A small ranid frog with a pointed snout. Adult males measure 14–20mm and weigh 0.3–0.8 g. Most of them measure from 17–18 mm and 0.5–0.7 g, respectively. Adult females measure 16–23 mm and weigh 0.4–1.2 g. Most of them measure 19–21 mm and 1.0–1.1 g, respectively. The mean index head width/SVL is 0.26 (s.d. + 0.03; 0.13-0.32; N = 57). No eyelid cornicle. Dorsum and central outer parts of thighs frequently covered with warts which may be quite distinct, particularly on the anterior part of the back. Warts on back usually large and rounded. Additional large comma-shaped warts converging towards the snout are found behind the eyes. However, the skin of the frogs is occasionally altogether smooth. This phenomenon is not a feature of different morphs, but apparently due to different physiological states, as one and the same individual may show both states. Tympanum visible but very small and feebly defined. Males with a subgular vocal sac which is not always clearly discernible. A small inner metatarsal tubercle. An outer metatarsal tubercle is present at the base of the fifth toe. Tarsal tubercle distinct. Webbing formula: 1 (0) or (0.5); 2 i/e (1–0) or (0.75–0.5) or (0.5–0); 3 i/e (1) or (1–0.5); 4 i/e(2) or (1.5); 5 (0.5) or (1). Hands not webbed. The tips of fingers and toes are at most feebly enlarged, but never forming discs.
Voucher specimens:SMNS 8957 1–48 + tadpoles; SMF 78651–56; SMNS 8990 1–2 Ananda, Ivory Coast.
The basic color of the dorsum varies from light gray brown, or darker brown to almost black. Almost black animals are found on darker soil, whereas those encountered on lighter substrates are beige. Breeding males may be bright yellow or green. Parts of the back, especially the warts, may be darker or even black. Dark transverse bands are always present on the thighs and shanks. A fine light mediodorsal line or a broad band, starting just at the snout tip or between the eyes may be present or lacking. These lines or bands may be white, orange, red or green. If they are red they usually show white or orange borders. Very rarely, the lines may be broken, sinus-shaped, zigzagged or ramified. The intensity of the colors apparently depends on the physiological status of the frog, e.g. the backs of breeding males with green dorsal bands may become plain green. However, this color may be "withdrawn" to the center of the back within a few minutes. A dark stripe starting at the snout tip extends above the nostrils to the eyes. Behind the eye, it crosses the tympanum and extends diagonally towards the belly, being occasionally interrupted above the base of the forearm. Another short dark band sometimes stretches from the groin to the back. The lower edges of the posterior thighs bear yellow longitudinal lines with black borders. These lines turn upward in the vent area, fusing occasionally above the anus. The throat and the rest of the venter are usually white; only a few females have throats mottled with black and white. The throats of breeding males are deep yellow. Black points occasionally appear on the throat and in the pectoral area (compare Ahl 1924a). The edge of the lower jaw often bears dark bars. The webs may be slightly pigmented. In alcohol, both the pattern and the warts often fade, so that it becomes difficult to distinguished them from other Phrynobatrachus species. However, the black lateral lines and the vertebral bands and lines usually remain visible, but being less distinct or faded.
The creaking advertisement call starts as a sequence of rapid pulses whose frequency ranges from 2.45–4.82 kHz. This phase lasts about 0.4 sec. After a short pause (0.2 sec), several notes comprising 3–7 pulses are uttered (frequency range: 1.88–5.14 kHz). The duration of a single note ranges from 0.33-0.44 sec, and that of the pauses separating the single pulses is 0.01–0.20 sec; those between the notes last 0.14–0.16 sec. 4–5 click sounds lasting 0.01 sec may precede the call. They are uttered at intervals of 0.23-0.43 sec. Their frequency ranges from 3.11–5.13 kHz. The duration of the longest call recorded was 17.55 sec. However, the call sometimes ends much earlier or even breaks off after the first phase. This happens quite frequently when the frogs call from their refuges during the day in the dry season.
To the human ear, the call of P. accraensis sounds quite similar. Schiøtz (1964c) has published a sonagram which he refers to this species. 3–5 notes, each comprising 1–3 pulses form units which are uttered at short intervals. These calls last up to 7 sec, with up to 35 pulses per second. The frequency intensity maximum lies between 2–4 kHz. Except for its duration, this call shows a structure which resembles, to a large extent, that of the P. latifrons I recorded. Schiøtz (1964c) recorded these calls in a savanna in Sierra Leone.
Böhme et al. (1994) describe the call of P. accraensis as a creaking sound ending with "overturning" clicks. Each sequence consists of 5–7 calls. The call of P. gutturosus is quite similar, but it begins with a long buzzing sound, whereas a few clicks are uttered towards the end.
