Siphonaria compressa, South Africa's most endangered marine mollusc

The plight of Siphonaria compressa, a critically endangered South African marine mollusc, is discussed. Present evidence suggests that although perhaps at one time more widely distributed, the species is now known only from Langebaan Lagoon, itself a habitat in a precarious position. Investigations into the reproductive cycle and population dynamics of the species and its tolerances to abiotic variables are highlighted as research priorities.