Characterization of Herposiphonia pectinata (Decaisne) comb. nov (Rhodomelaceae, Rhodophyta) from Western Australia, based on morphology and DNA barcoding

In Western Australia, six species of the red algal genus Herposiphonia are known from the low-intertidal to shallow subtidal zones in tropical to warm-temperate regions. Here, we transfer the poorly known Leveillea pectinata Decaisne to Herposiphonia based on a morphology and DNA barcoding of specimens collected from Cape Peron, south of Perth, Western Australia. Herposiphonia pectinata is characterized by a branching pattern of three determinate branches (d) between indeterminate laterals (i) (d/d/d/i), terete determinate branches arising from the same dorsal position (not deflected from side to side), 20-30 segments long with 11-13 pericentral cells per segment, and a lack of vegetative trichoblasts. Cystocarps are located medially on fertile branches and spermatangial branches with a sterile tip are secundly arranged. Morphological comparisons are made with Australian and closely related species: Herposiphonia akidoglossa, Herposiphonia monilifera, Herposiphonia pectinella, Herposiphonia rostrata, and Herposiphonia nuda. DNA barcoding of COI-5P sequences show that H. pectinata is clearly separated from specimens from the Hawaiian Islands and the Iberian Peninsula.