A molecular assessment of species diversity and generic boundaries in the red algal tribes Polysiphonieae and Streblocladieae (Rhodomelaceae, Rhodophyta) in Canada

Sequence data generated during a Canadian barcode survey (COI-5P) of the tribes Polysiphonieae and Streblocladieae, a large and taxonomically challenging group of red algae, revealed significant taxonomic confusion and hidden species diversity. <i>Polysiphonia pacifica</i> Hollenberg, <i>P. paniculata</i> Montagne, <i>P. stricta</i> (Dillwyn) Greville and <i>Vertebrata fucoides</i> (Hudson) Kuntze were all complexes of two or more genetically distinct yet overlooked species. One variety of <i>P. pacifica</i> was elevated to the rank of species as <i>P. determinata</i> (Hollenberg) Savoie &amp; Saunders, stat. nov. Several new additions to the Canadian flora were recorded including <i>P. kapraunii</i> Stuercke &amp; Freshwater and <i>P. morrowii</i> Harvey. Subsequent multi-gene (COI-5P, LSU and <i>rbc</i>L) phylogenetic analyses confirmed that the genus <i>Polysiphonia</i> Greville was polyphyletic, and currently assigned species resolved with many other genera. <i>Polysiphonia sensu stricto</i> was restricted to a group of species that formed a monophyletic lineage with the type, <i>Polysiphonia stricta. Carradoriella</i> P.C.Silva was resurrected based on the South African species <i>Carradoriella virgata</i> (C.Agardh) P.C.Silva. Species previously attributed to <i>Polysiphonia</i> were transferred to <i>Carradoriella, Leptosiphonia</i> and <i>Vertebrata</i> as well as to three new genera described here: <i>Acanthosiphonia</i> gen. nov., based on <i>A. echinata</i> (Harvey) comb. nov.; <i>Eutrichosiphonia</i> gen. nov. for <i>E. confusa</i> (Hollenberg) comb. nov. and <i>E. sabulosia</i> (B.Kim &amp; M.S.Kim) comb. nov.; and <i>Kapraunia</i> gen. nov., which includes <i>K. schneideri</i> (Stuercke &amp; Freshwater) comb. nov. and three additional species.