Molecular identification and phylogeny of an aquatic moss species in Antarctic lakes

Due to the morphological variability, the identification of moss species can be difficult when the plant grows in submerged environments. The taxonomic status of an aquatic moss found in lakes of the Sôya Coast region, East Antarctica, had been controversial, and then, it was investigated by molecular phylogenetic and haplotype network analysis of two chloroplast regions ( rps 4 and trn L-F) and/or the nuclear ribosomal ITS region. Based on the results of the analyses, the moss was assigned to the genus Leptobryum and determined to be conspecific with Leptobryum wilsonii (Mitt.) Broth. described from South America. Almost no genetic variation was observed between all samples from Antarctic lakes and some samples of L . wilsonii from Chile. Molecular and geohistorical evidence suggests that immigration of L . wilsonii into Antarctic lakes took place during the Holocene via long-distance dispersal from South America. This study gives a clear example of the widespread assumption that most of the Antarctic moss species are post-glacial immigrants.