Three new species of Asteromenia (Hymenocladiaceae, Rhodophyta) from Australia

Three new species of the red algal genus Asteromenia (Hymenocladiaceae, Rhodophyta) are described based on morphological and molecular analyses. DNA analyses of recent collections of topotype specimens of A. examinans from the Houtman Abrolhos Islands (Western Australia) have revealed that the specimens used in earlier studies were misidentified and represent an undescribed species, herein described as A. juliannae. Two additional new species, A. crenulata and A. praetermissa are described from the Cocos (Keeling) Islands, and Norfolk Island, respectively. For the most part, the new species showed morphological overlap and could not be discriminated based on morphology alone; DNA sequencing is therefore considered essential for accurate species recognition. The potential for misidentification of morphologically similar specimens highlights the need for sequence analyses and reference barcoding to be based on type or topotype specimens. The adoption of molecular methods in alpha taxonomy has led to the recognition of considerable diversity in the Rhodymeniales and it is envisaged that further collecting will add even more taxa to Australia's rich algal flora.