300 to 1300 eggs are laid as a single surface layer, most frequently attached to vegetation in shallow water zones. The eggs are light sand yellow, and their diameter, incl. the jelly, is 2.2–2.3 mm (egg: 0.8 mm; for P. accraensis, see below).
The basic color of the very tiny tadpoles is dark red-brown. Their body shape is ovoid, and a feeble constriction is discernible on a level with the spiracle. The respective parts show a conspicuous red pigmentation. The tail fin is transparent or finely spotted, starting dorsally on the last quarter of the body and converging evenly towards the tip of the tail. On live animals, the serrated horny beaks seem to be very narrow. If the skin has contracted, e.g. on animals prepared for SEM photos, the beaks appear more voluminous. The keratodont formula is 1 / 1+1 // 2+2 or 1+1 // 2+2. These variations have been recorded within the offspring of a single pair. Additional yet very short and more caudal tooth rows may precede the papillae. All the tooth rows are arranged on the outer edges of dermal folds. The horny teeth have short broad bases. They bear a short semicircular "crown" with 4–5 tips. The mouth is surrounded by a single row of cone-shaped papillae followed by a variable number of filamentous ones. Freshly hatched tadpoles with external gills, do not yet possess oral discs. Their BL is 1.1–1.4 mm (TL: 3.7–4.1 mm). Reared in captivity for two months, they measured 6 mm BL, and 17 mm TL, possessing fully developed hind legs. A few days later, the first young frogs, of approx. 6 mm, left water. Tadpoles captured in ponds and possessing developed hind legs measured 8–10mm. According to my observations, the forelegs emerge at a BL of 7 mm (TL: 12 mm). Six weeks after the beginning of the rains, the first young frogs were observed on the edges of the ponds. They measured 7–7.5 mm, and their coloration was already as variable as in adult frogs.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Benin, Burkina Faso, Cameroon, Cote d'Ivoire, Gambia, Ghana, Guinea, Liberia, Mali, Nigeria, Senegal, Sierra Leone, Togo
Range: Because of the confusion of names, the exact range of this frog is difficult to define. The following countries have been quoted for P. "accraensis/latifrons": Senegal, Guinea, Sierra Leone, Mali, Burkina Faso, Ivory Coast, Ghana, Togo, Nigeria, Cameroon (Ahl 1924a, Loveridge 1941, Orton & Morrison 1946, Schiøtz 1963, 1964a, b, c, 1966, 1967, Lamotte 1966, 1967b, 1969, 1971, Perret 1966, Barbault 1967, 1974d, 1984, Euzet et al. 1969, Maeder 1969, Böhme 1978, 1994c, Barbault & Trefaut Rodriguez 1979b, Joger 1981, Frost 1985, Hughes 1988, Rödel 1995, 1996, 1998b, Böhme et al. 1996, Joger & Lambert 1997).
I have recorded P. latifrons in all habitats of the Comoé National Park. Typical P. accraensis were found in the rainforest zone of the Ivory Coast, both in areas disturbed by man and in those parts of the primary forest at the Tai National Park where vegetation happens to be rather scanty (e.g. on Inselbergs). Hughes (1988) quotes P. accraensis for any habitat in Ghana, but this probably shows that he does not distinguish savanna and forest forms. Schiøtz (1967) considers P. accraensis a "farm bush" element of the fauna, i.e. occupying an intermediary position between savanna and forest species. Lamotte (1967b) quotes both savanna and forest locations, but the latter are reported to prevail. Different types of water bodies are colonized at different seasons.
