Comprehensive DescriptionRead full entry
A large (Males 28-34 mm, females 32-35 mm) forest Afrixalus from West Africa. Dorsum dark brown with a light pattern normally leaving a brown lumbar band and a rectangular brown dorsal spot, the anterior part of which normally extends a little up onto the upper eyelid. Tibia with two light spots.
Although the pattern can vary, A. nigeriensis is easy to distinguish from the only other brown and silverish Afrixalus occurring together with it, namely A. dorsalis. A. nigeriensis is larger, with broader head, more protruding eyes and with discs and fingers bright orange in life.
Some of the known samples of this species, namely those from Côte dIvoire and Ghana, show considerable variation in pattern. The silverish pattern that seems to overlay the dark brown ground colour can vary both in extent, being more or less reduced, and in "density" in the way that the dark ground colour sometimes peeps through the silverish cover as diffuse spots. Since this great variation in pattern has been found in samples from single localities, it apparently does not have systematic significance.
When described in 1963 this frog seemed to belong with a group of forms regarded as subspecies of the central African A. congicus (now termed A. osorioi), as did the Cameronese A. paradorsalis, but for morphological and zoogeographical reasons it is best regarded as a full species.
The voice is typical of the larger Afrixalus: a slow, creaking initial sound is followed by a succession of rather unmeloduous clicks with an indistinct frequency-intensity maximum of about 3000-3300 cps. and a rate of about 8-9 per second.
This account was taken from "Treefrogs of Africa" by Arne Schiøtz with kind permission from Edition Chimaira publishers, Frankfurt am Main.