A big, long-legged ranid with a pointed snout and distinct dorsal ridges. SVL of males: 43–57 mm; females: 43–68 (–72?) mm. The large clearly visible tympanum reaches 0.7–0.9 of the eye diameter. Two pairs of continuous dorsal ridges. A short ridge between the outer dorsal ridge and the dorsolateral one. Occasionally this ridge may be absent. Some larger warts on the flanks. Males with paired lateral vocal sacs whose slits run from the end of the lower jaw directly to the base of the arm. Thigh length is 0.45–0.62 of the SVL; the lower leg measures 0.58–0.65, and the foot, incl. longest toe, reaches 0.73–1 of the SVL. Fingertips and toe-tips not expanded. The inner metatarsal tubercle is tiny, reaching just 0.2–0.4 of the shortest toe length. Webbing formula: 1 (0.5) or (1), 2 i/e (1–0.5) or (1.5–0.5), 3 i/e (1.5–0.5) or (1–0.5), 4 i/e (2) or (1) or (0.5), 5 (0.25) or (0.5) or (1). The ventral skin is granulated. The legs of larger individuals are proportionally longer (Guibé & Lamotte 1958a). Patterson & McLachlan (1989) give a median adult SVL of 40.5 mm.
Coloration: The back has a uniform brown basic coloration with a bright vertebral band beginning at the snout tip. The color of this band may be white, beige, yellow, orange or green. Some individuals may lack this band. Several black spots are present on the dorsal ridges. The dorsolateral ridges are light. Animals showing a uniform dark coloration with a fine pale vertebral line are reported to exist, too. The brown tympanum has a narrow pale border and a somewhat paler center. It is surrounded by a dark temporal triangle. The region between nostril and eye is also dark. The vocal sacs are gray. Several white patches occasionally appear on the flanks. The dark bars on the thighs are present only on the anterior part. A thin yellow longitudinal line with black borders runs along the posterior part of the thighs. The light brown shanks invariably show a narrow light longitudinal line. A similar marking may appear on the thighs. The upper lip is bright white, and this coloration is likewise present on the infratympanic ridge stretching to the upper arm. If black bars are present on the shanks, they are usually restricted to the posterior part. Black spots are present on the ventral border of the lower jaw. The throat may be mottled black. The rest of the venter is white to yellowish. The ventral parts of the extremities are white-orange.
Voice: Amiet (1974b) describes the advertisement call as a low nasal "hoin". It resembles the call of P. bibroni, but seems to be lower and "slower". Lambiris (1989) describes a short and very nasal "quack" usually followed by several click sounds. A sonagram has been published by Schiøtz (1964c), too. According to Perret (1979b), the calls of frogs from South, East and West Africa are identical. The call of Serengeti frogs described by Van Den Elzen & Kreulen (1979) consists of 12 pulses (Amiet/Cameroon: 22) per call and lasts about 0.12 sec (Amiet: 0.15–0.2 sec). The dominant frequencies in Tanzanian frogs are 0.5–1.2 kHz and 2.3–3 kHz (Amiet; 1.3–2.3 kHz). According to Passmore (1977), the call of South African frogs comprises 16 pulses and lasts 0.17 sec (dominant frequency: 2.3–3 kHz). The differences might be, at least partially, temperature-dependent. Akef & Schneider (1995) described the advertisement call in Egyptian P. mascareniensis. Their frequency range was 0.25–3.5 kHz. The calls were uttered in long continuous series from 5–10 min. Variation in some calling parameters was temperature dependant.
Similar species: Easily distinguished from Hoplobatrachus tigerinus by the more continuous dorsal folds rather than rows of tubercles.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Cameroon, Central African Republic, Congo, the Democratic Republic of the, Egypt, Eritrea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Madagascar, Malawi, Mauritania, Mozambique, Namibia, Nigeria, Rwanda, Senegal, Seychelles, Sierra Leone, South Africa, Sudan, Tanzania, United Republic of, Zambia, Zimbabwe
Range: This species has not yet been found at Comoé National Park. According to Frost (1985), it inhabits an enormous area stretching from Egypt to Sierra Leone, Natal and Madagascar. "P. mascareniensis"-records have been published for the following countries: Senegal, Guinea Bissau, Sierra Leone, Guinea, Liberia, Ivory Coast, Ghana, Nigeria, Cameroon, Gabon, R.D. Congo, Central African Republic, Egypt, Ethiopia, Eritrea, Sudan, Kenya, Tanzania, Zanzibar, Rwanda, Malawi, Zambia, Zimbabwe, South Africa, Namibia, Madagascar (Müller 1885b, Günther 1895, Nieden 1903, 1910b, 1915, Boulenger 1906, 1910, 1919, Lönnberg 1910, Chabanaud 1921, Noble 1924, Loveridge 1925, 1929, 1930, 1933, 1936, 1941, 1955a, c, Scortecci 1929, Parker 1930, 1936?a, b, ?c, ?Witte 1934, 1941, ?Sanderson 1936, Mertens 1938a, ?b, 1940, 1955b, ?Monard 1940, Paulian & Vilardebo 1946, Romer 1953, Guibé & Lamotte 1955a, 1957, Perret & Mertens 1957b, Taylor & Weyer 1958, Schmidt & Inger 1959, Inger & Marx 1961, Schiøtz 1963, 1964a, b, c, 1967, 1968, Euzet et al. 1966, Perret 1966, 1979b, Lamotte 1967a, b, 1971, Stewart 1967, Walker 1968, Maeder 1969, Perret & Amiet 1969, Urban 1969, Broadley 1971, Drewes 1972, Stevens 1974, Amiet 1975, Böhme 1975, 1978, 1994d, Passmore 1977, Miles et al. 1978, Van den Elzen & Kreulen 1979, Joger 1981, 1982, 1990, Murith 1981, Barbault 1984, Branch 1988, Hughes 1988, Lambiris 1988, 1989, Channing 1989, Patterson & McLachlan 1989, Rödel 1990, 1996 Poynton 1991, Fischer & Hinkel 1992, Channing & Griffin 1993, Simbotwe & Mubemba 1993, Glaw & Vences 1994, Pickersgill 1994, Passmore & Carruthers 1995, Largen 1997a, 1998).
