Searching for cryptic frogs is never easy. Preparations include consulting every amphibian guide book in one’s library, listening to the call on CD, and packing your water boots…
Then, once one has managed to access the correct habitat, the key is to isolate the target species call and slowly narrow down its location.
But the Rose’s Mountain Toadlet, Capensibufo rosei, throws another challenge in the intrepid naturalist’s path.
When one pages through the excellent ‘A Complete Guide to the Frogs of Southern Africa' by Louis du Preez and Vincent Carruthers, it is fantastic to listen to the accompanying CD and match the track number to the specific species page. One may be forgiven for thinking that the publisher has made a massive mistake by omitting the track number from the Rose’s Mountain Toadlet species page. But, this species is the only voiceless frog species in the entire southern Africa. The frog's tympanum and middle ear elements are completely lacking. Add this to the fact that the species is restricted to undisturbed montane fynbos, and usually confined to high mountain areas, and you have a very challenging species to find.
One of the tricks for searching for these frogs is to do so during their peak breeding season. As they do not call they will congregate at the same breeding pools during early spring, and if one knows what to look for then it becomes easier to track down individuals.
This was the trick I utilised to finding my first Capensibufo rosei.
We searched seeps and wetlands in the highest reaches of the Maanschynkop Nature Reserve, in the Kleinrivier Mountains, on the outskirts of Hermanus in the Western Cape and discovered a pool that was being utilized by the toadlets. The characteristic and interesting ‘string of pearls’ eggs already laid.
A search of the surrounding vegetation uncovered Capensibufo rosei but identifying the adult was not easy. Colour systems with amphibians can be incredibly variable and these tiny frogs were incredibly dark to match the deep black peat soils that they were located in. The expected bright red parotid glands were not prominent at all. It was only once artificial light was applied that we noticed these distinguishing features and knew for certain that we had a C. rosei in hand. This was very exciting for me, as this was a ‘lifer’ species, and I had the added bonus of seeing the incredible egg strings as well, so I was very happy.
But, I was not completely satisfied, and it kept bothering me that I have not yet seen a typically coloured Toadlet. I have often thought of making a detour to Cape Town to search for the Capensibufo on the peninsula in order to see this more typically red parotid gland colouration, but never did so.
Well, under the strangest of circumstances, I finally managed to see some specimens with this sought after colouration.
We were scratching around recently on top of the Soetmuisberg in the Napier Mountain Conservancy with good friends Cliff and Suretha Dorse.
Cliff and Suretha are phenomenal naturalists and the only thing more inspiring than their knowledge is their easy-going nature, enthusiasm and passion for biodiversity. Check out their website to see some of the incredible species they have managed to photograph during their travels and #EcoExplorations.
Suretha exclaimed that she had found a Capensibufo rosei!!!! What made this shocking was not the fact that Suretha had found the frog (she is a real expert at locating toadlets), but the fact that she had found one on top of the Napier mountains in the Overberg. While Napier does fall within the broader distribution range of the species, it has never been documented on any of the mountains of the central Overberg. The species is only known from six populations, with none of these in the vicinity of Napier. The species is known from the Cape Peninsula, Kogelberg, Hottentots Holland, Riviersonderend and the Kleinrivier mountains.
So, it was quite a find to discover this species in an entirely new location. We spent some time searching the surrounding area and managed to find another five individuals! Not only a new species for the Napier Mountain Conservancy, but a new breeding population and locality for the Rose’s Mountain Toadlet. The species has a conservation listing of vulnerable, so every little bit counts towards their conservation.
Taxonomic revisions for the species are currently underway and it is expected that the Cape Peninsula population will be split from the rest of the range. So, even though I have now feasted my eyes on the bright red of a Rose’s Mountain Toadlet's parotid gland, I may well still have to put Suretha’s skills to the test on the peninsula in the not too distant future!
Anyone interested in reading and learning more about this little Toadlet can visit the Animal Demography Units ‘FrogMAP’. This is an online Atlas of southern African Frogs and we urge everyone who has the passion and time to upload their sightings of any frog species onto the ‘FrogMAP’ to assist with future conservation action.