| Abstrakt: |
Filamentous snow algae in the green algal class Trebouxiophyceae have been historically attributed to at least three genera: Raphidonema Lagerh., Koliella Hindák, and Stichococcus Nägeli. Their separation has been based on filament length and dissociation, and the shape of the terminal cells. However, the strong morphological plasticity of this material has been known since at least the 1970s, and a recent revision placed almost all of the known strains isolated from snow and ice globally into three species of Raphidonema: R. catena Leya & Yakimovich, R. nivale Lagerh., and R. sempervirens Chodat. In addition to three previously sequenced strains from New Zealand, we recently established 11 strains from snow collected throughout the Southern Alps (Fiordland, Otago, Canterbury, and Westland). Sequence data from the rbcL gene and the ITS2 rRNA region placed all of these strains into the species Raphidonema sempervirens. Some biogeographic structure is evident in the rbcL data, with New Zealand strains of the main subclade robustly split from strains isolated from the Northern Hemisphere (Europe, Iceland, Svalbard, North America). The other subclade of R. sempervirens also includes some New Zealand strains, and this subclade could become recognised as a separate species with more data and analysis. [ABSTRACT FROM AUTHOR] |