Habitats: This species inhabits humid savannas and forests (e.g. Amiet 1975). According to Böhme (1994d), it is a savanna species but invades the rainforest via forest lanes. Perret (1979b) reports on similar habitats. He wrote that this frog prefers humid savannas and also invades degraded forests. In Kenya, it is found at elevations of up to 2000 m. According to Lamotte (1967b), it is a forest species. According to my own observation, this holds true for the Ivory Coast. However, it rarely penetrates true rainforest. I found it only at the forest border or on clearings.
Occurs from sea level up to over 2000 m elevation in various habitats.In Africa it lives in agricultural areas, rice fields, secondary vegetation with tall herbaceous vegetation and marshy areas, and is often found near large lakes, rivers and other wetland habitats (including irrigation canals). In Madagascar and the Seychelles, it lives in extremely varied habitats, including rainforest (marginally), dry forest, fields, savannahs, grassland, and urban areas (Rodel et al. 2008).
Life History, Abundance, Activity, and Special Behaviors
Spawn: At Lamto, Ivory Coast, females produce 1079 eggs with an egg diameter of 1.1 mm (N = 6; Barbault 1984).
Tadpoles: The keratodont formula of the dark gray-brown tadpoles is 1 / 1+1 // 2, very rarely 1 / 2 + 2 // 2 (Perret 1966). The dorsum is scattered with bright brownish spots with a metallic glimmer. The tail length is three times its height, and three times the body length. It is very pointed. The beaks are serrated. Mertens (1938b) mentions a row of papillae only for the lower lip. Lamotte & Perret (1961a) describe papillae that are arranged in one to two rows. Even more rows are present in the corners of the mouth. A rostral gap is present, as in most other tadpole species. According to the above authors, the tail is comparatively short. The forelegs of a tadpole measuring 37mm (TL; BL: 16 mm) were about to emerge (Mertens 1938b, Guibé & Lamotte 1958a, Lamotte & Perret 1961a). Froglets measure 19 mm (Patterson et al. 1989).
Biology: According to Mertens (1938b), the very long breeding period in Cameroon is interrupted only by the dry season. Lambiris (1989) reports on single males calling between vegetation on the edges of ponds. Referring to the coastal region of the Ivory Coast, Murith (1981) writes that P. mascareniensis breeds before and after the rainy period, appearing at the savanna ponds two to three times per year. Compared with my preliminary observations on this species in Tai National Park this statement seems to be very doubtful. In Malawi, these frogs reproduce during and after the rainy season (Stewart 1967). Spawning sites include temporary ponds, car tracks, road ditches and swamps (Mertens 1938b, Schiøtz 1964c, Perret 1966, Amiet 1974b, Hughes 1988). However, large water bodies such as rivers and lakes are also quoted (Patterson & McLachlan 1989, Fischer & Hinkel 1992). Males call partially submerged between vegetation (Van den Elzen & Kreulen 1979). Lambiris (1989) found these frogs mainly near waters. In Namibia males call from the bank under vegetation or exposed on bare soil or while floating clinging to vegetation (Channing 1989, Channing & Griffin 1993). According to Akef & Schneider (1995), in Egypt calling males were rare in large permanent water bodies. When calling they float on the water surface or sit on the ground. They show little aggressive behavior. The distance between calling males was 50–80 cm. The distances in small pools were smaller than in larger ones.
The frogs are active both during the day and at night, preying on locusts, beetles and aquatic invertebrates. According to Inger & Marx (1961), their diet includes mainly, but not exclusively, terrestrial prey. In particular, these authors quote beetles, orthopterans, cicadas, dragonflies, ants, butterflies and amphibians (both tadpoles and young frogs).
Breeding takes place in puddles, ditches, and ruts (Rodel et al. 2008).
Trends and Threats
Least Concern: wide distribution, tolerance of a broad range of habitats, and large population. It occurs in many protected areas (Rodel et al. 2008).
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.
Also taken with permission from Vences and Glaw (2007).
Glaw, F., and Vences, M. (2007). Field Guide to the Amphibians and Reptiles of Madagascar. Third Edition. Vences and Glaw Verlag, Köln.
Rödel, M. O. (2000). Herpetofauna of West Africa, Vol. I. Amphibians of the West African Savanna. Edition Chimaira, Frankfurt, Germany.
Rödel, M. O., Largen, M., Minter, L., Howell, K., Nussbaum, R., Vences, M., and Baha El Din, S. (2008). Ptychadena mascareniensis. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. . Downloaded on 14 April 2009.
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 2001-05-07
Edited by Henry Zhu (2009-05-06)
Species Account Citation: AmphibiaWeb 2009 Ptychadena mascareniensis: Mascarene ridged frog <http://amphibiaweb.org/species/4941> University of California, Berkeley, CA, USA. Accessed Oct 16, 2017.
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Citation: AmphibiaWeb. 2017. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 Oct 2017.
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