Parathelphusa

Parathelphusa is a genus of freshwater crabs in the family Gecarcinucidae and subfamily Parathelphusinae, primarily distributed across Southeast Asia, including countries such as Indonesia, the Philippines, and Singapore. Southeast Asia has some of the highest diversity of freshwater crabs around the world. Some species in this genus are endemic to Singapore, such as the critically endangered Parathelphusa reticulata (swamp forest crab) which became more well-known after its feature on a series of crab stamps by the Singapore Philatelic Bureau in 1992.

This genus comprises over 49 recognised species, with notable diversity in morphology and habitat preferences. For example, the Parathelphusa reticulata gets up to 4cm in size and lives in the swamp forest habitat, while the Parathelphusa maculata gets up to 6cm in size and lives in streams and nature reserves. The Parathelphusa pantherina (panther crab) is known for its striking colouration, with a patterned carapace resembling a panther's spots.

Despite their ecological importance, many species of Parathelphusa face the threats of habitat destruction, pollution, and excessive harvesting. For instance, Parathelphusa reticulata is critically endangered due to habitat loss in Singapore's swamp forests. Conservation efforts, including ex-situ breeding programs, are vital to preserving these unique freshwater crabs and their ecosystems.