Afrithelphusa is a genus of freshwater crabs in the family Deckeniidae. It contains four species, all of which were formerly listed as critically endangered by the International Union for Conservation of Nature (IUCN). They are all endemic to the Upper Guinean forests of Guinea and Sierra Leone.
Ceylonthelphusa is a genus of freshwater crabs endemic to Sri Lanka, where they live in moist lowland forests, swamps and rivers. Many of the species are on the IUCN Red List of threatened species, with the greatest risk factor being habitat loss. Ceylonthelphusa contains these species:
Louisea is a genus of freshwater crab in the family Potamonautidae, containing two species, Louisea balssi and Louisea edeaensis. Both species are endemic to Cameroon and listed as endangered species on the IUCN Red List.
Mahatha is a genus of freshwater crabs endemic to Sri Lanka. Four of the six species are critically endangered due to habitat loss, and two are listed as Least Concern on the IUCN Red List.
Oziotelphusa is a genus of freshwater crabs in the family Gecarcinucidae. Its members are found in Sri Lanka and southern India. The genus was formerly placed within family Parathelphusidae, but now it is accepted that Parathelphusidae is the junior synonym of Gecarcinucidae.
Perbrinckia is a genus of freshwater crabs of the family Gecarcinucidae that is endemic to Sri Lanka, named after Per Brinck. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, and rivers. It contains 14 species, most of which are included on the IUCN Red List as critically endangered species (CR) or vulnerable species (VU) because they are threatened by habitat loss; only one species is of least concern (LC).
Platythelphusa is a genus of freshwater crabs endemic to Lake Tanganyika. It has been placed in a number of families, including a monotypic family, Platythelphusidae, as well as Potamidae and its current position in the Potamonautidae, and has also been treated as a subgenus of Potamonautes. It forms a monophyletic group, possibly nested within the genus Potamonautes, which would therefore be paraphyletic. The genus is the only evolutionary radiation of crabs to have occurred in a freshwater lake, and it occurred recently, probably since the Pliocene. This parallels the better known radiation of cichlid fishes in Lake Tanganyika. Only one other species of freshwater crab is found in Lake Tanganyika, Potamonautes platynotus.
Rotundopotamonautes berardi is a species of freshwater crab in the family Potamonautidae. It is found in the Nile Basin in Egypt, Ethiopia, Sudan, Tanzania and Uganda. Its natural habitats are rivers and streams.
Potamonautes gerdalensis is a species of crab in the family Potamonautidae. It is found in the Democratic Republic of the Congo, Kenya, Tanzania, and Uganda. Its natural habitats are rivers and freshwater lakes. It is threatened by habitat loss.
Potamonautes johnstoni is a species of freshwater crab in the family Potamonautidae. It is found in rivers in Kenya and Tanzania, with unconfirmed records from Malawi and the Democratic Republic of the Congo. The species' distribution includes Kilimanjaro, Nekona, Mrogoro and the Usambara Mountains.
Potamonautes lirrangensis, the Malawi blue crab, is a species of freshwater crab in the family Potamonautidae. This common and widespread species is found in Lake Malawi, Lake Kivu, the upper Congo River Basin and Malagarasi River in the Democratic Republic of the Congo, Malawi, Rwanda, and Tanzania. In the freshwater aquarium trade it is sometimes sold under the synonym Potamonautes orbitospinus.
Potamonautes niloticus is a species of freshwater crab in the family Potamonautidae. It is found in the Nile Basin in Egypt, Ethiopia, Rwanda, Sudan, and Uganda. Numerous specimens of P. niloticus are known from Miocene deposits around Lake Albert.
Arcopotamonautes platycentron is a species of freshwater crab in the family Potamonautidae, which is endemic to Lake Chala in Kenya and Tanzania. It was originally described by Franz Martin Hilgendorf in 1897, as Telphusa platycentron.
Spiralothelphusa is a genus of freshwater crabs in the family Gecarcinucidae. It contains these species, all of which are included on the IUCN Red List:
Deckenia is a genus of freshwater crabs from East Africa, in the family Potamonautidae, or sometimes in a family of its own, Deckeniidae. The genus was named by Hilgendorf after Karl Klaus von der Decken who collected the first examples during his expeditions to Africa. Both species live in swamps from Eyl in Somalia to Dar es Salaam, Tanzania, both in coastal areas and further inland. A third species, Deckenia alluaudi, lives in the Seychelles, and has been transferred to a separate genus, Seychellum.
Johora singaporensis, the Singapore stream crab or Singapore freshwater crab, is a critically endangered species of freshwater crab endemic to Singapore. It grows to a size of 30 millimetres (1.2 in) wide.
Disparithelphusa pecki is a species of freshwater crab in the family Pseudothelphusidae, and the only species in the genus Disparithelphusa.
Brasiliothelphusa tapajoensis is a species of freshwater crabs in the family Pseudothelphusidae, and the only species in the genus Brasiliothelphusa. It was described in 1986 from specimens caught in the Rio Tapajós in the state of Pará, Brazil. It is listed as Data Deficient on the IUCN Red List.
Around 1,300 species of freshwater crabs are distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs, which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas. As a result, a large proportion are threatened with extinction.
The Sri Lanka tree crab,, is a species of freshwater crabs of the family Gecarcinucidae that is endemic to Sri Lanka. It is the only known tree climbing freshwater crab found in the country. The crab is discovered from 11 localities from Sri Lanka throughout Kalu River, Walawe River and Gin River basins. Adult are known to survive well in rainwater-filled tree hollows of trees such as Shorea sp., Artocarpus sp., Dillenia sp., Garcinia sp., Myristica sp., and Gyrinops walla. Females with youngs can be seen during February and March on the ground, never within tree hollows. The known predators are Greater coucal, White-throated kingfisher, Sri Lanka grey hornbill and Eurasian otter.
