Common names: Rose’s ghost frog, thumbed ghost frog, Tafelbergse spookpadda (Afr.)
Derivation of scientific name
The name name ‘Heleophryne’ comes from the Greek words ‘hélos’ meaning ‘marsh’ and ‘phrynes’ meaning toad. However, this name is inappropriate because members of the family neither live in marshes nor are they toads. The species is named after the famous herpetologist and naturalist, Walter Rose (1884–1964). The common name, ‘ghost frog’ originates from where the genus was first recorded, namely Skeleton Gorge on the eastern slopes of Table Mountain, which is a treacherous, steep and ghostly ravine. The entire genus is endemic to South Africa, Lesotho and Swaziland.
Introduction
The Table Mountain ghost frog is a rare and elusive frog species that is endemic to Table Mountain in the Western Cape. It has a very small natural range of 7–8 km2 that is restricted to perennial mountain streams on the eastern and southern slopes of the mountain. It is morphologically well adapted to live in fast flowing mountain streams; adults have webbed toes that have sucker-like disc pads at the tips that help frogs cling on to slippery and wet rock surfaces, while tadpoles have sucker-like mouthparts that are also used to gain purchase on wet surfaces and to scrap algae from rocks when feeding. It is listed as Critically Endangered by the IUCN Red List because of its small and restricted natural range (less than 9 km2) and perceived threats from habitat modification.
How to recognise a Table Mountain ghost frog
The Table Mountain ghost frog is approximately 5–6 cm from snout to vent with a squat, depressed body that allows it to enter small moist rock cracks, and toes that allow it to grip smooth surfaces. Adults are green in colour, with mottled purple or reddish-brown patches. They have a rudimentary thumb structure and large eyes with vertical pupils. The hind legs are fully webbed and the tips of the toes and fingers have sucker-like disc pads. Females (60 mm in length) are slightly larger than the males (50 mm).
Getting around
Tadpoles have sucker-like mouthparts that are used for clinging on to rocks in fast flowing streams and they also have strong muscular tails to assist in swimming. The hind legs of adults are fully webbed and assist in swimming but they are poor jumpers. After metamorphosis, individuals leave the stream before the winter rains and move to large damp rocks, rock faces covered in moss and rock cracks found close to the streams. The species seems to be quite mobile on land because adults have been found well away from streams. The species is also known to visit and stay in caves for parts of its life cycle.
Communicating
Male mating calls have been recorded in December and consist of a brief click, about 30 milliseconds long, with an emphasised rate of 1.8 kHz.
Distribution
The Table Mountain ghost frog is endemic to Table Mountain in the Western Cape. It has a very small and natural range of 7–8 km2 that is restricted to perennial mountain streams on the eastern, southern and marginal western slopes of the mountain.
Habitat
The species inhabits rocky, fast-flowing, perennial mountain streams (flow throughout the year) in forest and Fynbos vegetation types. The perennial nature of the rivers is needed to facilitate the year-long development of the tadpoles.
Food
Table Mountain ghost frog adults are hard to find and occur in very low numbers; therefore not much is known about their habits or life history. Tadpoles have large sucker-like mouthparts that are used to feed on algae on rock surfaces and it is thought that adults feed on insects.
Sex and Life cycles
There is limited information available on the breeding habits of the Table Mountain ghost frog. Breeding occurs in spring and summer during low stream flow. During the breeding season, males develop folds of loose skin that increase their oxygen uptake in the water, and both sexes develop spiny structures on their bodies that allow for better contact during amplexus (the mating embrace). Females bearing eggs have been collected in October–December. Tadpoles develop slowly in cold mountain streams and the larval stage lasts at least two breeding seasons.
THE BIG PICTURE
Smart Strategies
Tadpoles have sucker-like mouthparts that are not only used for algal feeding, but also for securing a firm grip on rocks in fast flowing streams. The rest of the body is streamlined so that the water flows over them with minimal resistance. Adults have webbed toes that have sucker-like disc pads at the tips that help the frogs to cling on to slippery and wet rock surfaces.
Poorer world without me
The risk of extinction for the Table Mountain ghost frog is high because of its small population size and restricted range. It is therefore important to protect and conserve the remaining wild populations and the habitats in which they occur.
Conservation status and what the future holds
The Table Mountain ghost frog is listed as Critically Endangered by the IUCN Red List because of its small and restricted natural range (less than 9 km2) and perceived threats from habitat modification. These threats include habitat loss through construction of dams upstream of prime habitat, excessive water abstraction, erosion, alien vegetation and the high volumes of visitor traffic into the park. Approximately 20% of the habitat has been lost over the past 30 years. Even though the entire available habitat is within protected areas, its survival is not guaranteed. Ongoing projects are monitoring tadpole population trends and habitat threats.
