A new species of peacock spider, Maratus nemo sp. nov., is described from the vicinities of Mount McIntyre and Nangwarry, South Australia. Unusual among members of its genus, the new species appears to inhabit ephemeral wetland complexes on marshy vegetation in shallow water. The discovery of Maratus nemo sp. nov. is one of several recently described species attributed to the growing interest in amateur invertebrate macrophotography, with putative new species brought to attention of taxonomists through social media engagement.