Didynamipus sjostedti, The Four Digit Toad

Didynamipus sjostedti is presently classified as ‘endangered’ (EN) by the International Union for Conservation of Nature (IUCN). Presently this species appears on no other lists (e.g. CITES) requiring monitoring or affording any measure of protection. The classification of D. sjostedti as endangered is based on it satisfying criteria meriting such consideration during its last assessment by the IUCN in 2004.

Didynamipus sjostedti was once considered the rarest bufonid in Africa (Grandison 1981), being known from only two locations (Bioko and SW Cameroon) and 6 specimens. Since that time, no fewer than five additional populations have been discovered, extending the range into southeastern Nigeria and northwestern Cameroon.

 

Occurring in primary and secondary forests, edges and even clearings at elevations of 200-1250m, D. sjostedti inhabits a remarkably broad range of habitats. The occurrence of this species within a given area appears to be highly localized, occurring in ‘congregations’ of five to 40 individuals (Gartshore 1984).

Didynamipus sjostedti was described in 1903 from “Kamerun” (Cameroon) and in 1906 (as Atelophryne minuta, synonym) from the island of Bioko, Equatorial Guinea. In the most recent assessment of this species by the IUCN in 2004 it was stated that there is no recent information of its status on Bioko as it had not been seen since 1965. Weinberg (2008) has since published the results of a photographic survey of the amphibians of Bioko that reported the observation of D. sjostedti “in abundance” on the southern slope of Pico Basile.
In addition to Bioko, the IUCN report describes five (5) known populations, for a total of six (Mt. Cameroon, Kedonge Forest Reserve, Mokoko Forest Reserve, Baro [outside Korup NP] and Oban Hills, Nigeria).