Exploring the hidden world of fynbos frogs

A recent grant from the Herpetological Association of Africa enabled the investigation of the taxonomically confusing species of Ghost Frogs.

Ghost Frogs (Family Heleophrynidae) are an endemic family of frogs that diverged from all other frogs 100 million years ago. These specialised frogs typically inhabit fast-flowing headwater habitats, with both adults and tadpoles having special adaptations for these extreme flow environments, where the rushing water would wash most frogs and tadpoles downstream. The adults have flattened bodies enabling them to fit into rock crevices, long limbs with expanded toe tips for gripping slippery surfaces and cryptic dorsal colouration for camouflage. The tadpoles are streamlined with a large, sucker-like oral disc, allowing them to cling to surfaces in fast-flowing water and even climb wet, vertical rocks.

Six known species occur in the Cape Ecoregion, of which four are endemic to the Western Cape. Heleophrynidae is currently the most threatened family of frogs in southern Africa, with nearly a third of all species threatened. The Table Mountain Ghost frog is listed as Critically Endangered. Taxonomically, some species in the genus are problematic, and the status of populations in the Outeniqua, Kammanassie, Kouga, and Baviaanskloof mountains remains uncertain, as does the exact relationship between the family Heleophrynidae and all other frogs.

To answer these evolutionary and conservation-relevant questions, DNA was collected at representative localities across the distribution range of the genus in the Western Cape. These samples, along with existing DNA from earlier collections, will be used for whole-genome sequencing. This data will be used to fully reveal and resolve the differences and similarities across the genus, to work out where the species boundaries exist, which is essential for conservation assessments and, in turn, informs conservation priorities and actions.