Predaea rosa sp. nov. (Nemastomatales, Rhodophyta): a cool-temperate species from southern New Zealand

Abstract:

A new species of Predaea (Rhodophyta, Nemastomatales) was discovered from collections made in Fiordland, the southwestern region of the South Island, New Zealand (c. 45°S). This is the southernmost record of the genus and the highest-latitude discovery of Predaea gametophytes in the world. Predaea rosa sp. nov. is described based on both anatomical and molecular-sequence analyses. Distinguishing features include compressed blades, a lack of cortical “gland” cells, a distal bulge or small sterile cell produced on the basal cell of the carpogonial branch, clusters of nutritive cells on the cell on either side of the auxiliary cell and a gonimoblast initial that arises on the auxiliary cell opposite the point of lateral fusion of the diploidising connecting filament. In both the nSSU and the rbcL analyses, Predaea was recovered as a monophyletic genus, and the New Zealand species was resolved within it with strong support. The nSSU analysis further showed P. rosa to clearly differ from the southeastern Australian P. aurora. In the rbcL analysis, P. rosa was recovered as sister to a well-supported clade containing P. kraftiana from eastern Australia and other Pacific species from Hawaii and New Caledonia.

Key Words::

• Fiordland
• Macroalgal diversity
• Molecular phylogeny
• Nemastomatales
• Nemastomataceae
• New Zealand
• Predaea sp. nov.
• Red algae
• Systematics
• Taxonomy

ACKNOWLEDGEMENTS

We would like to thank Associate Professor Catriona Hurd for enabling participation of WN in the field work at Doubtful Sound and her funding (Performance Based Research Fund, Department of Botany, University of Otago). Thanks go to the dive team Chris Hepburn (University of Otago), Chris Cornwall (now University of Western Australia) and Derek Richards (now Te Rūnanga o Ngāi Tahu) for their excellent field observations and collections. We thank Roberta D'Archino (NIWA) for material from Dusky Sound and for providing advice and reading the manuscript; Craig Stevens and Joe O'Callaghan (NIWA) for discussions about water conditions in the fiords; Erika Mackay for preparing the plates; and Dr Gerry Kraft and an anonymous reviewer for constructive comments. This research was funded by NIWA under the Coasts & Oceans Research Programme 2 (Marine Biological Resources).