Phylogenetic relationships of some European Gelidium (Gelidiales, Rhodophyta) species, based on rbcL nucleotide sequence analysis

In the absence of reliable taxonomic characters, species relationships in Gelidium (Gelidiales, Rhodophyta) are poorly understood. In order to produce an independent data set for developing phylogenetic hypotheses and consequently a more natural classification of the genus, the methods and primers for sequencing rbcL were developed and used in a study of 37 Gelidium species and populations. Sequence data from 24 European and 13 non-European taxa were obtained and analyzed using parsimony methods. All European taxa were resolved in a single major clade except for Gelidium pusillum (Stackhouse) Le Jolis, which formed a separate clade within the non-European species. Populations initially identified as G. latifolium (Greville) Bornet et Thuret from Aramar, Spain and G. pulchellum (Turner) Kützing from Mallorca, Spain were found to be respectively G. attenuatum (Turner) Bornet in Thuret and what may represent an endemic Mediterranean species. European G. pusillum was distinct from taxa representing G. crinale (Turner) Lamouroux or G. pulchellum and all taxa assigned this name from other geographic regions.