A medium-sized clawed frog with button-like protruding eyes situated dorsally. Body flattened. Adults measure 38-60mm (SVL). The subocular tentacles are well developed, reaching about 0.6-1 of the eye diameter. The skin is almost smooth. Starting at the posterior border of the eye, a double line of elongate unpigmented flat sensory tubercles (lateral line sense organs) is arranged in roughly alternating order. The outer line comprises 20-29 tubercles set at right angles to the body axis. The inner one runs parallel to the latter, comprising about 16-20 tubercles. Furthermore, 3-7 pairs of these tubercles appear in the neck region, and 10-14 ones are found on the border of the lower jaw, set at right angles to the mouth. Like all of the dorsal surface, this part of the skin is scattered with numerous minute asperities which are equally unpigmented. Some of these may also be found on the fingers which are covered with numerous minute grooves. On breeding males, the outer part of the fingers is black. The dermal lobes above the vent are better developed in females. The web of the hind limbs is fully developed. Toes 3-5 have black horny claws. Metatarsal tubercle without claw. 2n = 36.
According to Stewart (1967), males from Malawi reach a SVL of 58 mm, females 72 mm. Concurring measurements were published by Nieden (1923), Poynton (1964a), Arnoult & Lamotte (1968), Lamotte & Xavier (1981) and Lambiris (1988). Poynton & Broadley (1985a) even specify a SVL of up to 80 mm. Smaller frogs, concerning animals from Cameroon, were measured by Mertens (1938a); SVL: males 38 mm; females 57 mm) and by Perret (1966); SVL: males 40-49 mm; females 54-63 mm). Nieden (1915) mentions a specimen from Tanzania showing traces of a fourth claw.
Coloration: Dorsal parts of body and limbs drab olive with large black patches that are sometimes vaguely defined. The iris shows a silver-grey glimmer. The venter is whitish to orange yellow. Some darker patches occasionally appear on the throat and on the thighs. A single female had the belly scattered with black spots. Distinctive ventral designs were reported from Ghanian frogs (Poynton 1964c). According to Loumont (1984), the dorsal patches of animals from Tanzania, Malawi and Zimbabwe are often arranged in two longitudinal rows. Mertens (1955b) mentions a female from Tanzania whose venter showed smoky-gray patches and a young specimen whose venter was plain white. In alcohol the dorsum turns almost completely gray olive, and the original black patches are hardly visible. The venter turns gray white, and black spots remain visible.
Voice: So far, it has not yet been registered at Comoé National Park. According to Schiøtz (1963), the call sounds like a rather low "pink-pink" resembling the sound produced by a spoon knocking against a pan. According to Vigny (1979), animals from Malawi produce a sequence of rattling "trra-trra" calls lasting 0.15-0.21 sec, the dominant frequency being 1.1 kHz. She describes two types of calls. Picker (1983) has also published sonagrams. These calls lasts 0.15 to 0.20 sec, comprising 5-6 pulses (dominant frequency: 0.8-0.9 kHz). Wager (1986) describes the call as "turrr", comparing it to the sound produced by a pencil vibrating against a glass pane. According to Lambiris (1988), two soft calls per second are uttered under water. Passmore & Carruthers (1995) report short "metallic" calls produced under water at intervals of 0.15 seconds. The vocal apparatus of the male has been examined by Loumont (1981).
This account was taken from Rödel, M.-O. (2000), Herpetofauna of West Africa vol. I. Amphibians of the West African Savanna, with kind permission from Edition Chimaira publishers, Frankfurt am Main.
For references in the text, see here