A new genus and species from the North Atlantic, Archestenogramma profundum (Phyllophoraceae, Rhodophyta), with taxonomic resolution of the orphaned Leptofauchea brasiliensis

A recent collection of a red alga from Bermuda showed great similarities to Leptofauchea brasiliensis from Brazil, providing the impetus for a morphological and anatomical evaluation of the two. Based on these studies, the two appear to be congeneric. Molecular phylogenetic analyses of the Bermudian plants showed them to be to be a new genus and species of the Phyllophoraceae (Gigartinales), Archestenogramma profundum C. W. Schneider, Chengsupanimit & G. W. Saunders. In light of our anatomical observations, our phylogenetic results also proved instructive as to the disposition of L. brasiliensis, a species that was suggested to be incorrectly assigned to the Rhodymeniales for over a quarter of a century and even recently excluded from Leptofauchea. The morphological and anatomical similarity of L. brasiliensis to A. profundum suggested its movement from the Faucheaceae to a new taxonomic placement in the Phyllophoraceae, as A. brasiliense (A. B. Joly) C. W. Schneider, Chengsupanimit & G. W. Saunders, comb. nov.