Phylogeny and taxonomy of Prasiolales (Trebouxiophyceae, Chlorophyta) from Tasmania, including Rosenvingiella tasmanica sp. nov.

Abstract

Moniz M.B.J., Rindi F. and Guiry M.D. 2012. Phylogeny and taxonomy of Prasiolales (Trebouxiophyceae, Chlorophyta) from Tasmania, including Rosenvingiella tasmanica sp. nov. Phycologia 51: 86–97. DOI: 10.2216/10-103.1

The order Prasiolales includes trebouxiophycean green algae widely distributed in polar and cold temperate regions. Molecular data produced in recent years have shed considerable light on the phylogeny and genetic diversity of this group. Most of the information available for the order, however, has been obtained for the northern hemisphere; information for the southern hemisphere is comparatively scanty. Collections of Prasiolales were obtained from coastal sites in southern and eastern Tasmania and studied by microscopic examination, culture experiments and molecular analyses based on rbcL sequences. The results led to the discovery of a new species, Rosenvingiella tasmanica, which represents a previously unknown lineage within the genus Rosenvingiella. Culture observations and molecular data showed that collections from Tasmania previously identified as R. polyrhiza must be referred to R. constricta. This is the first record of this species for the southern hemisphere and outside of Eurasia and North America. In the same way, the molecular data revealed that the alga formerly known in Tasmania as Prasiola crispa is in fact referable to P. borealis. This organism was found both as a free-living alga and in a lichenized form similar to the original collections from North America. The rbcL gene sequence comparisons indicate a high genetic similarity between the Prasiolales of Tasmania and those of Pacific North America.

Key Words::

• Australia
• Biogeography
• Phylogeny
• Prasiola
• Prasiolales
• rbcL
• Rosenvingiella
• Tasmania
• Taxonomy
• Trebouxiophyceae

ACKNOWLEDGEMENTS

The study received financial support from the Marine Institute of Ireland as part of the National Marine Biodiscovery Programme (Beaufort Award for Marine Biodiscovery to National University of Ireland, Galway). We are very grateful to Fiona Scott for the collection of Prasiola from Lady Bay, pictures and useful information, and to Dr and Mrs G.T. Kraft for encouraging and facilitating MDG's Tasmanian fieldtrip.