Systematic revision of the widespread species Sarcodia ceylanica (Sarcodiaceae, Rhodophyta) in the Indo-Pacific Oceans, including S. suiae sp. nov.

Abstract:

The marine red algal genus Sarcodia possesses single to several flattened blades, composed of a central layer of medullary filaments, with some stellate cells remaining, flanked by two layers of subspherical to stellate cortical cells. Among the described species, S. ceylanica, previously regarded as a synonym of S. montagneana, is characterised by erect thalli composed of subdichotomously branched blades and has been widely reported from the Indian and western Pacific Oceans. Collections from various localities in the Indo-Pacific regions included many specimens fitting this broad concept of S. ceylanica but differed in blade morphology and were difficult to assign to any named species with confidence. In order to delineate the species boundaries within the suite of the specimens that morphologically resemble S. ceylanica and to clarify the phylogenetic significance of the morphological features used for separating species of Sarcodia, we used rbcL sequences to infer phylogenetic relationships among the available specimens. RbcL sequence analyses showed that the distribution of S. ceylanica is most likely restricted to its type locality Sri Lanka. The collections of S. ‘ceylanica’ analysed from Taiwan, Japan and Kenya were split into four clades and were genetically different from those collections of S. ceylanica from Sri Lanka. The molecular results also suggested that S. montagneana is distributed only in New Zealand. In addition, one new species, S. suiae S.-M. Lin & Rodríguez-Prieto, is described to accommodate specimens of S. ‘ceylanica’ from Taiwan. Records of S. ‘ceylanica’ and S. ‘montagneana’ from other locations in the Indo-Pacific regions should be regarded as doubtful until detailed morphological studies and molecular analyses of freshly collected specimens become available.

Key Words::

• Indo-Pacific Oceans
• Molecular phylogeny
• Rhodophyta
• Sarcodiaceae
• Sarcodia ceylanica
• Sarcodia suiae sp. nov.
• Taiwan
• Taxonomy

ACKNOWLEDGEMENTS

This project was supported by two grants from the National Science Council (Taiwan) (NSC 102-2628-B-019-002-MY3 and MOST 104-2621-B-019-001) to S.M.L. and two grants from the Spanish Ministry of Science and Technology (CGL2004-05556-C02-01 and CGL2008-00932). We thank Prof. Eric Coppejans for the Sarcodia collections from Sri Lanka, Li-Chia Liu and Yi-Chi Wang for assisting field collecting in Taiwan and Yu-Shan Chiou for DNA sequencing. We thank Prof. Michael Wynne for his valuable discussion on the type collections of S. ceylanica and S. ceylonensis. We acknowledge the assistance of Nimal Karunajeewa and staff at the National Herbarium of Victoria for scanning the holotype of S. ceylanica.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/16-31.1.s1.