Species recognition in New Zealand Porphyra using 18S rDNA sequencing

The long geographic isolation of New Zealand, an archipelago with a large l atitudinal range (29 degrees to 54 degrees S) and an extensive coastline, h as resulted in a high level of endemism in both land and coastal marine flo ra. The genus Porphyra in NZ is represented by 5 epiphytic species and a nu mber of epilithic species, many of which are undescribed. Systematic studie s aimed at understanding variation in morphology and life history are under way, and have led to the description of a number of new species. The presen t study uses sequence data from the 18S rDNA locus to investigate genetic v ariation in New Zealand Porphyra. Sequences have been fully determined for 10 epilithic species. A subset of these data has been shown to be sufficien t to distinguish established taxa and to identify new entities. Our data in dicate that New Zealand harbours at least 12 epilithic species of Porphyra, establishing the NZ coastline as a repository of diversity for this genus. Phylogenetic trees based on complete 18S rDNA sequence data show a deep di vision in the genus that is not obviously correlated with existing morpholo gical characters, and indicate that representatives of the New Zealand flor a have undergone long reproductive isolation.