Scarlett's duck (Malacorhynchus scarletti) is an extinct duck species from New Zealand which was closely related to the Australian pink-eared duck (Malacorhynchus membranaceus). The scientific name commemorates the late New Zealand ornithologist and palaeontologist Ron Scarlett who discovered the holotype in 1941. However, previously undescribed bones of the species found in 1903 were rediscovered in the Otago Museum in 1998. At least 32 fossil remains from deposits in Pyramid Valley, at Ngapara in the South Island, and at Lake Poukawa in the North Island are in museum collections.