Three new records of Padina in Japan based on morphological and molecular markers

Three species of the brown algal genus Padina (Dictyotales), Padina melemele I.A. Abbott et Magruder, Padina moffittiana I.A. Abbott et Huisman, and Padina thivyae Doty et Newhouse, which were originally described from Hawaii, are newly reported from some of the offshore islands of Southern Japan: P. melemele collected from Okinawa (Ryukyu Islands) and Chichi-jima (Ogasawara Islands), P. moffittiana from Okinawa I. and P. thivyae from Tanega-shima. Identifications are based on morphological comparisons with the original descriptions and herbarium specimens of these species identified by I. A. Abbott. Some minor differences included tetrasporangial sori that were formed only on one surface of the thallus in Japanese P. melemele and P. thivyae, whereas in the Hawaiian specimens they were sometimes formed on both surfaces. Japanese P. moffittiana had entire margins, whereas the Hawaiian specimens generally had fimbriate margins. Molecular analyses using rbcL and mitochondrial cox3 genes as molecular markers confirmed the identification of P. melemele and P. moffittiana. Unfortunately the record of P. thivyae could not be confirmed because we were unable to extract DNA from this species.