| Abstract: | We report partial 18S ribosomal DNA sequences of Analipus japonicus (Harvey) Wynne and Ralfsia fungiformis (Grunnerus) Setchell et Gardner. These sequences were compared with the corresponding sequences of 13 brown algae representing six phaeophycean orders: Dictyotales, Ectocarpales, Fucales, Laminariales, Sphacelariales, and Syringodermatales. These 15 brown algae included 10 ectocarpoids representing nine ectocarpacean (sensu Gabrielson et al. 1989) families: Chordariaceae, Dictyosiphonaceae, Ectocarpaceae, Elachistaceae, Heterochordariaceae, Leathesiaceae, Punctariaceae, Ralfsiaceae, and Scytosiphonaceae. We addressed the controversial taxonomic placement of A. japonicus and R. fungiformis in the Ectocarpales by analysis of DNA sequences. Neighbor-joining and maximum parsimony-inferred phylogenies provided evidence that A. japonicus and R. fungiformis are not closely associated with the other representatives of the Ectocarpales. Bootstrap analyses suggest polyphyly of the order Ectocarpales (sensu Gabrielson et al.). However, our analysis failed to resolve the phylogenetic relationship between A. japonicus and R. fungiformis. Our results suggest that the ectocarpoids are just as distantly related to A. japonicus and R. fungiformis as they are to members of the advanced orders Desmarestiales, Dictyotales, Fucales, Laminariales, Sphacelariales, and Syringodermatales. |
