2012), although there is a need for expanded and strengthened protection of forests. More information is needed on its ecology and threats, especially the potential impact of the chytrid fungus, which has been confirmed in this species. Subpopulations should therefore be carefully monitored. Clarification of its taxonomic identity is also needed.
Red List Status
Listed as Endangered because its extent of occurrence (EOO) is estimated to be 3,113 km2, it is known from four threat-defined locations, its distribution is considered to be severely fragmented, and the extent of its forest habitat on the Uluguru, Udzungwa and Mahenge Mountains is declining.
Molecular data suggest that there are more than one species under this name (S. Loader pers. comm. June 2012).
IUCN SSC Amphibian Specialist Group 2013. Arthroleptides yakusini. The IUCN Red List of Threatened Species 2013: e.T58065A17195247. http://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T58065A17195247.en .Downloaded on 14 December 2018