Aww, this little hopper just wants to hug you! My arms made that same exact motion when I saw the lack of information about it.

Only being found in the highlands of Cameroon doesn’t exactly help it, but it seems to be overshadowed – understandably – by its far more endangered cohort, the Lake Oku clawed frog. But come on, it’s got “volcano” in its name!

Its Latin moniker Xenopus amieti actually comes from Dr. J-L Amiet of the University of Yaoundé and so also carries the name “Amiet’s clawed frog”. While the good doctor wasn’t its discoverer, he did suggest it might be a separate species. Because wouldn’t you know it, as well as living in a remote area, it’s also very similar to and intermingled with other neighbouring frogs.

Frog fusion

Back in 1979, Kobel et al. captured a range of local frogs from the areas of Galim and dormant volcano Mount Manengouba, and initially considered them to be Fraser’s clawed frog (yes, the same Fraser who tried CPR on an umbrellabird).

However, on closer inspection, they found that they were chunkier, had shorter and slightly more colourful “subocular tentacles” (flaps under the eyes), darker bellies, and more “lateral line plaques” around their eyes.

That’s not a polite way of saying “wrinkles” – the “lateral line system”, found in amphibians and some fishes, is a network of sensory organs for detecting movement and pressure changes in water, so the volcano clawed frog seems to have more of these markers dotted about its face. That’s not the only thing it has in spades.

Web-toed wonder

With the exception of germ line cells (beyond the scope of this coffee-break reading), human body cells are diploids, meaning they contain two sets of chromosomes – one taken from each parent.

The volcano clawed frog, like many others in its genus, is what’s known as a tetraploid, carrying four sets of chromosomes. We’re not exactly sure why, but it’s possible its ancestor interbred with other frog species who were equally generous with their chromosomes.

According to conservation expert Thomas Doherty-Bone, it’s also linked to shaking off any pesky parasites that started off as symbiotic but later began to cramp its style. Its genus, Xenopus, harks back 20-23 million years, so there’s been plenty of time for it to hybridise to its heart’s content. The volcano clawed frog can be just as mysterious on the outside, too.

“Mysterious”, just one of many adjectives to describe this.

Some of its skin secretions, for instance, have left us scratching our heads. Among with some other toxins, they contain caerulein and xenopsin peptides, which can both help release insulin, and possibly induce gagging or vomiting if ingested. The jury’s still out, but these could help Type 2 diabetes research, and may be a way of protecting the frog from being eaten by predators. That being said, it’s still a popular local snack.

Is that lake stocked?

In the dry season in particular, the volcano clawed frog is a good source of protein, and since it sometimes makes its home in farm ponds and waterholes, it’s not hard to catch. Kobel et al. described local Mount Manengouba women dipping fern-filled wicker baskets into the water, immersing them for a few minutes, then lifting them out again complete with unfortunate catch. Even the tadpoles are eaten, but it would be nice to know more about the food before popping it down the hatch!

What I could extrapolate about the volcano clawed frog’s breeding habits – mostly from articles about other species – is that when a male is ready for romance, he lets loose a high-pitched call burst to attract any local ladies. If she isn’t in the mood, she responds with a slower, lower frequency noise with a shorter range, one which the male will also use if grabbed by a rival. Since most of the specimens gathered by Kobel et al. were post-tadpole juveniles, it’s thought that, sensibly, the volcano clawed frog breeds during the wet season.

Even for those sensible enough to hang around waterholes and swampland rather than farms – thus mostly avoiding the fun of pesticide run-off – they’re still at risk of habitat loss. Lush grassland is obviously ideal for livestock, and as farms and associated human settlements expand, there’s less and less water and habitat for the volcano clawed frog to splosh about in.

Will it have a resurgence one day, just like its namesake? That would be the only good kind of volcanic explosion, to be honest.

TLDR

Latin: Xenopus amieti

What? Chunky little grey frog with gold speckles, a dark belly, and long front digits.

Where? Western Cameroon, specifically the highland areas near Mount Manengouba, Bamileke and Bamenda, up to 2,396 metres / 7,860 feet altitude.

How big? About 4.8 cm / 1.8 inches long.

Endangered? Considered Vulnerable from habitat loss due to farming expansion, competition with cattle, and also pollution from pesticides. It’s a local source of food too, especially in the dry season.

Probable motto: No, I don’t have literal volcanoes for claws. What were you expecting?

They look…interesting. Do they need my help at all?

Yes in terms of habitat loss, but I couldn’t find any campaigns for it or its home. However, I did come across a captive breeding programme for the endangered Lake Oku clawed frog at the California Academy of Sciences, and the African Wildlife Foundation funds a range of projects in Cameroon overall.

Just to prove I’m not fibbing:

Blackburn, David C. et al. 2019. “The Earliest Fossil of the African Clawed Frog (Genus Xenopus) from Sub-Saharan Africa“, Journal of Herpetology 53(2):125-130.

Doherty-Bone, T.M. 2008. “Introducing the Lake Oku clawed frog“. Edge of Existence.

Doherty-Bone, T.M. et al. 2013. “Morbidity and mortality of the Critically Endangered Lake Oku clawed frog Xenopus longipes“, Endangered Species Research 21:115-118.

Fritts, Rachel. 2017. “Nearly half of Mount Oku frogs are in danger of croaking, study finds“. Mongabay.

Hall, Ian C. et al. 2016. “Sex differences and endocrine regulation of auditory‑evoked, neural responses in African clawed frogs (Xenopus)“, Journal of Comparative Physiology A, 202:17–34.

IUCN SSC Amphibian Specialist Group. 2018. “Xenopus amietiThe IUCN Red List of Threatened Species” 2018: e.T58168A16929588.

Kobel, H.R. et al. 1980. “Xenopus amieti sp. nov. (Anura: Pipidae) from the Cameroons, another case of tetraploidy“, Revue suisse de zoologie 87(4):912-916.

Notice of Amendment: Before the Fish, Wildlife and Parks Commission of the State of Montana“. 2010. Montana Administrative Register.

Tetraploid: definition and explanation“. No date. Study.com.

Xenopus amieti Kobel, du Pasquier, Fischberg, and Gloor, 1980″. No date. American Museum of Natural History.

Zahid, Osama et al. 2011. “Caerulein-and xenopsin-related peptides with insulin-releasing activities from skin secretions of the clawed frogs, Xenopus borealis and Xenopus amieti (Pipidae)“, General and Comparative Endocrinology 172(2):314-20.

Zug, George R. No date. “Lateral line system“. Britannica.com.

Featured image credit: “Volcano clawed frog in water”, © Lukas Blazek