Sierra Leone Crab

scientific name: Afrithelphusa leonensis

Last seen: 1955 in West Africa

Years lost: 64

The Sierra Leone Crab is restricted to freshwater habitats in the Upper Guinea rainforest zone and known only from three individuals collected in 1955. Relatives of these crabs were recently rediscovered and have striking orange and purple coloration, an unusual inflated carapace and an unusual ecology—they climb trees. A search for the Sierra Leone Crab could also include a search for two other lost species in the Upper Guinea rainforest zone, Afzeli’s Crab (Afrithelphusa azfelli), which is known from two individuals collected before 1800, and Gerhilda’s Crab (Afrithelphusa gerhildae). All three species are likely lost because they live in obscure, out-of-the-way niches such as trees, caves, mountain streams and cracks in rocks.