Phylogenetic relationships between Pelvetia and Pelvetiopsis (Fucaceae, Phaeophyta) inferred from sequences of the RuBisCo spacer region

As a basis for inferring phylogenetic relationships between Pelvetia and Pe lvetiopsis in the family Fucaceae, the complete sequences of the plastid-en coded RuBisCo spacer region were determined for all four species of Pelveti a, for the type species of Pelvetiopsis, P. limitata, and for three other f ucacean species (Ascophyllum nodosum, Fucus gardneri and F. vesiculosis). A ll trees based on the sequences of the RuBisCo spacer region showed that Pe lvetia is not monophyletic and consists of two clades, one including P. bab ingtonii, P. compressa, and P. siliquosa, the other comprising only the typ e species, P. canaliculata. P. canaliculata is not closely related to any o f the other Fucaceae studied and it may represent a monotypic genus. RuBisC o spacer sequences support the establishment of a new genus for the three P acific Pelvetia species: P. babingtonii, P. compressa and P, siliquosa. The congruence of the RuBisCo spacer data with reported nuclear rDNA 18S and I TS sequences, and with biogeographical and morphological data, indicates th at the RuBisCo spacer region, including its flanking areas, is useful for i nferring phylogenetic relationships within the Fucaceae.