A taxonomic assessment of Pyropia hiemalis (Kylin) Varela-Álvarez, Guiry & Serrão, comb. nov. (Bangiaceae, Bangiophyceae)

Until recently, all the bladed members of the Bangiaceae Duby were assigned to the genus Porphyra C.Agardh, nom. cons.; however, in the last twenty years, major molecular taxonomic revisions of this family have resulted in several new and reinstated genera. Porphyra linearis Greville is one of the species retained in Porphyra and its growth and reproduction is confined to the upper intertidal in the colder months of the year. Porphyra hiemalis Kylin was described for specimens collected from the south-west coast of Sweden but was later referred to the synonymy of P. linearis based upon its winter seasonality and linear form. We here compare the morphology and reproduction of isolates of both taxa from various locations in the NE Atlantic, and we sequence the intergenetic RUBISCO spacer and adjacent coding regions in these isolates to verify their phylogenetic relationships with other members of bladed Bangiaceae. Results show that both entities are not only distinct species despite almost identical external morphology, but they belong to different genera. A lectotype and epitype (of sequenced material) is designated for P. hiemalis and a transfer to the reinstated genus Pyropia J.Agardh is proposed as Pyropia hiemalis (Klyin) Varela-Álvarez, Guiry & Serrão, comb. nov.