Comprehensive Description

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Description

Diagnosis: Large, plump frog; typical color pattern; yellow dorsolateral ridges are broad and flat.

Description: A large, plump ranid with comparatively short hind legs. The largest male in Comoé National Park measured 77.4 mm, the largest female reached 62 mm (SVL). However, males are normally smaller than females. The snout is moderately pointed. The tympanum is clearly visible, reaching about 0.8 of the eye diameter. Males with paired lateral vocal sacs. Males with large glands on the ventral side of the upper arm. Distinct flat, large dorsolateral ridges running from the posterior eye border to the end of the body. Skin with large flat warts on the flank and posterior back regions, but smooth or finely granulated otherwise. Sturdy forelegs; thighs and lower legs measure just 0.38–0.45 of the SVL. The foot, including the longest toe, measures 0.7 of the SVL. Toes without discs; toe tips never larger than the subarticular tubercles. The inner metatarsal tubercle measures 0.4 of the shortest toe length. An outer metatarsal tubercle may be present. Webbing formula: 1 (1) or (0.5), 2 i/e (1–0.5), 3 i/e (2–1) or (1.5–1), 4 i/e (2), 5 (0.5).

Voucher specimens: SMNS 8949 1–2 + tadpoles; SMF 78625.

Coloration: The basic body color varies from drab pale brown to dark brown. The dorsum appears comparatively uniform, showing just several paler yellow spots in the anal region and on the thighs, producing, a mottled pattern. The iris is golden to orange. A pale yellow to pale orange stripe runs from the nostril across the eyelid and along the dorsolateral ridge to the body end. On the body, these slightly prominent bands are lined by dark brown to black borders. The upper lip is white, stretching further to the groin as a line of the same color with straight to slightly undulating black borders. The part of the snout between the above-mentioned lines and the tympanum is dark brown. The flanks show the same color as the back, bearing several flat yellowish warts with dark borders. Similar markings appear in the groin region, comprising somewhat larger yellow patches with dark borders. On the thighs, the black borders dissolve, forming dark meanders on a pale background. The latter is white on the inner faces of the thighs, but olive to brown on the outside. The lower legs are divided into two rather different sections by a pale longitudinal stripe with dark borders. The dorsal part is more or less uniform brown, whereas the lower sector is mottled in black or yellow brown. The feet and arms are light colored. Dark pigments are present only in the axillary region. The venter is whitish to light gray, with only the lateral regions of the belly and hind limbs being mottled with dark. Coloration in alcohol is generally similar to live coloration. However, yellow pigments usually turn white. In general the markings tend to fade out.

Voice: This frog regularly produces two different calls whose exact functions are still unknown. However, they are assumed to be advertisement calls. The more common one is a high-pitched hooting or barking "huhoot" lasting about 0.36–0.57 sec whose frequency ranges from 0.2–3 at the beginning to 1.80–2.75 kHz at the end. The second call is a long low grunting sound lasting 0.85–1.30 sec, consisting of many short pulses which lasts 0.01 sec, and are separated by intervals of 0.03 sec. At first, two different harmonies between 0.4–0.8 and 1.6–2.5 kHz seem to be produced (the sonagrams are far from perfect); however, they fuse within 0.4 sec, and the frequency now ranges from 0.4 to 2.8 kHz. The calls are often uttered irregularly, and the pauses occasionally last several minutes. Males obviously stimulate each other by their calls. Amiet (1973a) does not believe that the two calls have different functions. For Nigeria, Walker (1967) only mentions the "barking" sound. Perret (1977b) does not report on different calls either.

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

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