With no other clues than the label of an Afzelius crab specimen with just two words “Sierra Leone”, a team of researchers found this super-rare freshwater crab 225 years later.
Finding rare and near-extinct species has never been easy.
In January 2021, Pierre A Mvogo Ndongo traveled to Sierra Leone to find an almost forgotten land-dwelling super-rare crab. One of them is the Afzelius crab (Afrithelphusa afzelii), last seen in 1796.
Super rare crab species
Mvogo Ndongo’s expedition was primarily in search of a rainbow-colored, terrestrial Sierra Leone crab named Afrithelphusa leonensis. This is a species of crab that has been missing for 65 years and is thought to be extinct.
His other hope is to find the Afzelius crab (Afrithelphusa afzelii).
Both crab species are terrestrial, living in burrows in the rainforest floor. “Most freshwater crabs in Africa live in rivers, streams and lakes,” said Mvogo Ndongo, a lecturer at the Institute of Fisheries and Fisheries Science at Douala University in Cameroon.
“This rare species of crab belongs to a unique family of Afrotropicals that can breathe air, helping them to adapt to harsh habitats in the rainforest and often far from water sources. They are very colorful compared to other land crabs, can climb trees, live in crevices of rocks, burrow in swamps or in the forest floor,” he analyzed.
He said Sierra Leone, Guinea and Liberia are the only three countries in Africa with this crab species and only five are known.
Within three weeks of working with local communities in the northern, southern and southeastern provinces of Sierra Leone, Mvogo Ndongo found no clues and felt hopeless.
Usually, scientific discoveries are made based on the previous clues of their predecessors. But with this case, Mvogo Ndongo has nothing in hand.
“For the past 225 years, no one has seen Afrithelphusa afzelii, the only information about them is a specimen label called ‘Sierra Leone’ – a rather obscure location indeed. We deduced that it was collected. collected within walking distance of Freetown, so we started surveying in the woods in that vicinity. Still, it was all too vague,” he said.
Live very deep in the caveThe team asked local people if they had seen any crabs living on land far from rivers and streams. Finally, a man took them to his farm at the edge of the woods, and they found them.
The day after finding the Afzelius crab, Mvogo Ndongo went to the Sugar Loaf Mountain forest, south of Freetown. With limited time due to the upcoming blockade of the Covid-19 epidemic, he went around Lake Guma in search.
It was not until he went deep into the forest that he found that rare crab. They live in burrows so deep that Mvogo Ndongo’s team has to carefully dig them up with picks and machetes, before cleaning the dirt off of them, revealing colorful shells. These are considered to be the first living specimens seen since 1955.
Along with the rediscovered Sierra Leone and Afzelius crabs, they also found two new freshwater crab species. However, the crab’s habitat is threatened by deforestation for farming and firewood.
“We are happy to have discovered species that were thought to have been lost, sad that they are on the verge of extinction and urgently need urgent intervention to protect them in the long term,” said Neil Cumberlidge, professor of Science. Biologist at Northern Michigan University, who teamed up with Mvogo Ndongo on the expedition, said.
Once the crabs are known, scientists hope they will be protected.
“The new data allow us to reassess the redlisting status of each species in this group, which could potentially be classified as ‘critically endangered’, which is near-extinct,” Cumberlidge said. speak.
“The next step we will take is an action plan for them and implementation of protective measures in the field with Sierra Leone conservationists to save these crabs from extinction,” he said.