A molecular survey of Ralfsia sensu stricto (Ralfsiales, Phaeophyceae) in Canada uncovers three new species: R. robertii sp. nov., R. tenebris sp. nov., and R. unimaculata sp. nov.

Abstract

Currently there are three species (i.e., traditional morphospecies) in Canada assigned to the genus Ralfsia sensu lato, which we establish is not monophyletic even after excluding “species” now known to apply to alternate stages in the life histories of non-ralfsialean species. These species include R. fungiformis (Gunnerus) Setchell & N.L.Gardner and R. pacifica Hollenberg in the Pacific, and R. fungiformis and R. verrucosa (J.E.Areschoug) J.E.Areschoug in the Atlantic. However, a DNA barcode survey of Ralfsiales in Canada using the markers COI-5P and rbcL-3P revealed five genetic groups assignable to Ralfsia sensu stricto (i.e., includes only species assigned to this genus based on phylogenetic analyses). Further complicating matters, of the three species listed previously as occurring in Canada only the type species R. fungiformis is assignable to Ralfsia sensu stricto. Ralfsia pacifica and R. verrucosa did not group with the generitype and thus are not assignable to Ralfsia sensu stricto; further, they did not group with the family Ralfsiaceae. They will be presented in a subsequent manuscript. The four other genetic groups in Canada assignable to Ralfsia sensu stricto are new species of which three are described here: Ralfsia robertii sp. nov., Ralfsia tenebris sp. nov., and Ralfsia unimaculata sp. nov. The fourth consisted of a single sterile specimen from Haida Gwaii, British Columbia, and was not characterized.