Diversity of Halimeda (Chlorophyta) from the Thai–Malay Peninsula

Abstract:

The Thai–Malay Peninsula separates the Andaman Sea from the Gulf of Thailand. This barrier is known to affect species distribution and genetic diversity of marine organisms. Biodiversity studies need a correct species taxonomy to interpret their biogeography; this is especially relevant in marine algae where morphological characters are few or cryptic. We address species distributions of the important macroalgal genus Halimeda. The combination of morphological data and chloroplast tufA gene sequences were used to identify species, and to reveal the variation among Halimeda species around the Thai–Malay Peninsula. The morpho-anatomical and molecular analysis showed eight species of Halimeda in Thai and Malaysian waters: Halimeda borneensis, H. discoidea, H. gigas, H. macroloba, H. micronesica, H. minima, H. opuntia, H. renschii, and two undescribed species. Three species, H. minima, H. renschii and H. micronesica, were reported for the first time from the area. Species variation was much greater in the Andaman Sea than in the Gulf of Thailand. Our results show great variation in species composition and genetic variation between the two sides of the peninsula, which could be due to differences in sea-surface currents and environmental differences between the two sides of this important marine barrier.

Key Words::

• Bryopsidales
• Chlorophyta
• Geographic barrier
• Halimeda
• Molecular phylogeny
• Sea-surface current
• Southeast Asia
• Species composition
• Thai–Malay Peninsula
• tufA

ACKNOWLEDGEMENTS

This work was supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, a scholarship for an oversea research study, PSU and Graduate School, Prince of Songkla University, Thailand. We are appreciative to Professor Dr. Khanjanapaj Lewmanomont, Ms Thidarat Noiraksar for valuable guidance, providing specimens and additional information. We thank the seaweed and seagrass research unit of Prince of Songkla University for help with fieldwork and comments throughout the study, the Institute of Ocean and Earth Sciences of the University of Malaya, and Kobe University, Research Center for Inland Seas, Japan for facilities during our visit.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/14-108.1.s1.