Family Brevicipitidae

Breviceps verrucosus Rapp, 1842

Plaintive Rain Frog, Klaende Reënpadda (A), Klaende Blaasoppadda (A)

By L.R. Minter

Currently accepted name: Breviceps verrucosus
Red listing status: Least Concern

Photo by McCleland Warren, 2009. URL: FrogMAP: 1632

Distribution

B. verrucosus is endemic to the atlas region. It occurs along the Great Escarpment, from the Nico Malan Pass (3226DA) in Eastern Cape Province, northward through Lesotho, KwaZulu-Natal and Swaziland, to the Blyde River Canyon Nature Reserve (2430DB) in Mpumalanga. A single specimen was collected on the border of Lesotho, in eastern Free State (Bates 1995). The species descends into moist grassland and forest east of the escarpment, reaching the coast at Coffee Bay (3129CD), and extending along the coast as far north as Empangeni (2831DD). The most southerly record is based on a museum specimen from Zuurberg (3325BC).

The great variation in colour and markings present in different populations of this species is attributed to crypsis. For example, individuals living in forest and along the forest fringe at Graskop (2430DD) are black with fine, cream speckles, while those living on light sandy soils at Eshowe are uniformly light brown (Minter 1998). Populations from grassland habitats in Eastern Cape Province exhibit a varying degree of light brown mottling on a dark brown background, and were previously referred to a separate subspecies, B. v. tympanifer. However, similar marking are seen on specimens from grassland habitats in KwaZulu-Natal and Mpumalanga, while a population sampled at the grassland/forest interface at Wesa (3029DA) contains entirely melanistic as well as mottled individuals (Lambiris 1989a; Minter 1998). Therefore, B. v. tympanifer does not represent a valid subspecies, but rather a cryptic colour variation in grassland (Minter 1998). These various populations show no differences in advertisement-call structure, which confirms that they are conspecific (Minter 1998).

Breviceps maculatus, described from montane grassland in the KwaZulu-Natal Drakensberg (FitzSimons 1947), has been recognized by some authors as a distinct species (Poynton 1964; Lambiris 1989a, 1991) on the basis of dorsal markings and larynx structure, while others have placed maculatus in the synonymy of B. verrucosus because of the similarity of their advertisement calls (Passmore and Carruthers 1979, 1995; Bates 1995; A. Channing pers. comm.; pers. obs.). B. maculatus is not treated as a separate taxon in this atlas, but an analysis of a larger sample of specimens and calls is required in order to validate this viewpoint.

The atlas data are reliable, but incomplete. The taxonomic status and distribution of populations in Lesotho, and along the escarpment in Mpumalanga, and possibly Limpopo Province, warrant further investigation (see B. sylvestris species account).

Habitat

Along the great escarpment, this species occurs in Moist Upland Grassland, North-eastern Mountain Grassland, Afro Mountain Grassland and adjacent Afromontane Forest. Along the Eastern Cape and KwaZulu-Natal coast it inhabits Coastal Bushveld-Grassland, Coastal Forest, Sand Forest, and Dune Thicket; at Pennington (3030BC) males were heard calling in dense, matted grass, five metres from the high-water mark (Minter 1998). Between the coast and the escarpment in KwaZulu-Natal, it is found in Short Mistbelt Grassland. At Eshowe, calling males were collected in suburban gardens (Minter 1998).

Factors that are common to these vegetation types, and may limit the distribution of this species, are annual rainfall in excess of 700 mm and well-shaded soil, which result in higher soil moisture levels over relatively longer periods than is the case in drier, more open habitats.

Life history

During dry periods, B. verrucosus remains below the surface. Minter (1998) followed a shallow burrow for 3 m until it dipped down and disappeared under a large rock, and found deep, vertical burrows near the call sites of several males. Specimens have also been collected under rocks (Jacobsen 1989).

The breeding period is relatively short, commencing with the first spring rains in late August to early September and seldom extending beyond mid-November. Choruses develop rapidly in rain, drizzle or heavy mist and continue unabated, day and night, as long as the wet weather lasts. Males are prompted to vocalize by the calls of their immediate neighbours, and in this way bouts of calling spread through the population in waves, as in B. adspersus. B. verrucosus is easily prompted to call by a tape recording or human imitation of the call, even when no other calling is taking place (pers. obs.). Calling is inhibited by wind and low temperatures (Minter 1998).

The call site is usually a well-concealed, shallow depression under dense, matted grass or leaf litter, but males may call at the surface, or from elevated positions on grass tussocks, up to 40 cm from the ground (Poynton and Pritchard 1976; Minter 1998). Amplexus, oviposition and development have not been recorded.

Food items include amphipods, isopods, juvenile myriapods, caterpillars, beetles and ants (Poynton and Pritchard 1976).

Conservation

B. verrucosus is widely distributed in a variety of habitats and does not appear to be at risk. It occurs in a number of provincial nature reserves and in the Golden Gate Highlands National Park (Bates 1995).

Current distribution map

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