© 2016 Daniel Portik (1 of 12)
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.
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).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Benin, Cameroon, Congo, Congo, the Democratic Republic of the, Cote d'Ivoire, Equatorial Guinea, Gabon, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Sudan, Togo, Uganda
At Comoé National Park, the frogs are mainly associated with gallery and island forests, while moist savannas bearing a rich vegetation are also inhabited. In Lamto, according to Lamotte (1967), this species is more common in the savanna. However, this frog is generally considered as a species inhabiting rainforests, swamp forests and gallery forests (e.g. in Noble 1924, Lamotte and Perret 1963b, Schiøtz 1963, Hughes 1988, Böhme 1994c) or degraded forests and clearances (Amiet & Perret 1969). Savanna habitats have been occasionally quoted (Lamotte & Perret 1963b, Walker 1968, Amiet 1975, Hughes 1988). On Mt. Cameroon, the species is reported to occur at elevations of 1000 m above sea level. (Mertens 1939).
Life History, Abundance, Activity, and Special Behaviors
This species is reported to spend the dry season underground (Lamotte 1967b). At Lamto, the frogs mature when they are aged 3–4 months, and they usually live up to six months. Population density is highly variable, depending mainly on the amount and distribution of the precipitation of the previous year. However, in Lamto these frogs occur in high densities. The two generations of a year reproduce from March to June and from August to November (Barbault 1972, 1984; Barbault and Trefaut Rodriguez 1979a).
Because of its short life-span and the 2–3 clutches produced by a single female, this species has been characterized as an "r-strategist" (producing numerous small offspring, so that comparatively little energy is invested in each) by some authors. However, in view of its low reproductive potential, the considerable amount of energy spent on the production of larger eggs that are rich in yolk, and the comparatively large young, this species deserves to be categorized as a "K-strategist".
According to Loveridge (1955a), gravid females are found between March and July. At Lamto, S. poecilonotus is said to feed mainly on ants and termites (Barbault 1974). Most probably, the reports of Parker (1936c) and Sanderson (1936) do not refer to this species or even genus. For example, Sanderson (both authors are reporting on the same frogs) reports that these frogs are also found in lentic water where it breeds, as indicated by swarms of young frogs. In addition, this frog was said, by these authors, to prefer arid habitats. Amiet (1989) describes two males struggling for a calling site.
Rödel, M. O. (2000). Herpetofauna of West Africa, Vol. I. Amphibians of the West African Savanna. Edition Chimaira, Frankfurt, Germany.
Written by M.O. Rödel (roedel AT biozentrum.uri-wuerzburg.de), University of Wurzburg, Department of Animal Ecology and Tropical Biology, Wurzburg, Germany
First submitted 2001-05-08
Edited by Kellie Whittaker (2008-01-18)
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