Family Ptychadenidae

Ptychadena mascareniensis (Duméril and Bibron, 1841)

Mascarene Grass Frog, Mascarene Ridged Frog, Mascarenese Graspadda (A)

By L.R. Minter and N.I. Passmore

Currently accepted name: Ptychadena mascareniensis
Red listing status: Least Concern

Photo by Evans Nick, 2012. URL: FrogMAP: 609

Distribution

P. mascareniensis is widespread in savannas from Sierra Leone eastward through West Africa, and northward to Egypt. Its range extends southward to Angola, northern Namibia, northern Botswana and southern Mozambique. The species is also recorded from Madagascar, Seychelles and the Mascarene Islands, although it is possible that these populations represent a different taxon (Poynton 1964; Poynton and Broadley 1985b; Glaw and Vences 1994). In the atlas region, P. mascareniensis is uncommon and marginal in its distribution. It is recorded from the southeastern border of Mpumalanga to the coastal plain of northern KwaZulu-Natal, as far south as Shaka’s Kraal (2931AC).

Few records were collected during the atlas survey but the distribution range reflected in the map is regarded as reasonably accurate. The gaps within this range are probably the result of inadequate collecting rather than a real absence of the species.

Habitat

In Malawi, P. mascareniensis is recorded from swamps, marshes and pans in open, lowland savanna (Stewart 1967). In South Africa it seems to prefer permanent and semi-permanent pans and pools (Passmore 1978) but has also been recorded from brackish coastal pools (Lambiris 1989a). In the atlas region it inhabits Mixed Lowveld Bushveld, Sweet Lowveld Bushveld, Subhumid Lowveld Bushveld, and Coastal Lowveld Grassland, at altitudes up to 300 m. Annual rainfall in these habitats is 500–>1000 mm. During the day, adults conceal themselves in grass at the edges of pools, often sitting in shallow water (Stewart 1967).

Life history

Because these frogs occur at or near permanent bodies of water, they are probably active throughout the year. They feed on terrestrial beetles, bugs, spiders, earthworms and snails, as well as aquatic and semi-aquatic organisms such as tadpoles and froglets (Stewart 1967; Channing 2001). When disturbed, they leap into or away from the water, simultaneously expelling a jet of water from the bladder (Stewart 1967; Passmore and Carruthers 1995). When captured they adopt a rigid posture, and sometimes produce a foamy skin secretion and emit a moaning sound (Channing 2001).

Breeding takes place in the wet season from spring to autumn (Stewart 1967). Males call from concealed positions at the edges of shallow pans or pools in open grassy wetlands or open woodland marshes, and have also been observed calling from roadside ditches and a quarry (Jacobsen 1989; Lambiris 1989a; Passmore and Carruthers 1995). In addition to the advertisement call, several other call types are produced in different social contexts (Passmore 1978).

Aside from the record of small black and white eggs laid in shallow water at the edge of Lake Chilwa (Channing 2001), there appears to be no further information on the eggs or tadpoles of this species.

Conservation

Although P. mascareniensis is widely distributed in Africa, it has a marginal distribution in the atlas region and, from a national perspective, may warrant conservation action. A survey is necessary to locate breeding populations possibly missed during the atlas project. At present, not enough information is available to comment on the conservation status of this species within the atlas region.

Current distribution map

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