Dictyota korowai sp. nov. (Dictyotales, Phaeophyceae) from Manawatāwhi/Three Kings Islands, northern New Zealand, previously confused with Dictyota intermedia

A new species of Dictyota (Dictyotales, Phaeophyceae), formerly identified as D. intermedia, is described from Manawatāwhi/Three Kings Islands. Morphological and anatomical features, in addition to molecular sequence data, of specimens collected from Manawatāwhi and Rangitāhua/Kermadec Islands were compared and enabled us to confirm that D. intermedia is present at Rangitāhua and differs from specimens collected at Manawatāwhi. Dictyota korowai sp. nov. is endemic to Manawatāwhi and possesses distinctive morphological features including the development of tongue-like proliferations on both surfaces of the blades and a thickened midrib which extends from the base into the lower portion of the axes. The presence of D. sandvicensis on Rangitāhua is reported for the first time, a new record for the New Zealand macroalgal flora.