Family Heleophrynidae

Heleophryne orientalis FitzSimons, 1946

Eastern Ghost Frog, Oostelike Spookpadda (A)

By R.C. Boycott

Currently accepted name: Heleophryne orientalis
Red listing status: Least Concern

Photo by Hardaker T. & , 2012. URL: FrogMAP: 518

Distribution

This species is endemic to the Western Cape Province of South Africa. It occurs along the eastern Langeberg Mountains, from the vicinity of Montagu and Kogman’s Kloof (3320CC), eastward through Swellendam and Grootvadersbosch Forest Reserve (3320DD), probably as far east as the Gouritz River (3321DC). Recorded altitudinal range is 215–500 m (Boycott 1982; Visser 1990; Channing 2001).

The atlas records are reliable but incomplete. Heleophryne records allocated to H. orientalis (as presently defined) were based on the range of H. purcelli orientalis as recognized by Poynton (1964) and Boycott (1982). What remains to be determined are the eastern limits of the range of H. purcelli and the western limits of the range of H. orientalis. It is unlikely that the distributions of the two species overlap.

Habitat

This species inhabits clear, slow- to swift-flowing perennial mountain streams in forested ravines and gorges, in areas where the annual rainfall is 600–3000 mm (Boycott 1982). It is confined to patches of Afromontane Forest surrounded by Mesic Mountain Fynbos (Moll et al. 1984), as is the case with H. regis. The water in the streams is amber to dark brown owing to the presence of humic compounds.

Adults conceal themselves below stones along the edges of streams, and under submerged rocks in the streams. They have also been found near waterfalls and cascades, on wet rock faces, in rock cracks and in caves. The tadpoles may be found beneath submerged and partly submerged rocks in swift- and slow-flowing streams and in rocky pools. At some localities, such as Grootvadersbosch, streams that have a gradual incline may be reduced to shallow trickles in the dry season.

Life history

In March, three adult female specimens were collected from damp and dry horizontal rock cracks adjacent to the Dwars River in the eastern Langeberg Mountains. On dissection it was discovered that eggs, much reduced in size, were present in the reproductive tract of two of the females, while in the third, no eggs were present. These specimens also exhibited a reduction in the tiny asperities scattered over the dorsal surfaces of the forearms and head. These observations indicate the transition to a non-breeding condition at this time of the year.

H. orientalis breeds in early summer when river and stream flow is reduced. Visser (1990) recorded breeding from the fourth week of October to the end of November, and regarded this species as having the shortest breeding period of all Helophryne species. However, while this might be the peak breeding period, there are records of earlier and later breeding activity in Hermitage Kloof, just west of Swellendam, from mid-October to mid-December. Calling takes place during the day and at night, even up to 02:00.

Males call from beneath stones alongside and in streams, from exposed positions such as lichen-covered boulders near waterfalls and cascades, and in caves. Unlike most of the other Heleophryne species, the males of H. orientalis appear to form breeding aggregations, at least during peak periods. On several occasions, for example, two to three calling males were recorded under the same rock at Hermitage Kloof, west of Swellendam. At the same locality, several individuals were heard calling close together in a cave through which a shallow stream flowed. At Tradouw Pass, the distance separating six males, calling from exposed rock surfaces on the sides of a stream, was 0.2–3.5 m (L.R. Minter pers. obs.). Similar behaviour has been recorded in H. regis.

Oviposition in H. orientalis is virtually extra-aquatic, as the only available moisture is a thin layer of water seeping over the substrate on which the eggs are laid. This differs from the egg-laying habits of the other species such as H. purcelli, H. regis and H. hewitti which lay their eggs completely submerged in water. Clutches of 114–191 eggs, are laid under and between moss-covered boulders, or under small rocks in the streambed. Some egg clutches have been found under rocks that are partly on the river bank and partly in the river (Visser 1971, 1990).

Tadpoles feed on algae growing on submerged rock surfaces in streams and pools, and they take refuge under loose pebbles and boulders when disturbed. Their colour closely matches that of the water and the substrate on which they feed.

Conservation

H. orientalis occurs abundantly in forested ravines and gorges on the southern slopes of the eastern Langeberg Mountains and is under no threat. The species occurs in several private and public protected areas.

Current distribution map

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