Four newly recorded species of the calcified marine brown macroalgal genus Padina (Dictyotales, Phaeophyceae) for Australia.

Molecular phylogenetic analyses based on plastid-encoded rbcL and mitochondrial cox3 gene sequences, in combination with morphological observations, revealed the existence of the following four bistratose Padina species previously unreported from Australian coasts: Padina calcarea Ni-Ni-Win, S.G.A. Draisma, W.F. Prudhomme van Reine & H. Kawai, characterised by its bright yelloworange inferior thallus surface and chalky white, heavily calcified superior surface, and the presence of hairlines only on the inferior surface; P. macrophylla Ni-Ni-Win, M. Uchimura & H. Kawai, characterised by a moderately calcified thallus with broad, depressed hairlines on the inferior surface and narrow, not depressed hairlines on the superior surface, those hairlines that are largely spaced on each surface; P. moffittiana I.A. Abbott & Huisman, characterised by lightly calcified thalli with narrow, slightly depressed hairlines that are distributed in alternate sequence between the two surfaces at unequal distances, and broad reproductive sori in one or two rows in the fertile zone; and P. okinawaensis Ni-Ni-Win, S. Arai, M. Uchimura & H. Kawai, characterised by heavily calcified thalli, except at the hairlines, which form an alternation of uncalcified furrows and calcified glabrous zones on the inferior surface. With the addition of these four species, 13 Padina species are known from Australia. [ABSTRACT FROM AUTHOR]