A DNA barcode survey of Schizymenia (Nemastomatales, Rhodophyta) in Australia and British Columbia reveals overlooked diversity including S. tenuis sp. nov. and Predaea borealis sp. nov.

Abstract

This project explored species diversity for the red algal genus Schizymenia in Australia and British Columbia, Canada, for which the only recorded representatives are S. dubyi (Chauvin ex Duby) J. Agardh and S. pacifica (Kylin) Kylin, respectively. Through a combination of CO1-5P, ITS, and rbcL sequence data, we uncovered overlooked diversity in both regions. Australian populations attributed to S. dubyi were actually a mix of an entity from the S. dubyi complex (closest matches for individuals from Argentina and Italy), a second species from the S. apoda (J. Agardh) J. Agardh complex (thus far known from Australia only), and finally individuals of the same S. dubyi mito/ITS-type introgressed with a different S. apoda rbcL type (plastid; closest matches China, Korea, and New Zealand). We resolved a complex of three closely related species for Schizymenia pacifica: Schizymenia pacifica sensu stricto, which is widely distributed in the Northeast Pacific; S. tenuis sp. nov., which is distributed throughout British Columbia with a predominantly northern distribution; and Schizymenia sp._1Cal, which is distributed from California to Oregon. As part of ongoing surveys of crustose red algae, we uncovered crustose sporophytes for three of the six Schizymenia genetic groups resolved here, and the sporophytic phase of a new species of Predaea from northern British Columbia, Predaea borealis sp. nov., for a single crustose (sporophyte) specimen from Haida Gwaii. This last result is particularly surprising, as species of Predaea are typically confined to lower latitudes in both the northern and southern hemispheres.