Family Bufonidae

Bufo maculatus Hallowell, 1854

Flat-backed Toad, Gestreepte Skurwepadda (A)

By R.C. Boycott

Currently accepted name: Sclerophrys pusilla (Mertens, 1937)
Red listing status: Least Concern (IUCN, 2016)

Photo by Wilkinson J H, 2009. URL: FrogMAP: 228

Distribution

B. maculatus is probably the most widespread toad in Africa, occurring in West Africa, East Africa and southern Africa. Although it is generally distributed through the savannas of sub-Saharan Africa (Poynton and Broadley 1988), there are records from further north at Luxor in the Nile valley, Egypt (Stewart 1967). The species is found in northeastern South Africa, reaching its southern limits in Swaziland and northern KwaZulu-Natal. In Swaziland it occurs at altitudes of 90–790 m, and in South Africa, from 40–1700 m (Jacobsen 1989). These toads occur quite far inland in Swaziland and adjacent South Africa, where their distribution range extends up the larger river valleys, including the Nkomati, Mlumati, Elands, Olifants and Limpopo rivers.

This species is easily identified by its call. The atlas data are accurate but incomplete.

Habitat

In the atlas region, this species inhabits various vegetation types within the Savanna and Grassland biomes, on the Zululand coastal plain (Lambiris 1989a), in the Swaziland lowveld and middleveld (Boycott 1992), and in the lowveld and bushveld of northeastern South Africa (Jacobsen 1989). It is usually associated with riverine habitats: in Swaziland the species is almost always associated with medium and large rivers and is seldom found at pans, borrow pits or dams. In Ivory Coast, the species occurs in both forest and savanna habitats.

Breeding habitat is riverine. During the dry season in Ivory Coast, the species breeds alongside rivers in small, shallow inlets and puddles created by rising and falling water, as well as in rock-pools, while in the wet season it moves away from rivers to forage in gallery forest or forms new choruses in savanna, usually in periodic brooks (Rödel 2000).

At Pafuri, in the north of Kruger National Park, adults and juveniles have been found sheltering under rocks, logs, piles of dead leaves and branches, and building debris (H. Braack pers. comm.).

Life history

Breeding takes place from September to January in Kruger National Park (H. Braack pers. comm.), while in Ivory Coast it occurs throughout the year (Rödel 2000). Some authors recorded an increase in breeding activity during dry periods (Channing 1989; Rödel 2000).

In Swaziland, and elsewhere in the atlas region, the species calls from well-concealed positions amongst reeds, grass or rocks, next to or in rivers and streams where there is fast-flowing water (Jacobsen 1989; pers obs.). In Zimbabwe, calling from exposed sites has been observed (Lambiris 1989b). Calling takes place at night and during the day.

The calls are often antiphonal, with individuals calling at slightly different pitches so that alternate calls are readily distinguishable (Pienaar et al. 1976; Lambiris 1989a). Females approach calling males and make contact prior to amplexus (Channing 2001). Amplexus is axillary. Wager (1986) recorded eggs 1.2 mm in diameter in a single jelly tube 3 mm thick, while Tandy and Keith (1972) asserted that all African Bufo species produce two egg strings. In Ivory Coast, B. maculatus produces two egg strings simultaneously from the cloaca, containing 2000–8000 eggs, 1.5 mm in diameter (Rödel 2000). The egg strings are deposited at the bottom of a pool or wound around stones or twigs. Tadpoles reach metamorphosis within six weeks in captivity and in as little as two weeks in the wild (Rödel 2000).

Sandflies are known to feed on the blood of B. maculatus (Braack et al. 1981), while juveniles and adults are preyed on by the Common Night Adder Causus rhombeatus (Pienaar et al. 1976). In Ivory Coast, the Spotted Night Adder Causus maculatus and a scorpion Pandinus imperator were recorded as predators (Rödel 2000). In savanna pools in Ivory Coast, tadpoles of the Crowned Bullfrog Hoplobatrachus occipitalis feed on the tadpoles of B. maculatus (Rödel 2000), while in the atlas region they are sometimes taken by Mozambique Tilapia Oreochromis mossambicus (H. Braack pers. comm.). Adults feed mainly on ants, but also on beetles and alate termites (Rödel 2000).

Conservation

B. maculatus is widespread and common, occurring in several national parks and other protected areas in South Africa and Swaziland (Jacobsen 1989; Lambiris 1989a; Boycott 1992). Much of its habitat is well protected in cattle and game farming areas; consequently the species is not threatened.

Current distribution map

Undated records;  pre-1996;  1996 to 2002;  2003 to present