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Diagnosed as a small ranid-like frog; males with lengthened third finger; no webbing; dark hour-glass pattern on back (in most specimens).
A small compact frog with a blunt snout. The head width almost equals a third of the SVL. Males measure 19-27 mm and weigh 0.60-1.05 g. SVL of one female measured was 31 mm (weight: 2.69 g). Frétey and Dewynter (1998) cite a gravid female of 34 mm SVL from Gabon. Males have a single subgular vocal sac. The tympanum is clearly visible, slightly concave and large; it measures 0.9 of the eye diameter. Skin almost smooth or granular with numerous small round warts. Long forelegs. Neither the fingers nor the toes are webbed. Males have extremely long third fingers. As a result, the hand is almost as long as the thigh or shank. The inner metatarsal tubercle reaches 0.7 of the length of the shortest toe. Tips of fingers and toes are not enlarged.
Voucher specimens: SMNS 8961 1-3.
I assume that the color patterns I am going to describe represent various types of one and the same species. However, it cannot be excluded that several species of Arthroleptis occur at Comoé National Park. The basic color of the back varies from light beige to light or intensive orange to copper-red. Whereas the snout tip is always light colored, showing the basic color of the back, a dark figure usually starts between the eyes and stretches to the vent area. This marking most frequently resembles an hour-glass. Breeding males may be very dark or even black. In this case, the dorsal marking is almost invisible. We once found a female whose rectangular dorsal dark marking was interrupted by a light vertebral line. The backs of other specimens were plain copper-red, and this color also extended to the dorsal areas of the flanks and to the dorsal parts of the extremities. Only a short streak behind the tympanum and the upper part of the latter were black. A few black spots are also present on the flanks. In all other animals, the black dorsal markings were clearly separated from the color of both the lateral part of head and the flanks. The latter are dark gray to black. The hind legs are of the same color, lightened only by a few reddish spots. The forelegs share the basic coloration of the back with several black spots and strokes. At the border, from the flanks to the venter, the dark marking gradually fragments, and some white spots produce a mottled pattern. The belly is white to gray. The inguinal area is often yellow. Some white spots are present on the dark lower lip. The throat of males is dark violet. The iris is mottled in gold and black. Loveridge (1955a) describes specimens from the Ivory Coast showing hour-glass markings, vertebral lines and bands. The dark markings fade slightly on animals preserved in alcohol. The male throat turns dark gray,and the venter becomes gray.
The high-pitched warbling call lasts 0.77-0.90 sec. It consists of 5-8 notes comprising many short pulses. Each of these notes last 0.04-0.12 sec, and their length increases according to that of the call. The frequency of the advertisement call ranges from 3.5-5.8 kHz. For humans, the call strongly resembles those of some crickets and that of Phrynobatrachus calcaratus. Calls of the genus Arthroleptis have rarely been published.
The call which Schiøtz (1964c) assigns to Arthroleptis sp. does not correspond to the calls uttered by the frogs at Comoé National Park. In 1966, he published a call labeled Arthroleptis taeniatus. The latter species is supposed to be a synonym of A. poecilonotus (Perret 1991b). However, the sonogram clearly differs from the calls of the Comoé National Park frogs.
A clutch consists of large eggs rich in yolk which are laid in small cavities in the soil. According to Barbault and Trefaut Rodriguez (1979a) and Barbault (1984), females produce 2-3 clutches comprising 10-30 eggs each (x = 21; s.d. + 8). The egg diameter is 2.9 mm.
Development takes place entirely within the egg and fully developed young frogs finally hatch out. The SVL of frogs measured in mid-to-late July ranged from 8 to 9.5 mm, and a young frog captured in early June measured just 7 mm. Young A. poecilonotus measured 12 and 13 mm and weighed 0.14 and 0.19 g, respectively. Young frogs already show the hour-glass pattern of adult animals.
Lamotte and Perret (1963b) report on clutches they found in manioc and peanut plantations towards the end of the smaller rainy season (June/July). 20-25 eggs measuring 2-6 mm were laid in small cavities. Thirteen days later, pigmented eyes begin to develop on the white embryo, and the extremities gradually develop. After 15-20 days, the jelly capsule is broken through by vigorous movements of the head and extremities, and the young frogs hatch. They still have tiny tails, and the remaining yolk can be seen through the transparent belly. Their snouts are more rounded than in adult frogs. In addition, their skeleton has not yet ossified completely. Direct development has also been observed in A. crusculum (Guibé and Lamotte 1958c).
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