Life History, Abundance, Activity, and Special Behaviors
During the dry season, P. latifrons lives on the river banks and near those forest ponds which still contain some water. Whereas the frogs inhabiting forests, particularly the humid tracks of large mammals, are equally diurnal, those found on the river banks are strictly nocturnal at such times. During the day, they usually seek refuge under stones and dead wood or in crevices on the very edges of water bodies. While day temperatures may reach 40 °C or more, the temperature in those day refuges proved to be comparatively moderate, i.e. 35 °C at most. At night, the frogs forage for prey in a very limited area bordering open water, feeding mainly on arthropods. Some individuals always seem to hunt in the same area. Complexly structured bank sectors usually harbor more frogs. Habitat choice and activity period are apparently humidity dependent (Rödel 1995). In the dry season, the P. latifrons populating river banks are most active between nightfall and 10 h p.m. and in the early hours of the morning. After rainfall, many individuals leave the river area. Having crossed the gallery forest, they reappear at savanna ponds, now filled with water. I only rarely found this species in the crevices developing at the bottom of dried-up water bodies. If the ponds are far away from the river, however, it cannot be excluded that the frogs mainly survive in such crevices. Migration is triggered by rainfall. The habitat shift after rainfall may have several reasons. First, rising water level of the river may directly threaten the frogs. Secondly the soil is much more humid after rain. It is therefore not necessary to restrict the foraging area to the river’s edge. And lastly, with the filling of the savanna ponds P. latifrons may begin its reproduction phase. During extended dry periods, P. latifrons is found more frequently in the forest, particularly on the edges of pools and on riverbanks. At least some females apparently contain mature eggs during the dry season. The males call sporadically. However, I never found spawn at that time. I could not verify whether the frogs also reproduce in the forest ponds where they are frequently heard during the early rainy period. I never captured their tadpoles in these ponds. The forest habitats seem only to serve as refuges, being colonized when the savanna becomes too dry. Most probably, savanna ponds are only visited by those female P. latifrons which are about to lay their eggs. Males considerably outnumber females at these ponds. However, according to Lamotte & Xavier (1981), P. accraensis never leaves the immediate area of its ponds. P. latifrons is very common at most savanna ponds where the frogs have proved to be diurnal, too. Considerable choruses may be heard even during hot sunny days. However, they usually call when the sky is clouded, or before and after rainfall. At night, their voices are drowned out by the voices of other frog species. At night they only call when other species are less common. During the day, single males will call from concealed calling sites on the floor, between tufts of grass or from floating aquatic plants. At night, they are also met on the plain ground or on grass leaves, up to 30 cm above the soil. The yellow vocal sac may be an additional visual cue during calling. Other ranid frogs with yellow vocal sacs (Phrynobatrachus alleni, unpubl. data; Pyxicephalus adspersus, Picker 1983a) likewise call during daytime.
At Comoé National Park, P. latifrons is the only species that regularly spawns during the day. The amplectant pairs perform a headstand underwater while spawning. The female clings to aquatic plants during egg laying. In this position, a single egg layer is spread over the water surface (Linsenmair, pers. comm.). As a consequence of this behavior, the film is almost always attached to grass. Clutches are also found even when it does not rain at all for a longer period. However, the frogs usually spawn after rainfall. The intensity of precipitation apparently plays a minor part, and it does not always trigger reproduction. Many pairs spawn simultaneously. The egg films are often concentrated in a few areas of the pond. Shallow shady sites bearing a rich vegetation are preferred spawning sites. The dorsal warts of breeding males seem to be more developed than those of females and non-breeding males.
The frogs prey on anything they can overpower. Their diet mainly consists of arthropods (Rödel 1995). One collected male was swallowing a Kassina tadpole measuring 15 mm while still in the net. At Lamto, adult P. accraensis mainly preyed on ants (Barbault 1974d).
P. accraensis reaches sexual maturity at the age of 4–5 months, living only for further two months. Females measure about 19 mm (maximally 25 mm). They are likely to produce two clutches consisting of 267 ± 130 eggs with a mean egg diameter of 0.9 mm (N = 93; Barbault & Trefaut Rodriguez 1979b, Barbault 1984). At Lamto, population sizes have proved to vary considerably during a given year. This phenomenon was explained by them as the succession of two generations within the same year. According to my own observations, however, varying densities may also be due to the humidity dependent migrations mentioned above. However, in January 1999 I only captured juvenile P. latifrons, P. francisci and P. gutturosus at the edges of savanna ponds. This may indicate that in Comoé National Park at that time all the adults had already died. Contrary to H. nitidulus juvenile Phrynobatrachus continued feeding throughout the dry season (Rödel 1995), thus maturing for the beginning of the next rainy season.
The larvae usually prefer the bottom of the deeper zones of ponds, as well as more vegetated sites. They may be found throughout the rainy season (Rödel 1998b). As they proved to grow much slower in captivity than in the field, in spite of otherwise similar conditions, they have possibly specialized on certain food items. The function of their filamentous papillae has not yet been examined.
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
Rödel, M. O. (2000). Herpetofauna of West Africa, Vol. I. Amphibians of the West African Savanna. Edition Chimaira, Frankfurt, Germany.
Written by M.O. Roedel (roedel AT biozentrum.uri-wuerzburg.de), Post-Doc at the University of Wurzburg, Department of Animal Ecology and Tropical Biology, Wurzburg, Germany
First submitted 2001-05-04
Edited by Arie van der Meijden (2002-01-12)
Species Account Citation: AmphibiaWeb 2002 Phrynobatrachus latifrons <http://amphibiaweb.org/species/3784> University of California, Berkeley, CA, USA. Accessed Nov 16, 2018.
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Citation: AmphibiaWeb. 2018. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 Nov 2018.
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