Abstract:
The taxonomic distinctiveness and distribution of the brown alga Colpomenia durvillei are debatable; the species was fi rst described from central Chile. We analyzed mitochondrial cox 3 and plastid rbc L sequences from specimens collected in central Chile and Sonora, Mexico, in combination with morphological observations of specimens collected in Chile, Peru, and Mexico. Compared with other elongate species of the genus, C. durvillei is distinguished by erect, elongate thalli arising from a wide colpomenioid base, up to eight layers of cortical and medullary cells, and plurilocular sporangia with many layers (up to 18 locules). In all phylogenetic analyses of cox 3 and rbc L sequences, all elongate species of the genus formed a clade, in which C. durvillei was consistently distinct from congeners. Colpomenia bullosa was closely related to C. durvillei in our cox 3 analyses, and the clade containing these two species was closely related to Colpomenia phae-odactyla. This is the fi rst report to confi rm C. durvillei by molecular data and also the fi rst report on the occurrence of the species in Sonora, Mexico. It had previously been mis-identifi ed as a variant of C. phaeodactyla on the Pacifi c coast of South America, and the name C. durvillei was misapplied to C. bullosa in New Zealand.
