John Gould described the Australasian darter as "Plotus novaehollandiae" in 1847. Closely related to American ("Anhinga anhinga"), African ("Anhinga rufa"), and Oriental ("Anhinga melanogaster") darters, the Australasian darter has been classed as a subspecies of the African or African plus Oriental darters. All four have also been classed as a single species. Examination of the leg bones indicates the three Old World species are more closely related to each other with the American species more divergent. Genetic analysis showed it differed from "A. rufa" to a degree equivalent to that between other separate species, and shifted consensus to treating the Australasian darter as a separate species.