Thiomargarita is a genus which includes the vacuolate sulfur bacteria species Thiomargarita namibiensis, Candidatus, Thiomargarita nelsonii, and Ca. Thiomargarita joergensenii. In 2022, scientists working in a Caribbean mangrove discovered an extremely large member of the genus, provisionally named Ca. T. magnifica, whose cells are easily visible to the naked eye at up to 2 centimetres (0.79 in) long.