Updated 24/03/2020

Cape Town – A recent molecular genetic study has revealed hidden cryptic species within a known forest gecko from the east coast of South Africa – the Pondo flat gecko.

Stellenbosch University MSc student Theo Busschau’s findings suggest that the Pondo flat gecko (Afroedura pondolia) is a ‘species complex’ comprising at least four cryptic lineages classified under the existing A. pondolia name.

A species complex is a group of closely related organisms that are very similar to the point that the boundaries between them are often unclear.

“The species complex started diversifying during the Late Miocene which suggests that forest fragmentation related to climatic shifts drove diversification in the group,” Busschau told the FBIP.

According to Busschau forest fragmentation since the Late Miocene may have driven diversification in other forest-living species in the region.

Therefore these forests possibly harbour higher levels of diversity than currently thought.

The study, published in the Molecular Phylogenetics and Evolution journal, formed part of the Eastern Cape Forests project – one of the Large Grant Projects funded by the Foundational Biodiversity Information Programme (FBIP).

Conservation implications

Busschau’s findings show that the individual cryptic lineages in the A. pondolia complex have much smaller ranges than the species name they are classified under.

In addition most of A. pondolia’s coastal forest habitat is threatened by increased urban development, making these species a high priority in terms of conservation.

“If other forest-living species show similar patterns to the Pondo flat gecko, as I expect, these findings highlight the importance of protecting forest habitats and maintaining forest corridors to conserve the high diversity in the east coast forests of South Africa,” he said.

Ecosystem importance

Geckos play an important role in maintaining ecological balance by keeping insect populations in check.

They are also food to many birds, mammals and other reptiles. As such geckos represent an important link in the food chain.

Busschau warns that the removal of geckos from an ecosystem may have a cascade of consequences both lower and higher up in the food chain.

“Sensitive species like Afroedura sp. are important bioindicators of biodiversity and ecosystem health, particularly in disturbed habitats where they are often displaced by the invasive tropical house geckos (Hemidactylus mabouia).

Future work

Busschau’s work has identified possible new species within the A. pondolia complex based largely on genetic data.

His morphological analyses identified some differences among the candidate species but in order for researchers to formally describe the species they will have to take a closer look for “fixed morphological differences”.

“My sample size available for the morphological analyses was limited – the next step is to increase the sample sizes in some localities and look at additional morphological characters for the species descriptions,” said Busschau.

READ MORE: Velvet worms ‘raise flag’ on SA’s threatened indigenous forests

Evidence for cryptic diversification in a rupicolous forest-dwelling gecko from a biodiversity hotspot by Dane McDonald on Scribd