Morphological and molecular characterization of Neoralfsia hancockii comb. nov (Ralfsiales, Phaeophyceae) from topotype of San Jose del Cabo, Baja California, Mexico

摘要

To resolve the taxonomic status of Ralfsia hancockii and its relationship to related species, we have carried out a morphological and molecular study ( rbcL) on the topotype material of the species. Our analyses, using maximum parsimony and Bayesian posterior probability, located this species in a clade that is distinct and distant from other species of the genus Ralfsia and other genera of the family Ralfsiaceae, but is shared with the family Neoralfsiaceae. Morphological data confirmed that the presence of unangia with ( 2-) 3-6 stalk cells and mostly unilateral symmetry with partial bilateral development is characteristic of this species and distinguishes it from the morphologically similar Neoralfsia expansa sensu Borgesen. Similarities to N. expansa sensu Tanaka and Chihara, from which the latter species is distinguished by having paraphyses with thinner and larger basal cells, are discussed. We propose Neoralfsia hancockii comb. nov.