Family Brevicipitidae

Breviceps acutirostris Poynton, 1963

Strawberry Rain Frog, Cape Short-headed Frog, Aarbei-blaasoppadda (A)

By J.A. Harrison

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

Photo by Hardaker T. & , 2012. URL: FrogMAP: 520

Distribution

B. acutirostris is restricted to the southwestern ranges of the Cape fold mountains. The most westerly range in which it occurs is the Hottentotsholland Mountains (3318DD, 3418BB), the most easterly the Langeberg Mountains (3321CD); these ranges also represent the northern limits of the species. The map indicates a gap in distribution corresponding to the eastern Hottentotsholland and Riviersonderend mountains; this apparent absence requires confirmation. The species does not occur on the Cape Peninsula. The eastern extremities of its range overlap that of B. fuscus.

The atlas records are reliable, but sparse. Additional surveys may fill some of the gaps, especially in mountainous areas not adequately covered during the atlas project. The advertisement calls of B. acutirostris and B. fuscus are quite similar in structure (Passmore and Carruthers 1995; Channing 2001) although the call rate is distinctly faster in acutirostris (L.R. Minter pers. obs). In areas where both species may occur, aural records should have been supported by tape recordings of the calls, and by voucher specimens. This was seldom done, resulting in the possibility of some misidentifications.

Habitat

B. acutirostris occurs only in areas of high precipitation in uplands and mountains, both in Mountain Fynbos and in Afromontane Forest. Where mountains reach the coast, the species can occur at sea level (e.g. Betty’s Bay 3418BD; Grootbos 3419CB). The soils in these habitats are coarse, acidic sands derived from Table Mountain Sandstone, frequently admixed with peaty deposits.

Life history

Calling occurs both at night and during the day, usually during and after rain showers in winter and spring (June–November), but dense mist may be sufficient to stimulate calling. In Grootvadersbosch forest, males have been observed calling from above the ground, on top of logs (C.N. Spottiswoode pers. comm.; H. Braack pers. comm). In fynbos, the species has been found calling above ground in dense vegetation (M. Burger pers. comm), and from short burrows situated below low, covering vegetation (pers. obs.). Adhesive amplexus is employed during mating.

An amplexed pair, with a freshly laid egg mass comprising 24 eggs, was unearthed in Mountain Fynbos in the Boosmansbos Wilderness Area, on 22 October 1986 (D. McDonald pers. comm.). The pair was found in a chamber at the lower end of a network of tunnels covering an area of about 1 m². Some branches of the tunnels ended blindly while others formed loops off the main tunnel leading to the egg chamber. The nest site was located on a cool, moist slope in sandy loam soil, covered by prostrate Cliffortia ferruginea. The eggs measured 6.5–7.8 mm (mean = 7) in diameter (L.R. Minter unpubl. data).

Little is known about the biology of this species. Studies of the differences in call structure and habitat partitioning between B. acutirostris and B. fuscus, in areas of sympatry, would be of particular interest.

Conservation

The montane habitat of B. acutirostris is generally little disturbed and occurs within a number of protected areas such as the Marloth Nature Reserve, Boosmansbos Wilderness Area and Grootvadersbosch State Forest. This species is not threatened.

Current distribution map

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