A medium-sized toad with a blunt rounded snout. Males reach 52–86mm SVL, females 55–87 mm. The head is much wider than long. The nostril is situated closer to the snout tip than to the eye. The eye diameter surpasses the snout length. The well-defined tympanum is about 0.6 times the size of the eye diameter. These toads have moderately developed, more or less kidney-shaped parotid glands whose anterior border, above the tympana, is very vaguely defined, bearing just a few thorns. An infratympanic ridge runs from the corner of the mouth to the armpit. Males have single subgular vocal sacs. The dorsum has numerous conical warts, each of which bears a black spine. These toads may contain some rather rounded warts, bearing various spines, and they are arranged along the vertebral line on the last third of the back. Spines are usually less developed on females. Males have prominent elongate glands on the hidden surfaces of their forearms, and during the breeding season, black nuptial pads are present on the first three fingers. The palmar tubercles are covered with many asperities which are conical but not thorny. The inner metacarpal tubercle is smaller than the outer one, one half being covered by a black nuptial pad. Hind limbs have sharp-edged tarsal folds and modest webs, without warts. Both an inner and an outer metatarsal tubercles are present, the former being larger, ovoid and prominent. The contain very few additional subdigital tubercles. The ventral skin is roughly granular, without asperities. According to Tandy et al. (1976), the sex-dependent size dimorphism is lacking in some populations. Animals from Cameroon apparently reach somewhat larger sizes (Hulselmans 1977b). Salvador (1996) gives 97 mm SVL for females.
Coloration: The cream to pale gray or chocolate-brown back bears six pairs of symmetrical patches, the fourth pair being the largest. These spots are all bordered in black. Additional asymmetrical dark patches may be present. Very rarely, those patches fused into each other. White spots or vertebral lines are rarely present. The basic coloration of the extremities is similar to that of the back, usually bearing dark patches of irregular shape. The black spiny tips of the warts contrast sharply with the paler background. An indistinct brown canthal strip is present. Starting at the posterior end of the parotid glands, an indistinct clear strip runs half-way across the flanks. The venter is cream colored, being somewhat mottled on some males. The throats of females show a light pigmentation, those of males a dark one. They also contain scarlet meandering markings on the outer parts of the thighs. In alcohol, the red pigments may disappear. The coloration of females is more contrasting, and they never show the above-mentioned scarlet markings. The webbing is flesh-colored.
Voice: Lasting about 0.36–0.40 sec, the call has a dominant frequency of 0.88 kHz. It comprises a complex sequence of pulses which are said to resemble the "hoot" uttered by a big owl. The advertisement call varies according to the toad’s size (Tandy et al. 1976). According to Hulselmans (1977b), a sequence comprises 12–21 single calls, each lasting 0.25–0.35 sec, and being made up of 47–73 pulses. Hulselmans (1977b) mentions three dominant frequencies (0.57–0.60, 0.73–0.80 and 0.89–0.97 kHz). He also reports on highly variable individual calls.
Distribution and Habitat
Country distribution from AmphibiaWeb's database: Algeria, Burkina Faso, Cameroon, Chad, Djibouti, Eritrea, Ethiopia, Guinea, Kenya, Libyan Arab Jamahiriya, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Somalia, Sudan, Tanzania, United Republic of, Uganda, Western Sahara
Range: So far, this species has not been documented at Comoé National Park. According to Frost (1985), its range comprises Africa south of the Sahara, with Tanzania forming the southern limit. In particular, it has been recorded form the following countries: Senegal, Guinea, Sierra Leone, Mali, Algeria, Niger, Cameroon, Chad, Ethiopia, Eritrea, Somalia, Kenya, Uganda, Tanzania (Laurent 1965, Amiet 1973a, Böhme 1975, Tandy et al. 1976, Hulselmans 1977b, Joger 1981, 1982, Lanza 1981, ?Zug 1987, Salvador 1996, Joger & Lambert 1997, Largen 1997a, 1998, Poynton 1998).
Habitats: Very arid savannas with 299–1000 mm precipitation (x = 578 mm) and mean year temperatures of 16–29.2 °C (x = 23.4 °C) (Tandy et al. 1976, Hulselmans 1977b, Lanza 1981). The range of this species even includes the massifs of the central Sahara. In desert areas it colonizes oases (Salvador 1996). It is rather doubtful whether the Guinea savanna is equally colonized by this toad. According to Joger (1981), potential habitats include dry river beds, oasis gardens and watering places.
Life History, Abundance, Activity, and Special Behaviors
Spawn: Unknown. If the B. gutturalis mentioned in Zug (1987; this author based his determination on Tandy & Keith 1972, compare synonyms) happens to be B. xeros, their eggs show a diameter of 0.9–1 mm when still in the ovaries. The animal pole is darker.
Tadpoles: Detailed descriptions are lacking. According to Salvador (1996), tadpoles reach 34 mm TL. Metamorphosed froglets measure 10.5–15 mm.
Biology: According to Salvador (1996) in northwest Africa, B. xeros is active from September to March. There it is active during night-time. In the breeding season, which lasts from September to October, it is diurnal, too. The diet of this toad includes arachnids and insects, mainly coleopterans. Tandy et al. (1976) describe a half-submerged male calling from a pond within the river bed. Hulselmans (1977b) reports on calling males sitting near or in the water.
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 2001-02-26
Edited by Vance Vredenburg (2002-01-14)
Species Account Citation: AmphibiaWeb 2002 Sclerophrys xeros <http://amphibiaweb.org/species/315> University of California, Berkeley, CA, USA. Accessed May 24, 2019.
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Citation: AmphibiaWeb. 2019. <http://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 24 May 2019.
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