Relatives
The family Heleophrynidae, commonly known as ghost frogs, consists of seven species from two genera, Heleophryne and Hadromophryne, which are endemic to mountain streams in South Africa, Lesotho and Swaziland. The Natal ghost frog, Hadromophryne natalensis, is the only species in the genus Hadromophryne and occurs in KwaZulu-Natal, Lesotho and Swaziland. The other genus Heleophryne comprises of six species that occur in mountain ranges in Northern, Western and Eastern Cape.
These include the Cederberg ghost frog, H. depressa (Cederberg range, Western Cape); Hewitt’s ghost frog, H. hewitti (Elandsberg Range, Eastern Cape); eastern ghost frog, H. orientalis (Langeberg Mountains to Gouritz River valley, Eastern Cape); Purcell’s ghost frog, H. purcelli (Cederberg range, Western Cape), royal ghost frog, H. regis (eastern part of the Cape Fold Mountains, east of the Gouritz River valley to the Huis River) and the Table Mountain or Rose’s ghost frog, H. rosei (Table Mountain, Western Cape).
Scientific classification
Name: Heleophryne rosei Hewitt, 1925
Class: Amphibia
Order: Anura
Family: Heleophrynidae
Genus: Heleophryne
Species: H. rosei
References and further reading
- Amphibia Web (February, 2010) http://amphibiaweb.org/cgi-bin/amphib_query?query_src=aw_lists_alpha_&where-genus=Heleophryne&where-species=rosei.
- Blaustein A.R. & Dobson, A. 2006. Extinctions: a message from the frogs. Nature 439: 143, 144.
- Boycott, R.C. 1982. On the taxonomic status of Heleophryne regis Hewitt, 1909 (Anura: Leptodactylidae). Ann. Cape Provincial. Museums 14: 89–107.
- Boycott, R.C. 1988. Description of a new species of Heleophryne Sclater, 1899 from the Cape Province, South Africa (Anura: Heleophrynidae). Ann. Cape Provincial Museums 16: 309–319.
- Boycott, R.C. 2004. Capensibufo tradouwi, in L.R. Minter, M. Burger, J.A. Harrison, H.H. Braack, P.J. Bishop & D. Kloepfer (Eds.), Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland: 90, 91. SI/MAB Series #9. Smithsonian Institution, Washington DC.
- Boycott, R.C. 2004. Heleophryne orientalis FitzSimons, (1946), in L.R. Minter, M. Burger, J.A. Harrison, H.H. Braack, P.J. Bishop & D. Kloepfer (Eds.), Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland: 102, 103. SI/MAB Series #9. Smithsonian Institution, Washington DC.
- Boycott, R.C. 2004. Heleophryne regis Hewitt, (1909), in L.R. Minter, M. Burger, J.A. Harrison, H.H. Braack, P.J. Bishop & D. Kloepfer (Eds.), Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland: 106, 107. SI/MAB Series #9. Smithsonian Institution, Washington DC.
- Du Preez, L.H. & Carruthers, V.C. 2009. A complete guide to the frogs of southern Africa. Struik, Cape Town.
- De Villiers, A.L. 2004. Heleophryne rosei Hewitt, 1925 in L.R. Minter, M. Burger, J.A. Harrison, H.H. Braack, P.J. Bishop & D. Kloepfer (Eds.), Atlas and Red Data Book of the Frogs of South Africa, Lesotho and Swaziland: 108–111. SI/MAB Series #9. Smithsonian Institution, Washington, DC.
- Evolutionarily Distinct and Globally Endangered (EDGE) (February, 2010) http://www.edgeofexistence.org/amphibians/species_info.php?id=561.
- Gibbons, J.W., Scott, D.E., Ryan, T.J., Buhlmann, K.A., Tuberville, T.D., Metts, B.S. , Greene, J.L., Mills, T., Leiden, Y., Poppy, S. & Winne, C.T. 2000. The global decline of reptiles, Déjà vu Amphibians. BioScience 50: 653–666.
- IUCN Red List (February, 2010). http://www.iucnredlist.org/.
- World Heritage Centre, UNESCO (February, 2010). http://whc.unesco.org/.
Author: Elton le Roux
South African National Biodiversity Institute/GKBC/EE
August 2014