Molecular and morphological variation of the red alga Spyridia filamentosa (Ceramiales, Rhodophyta) in the Hawaiian Archipelago

Abstract

Conklin K.Y. and Sherwood A.R. 2012. Molecular and morphological variation of the red alga Spyridia filamentosa (Ceramiales, Rhodophyta) in the Hawaiian Archipelago. Phycologia 51: 347–357. DOI: 10.2216/10-26.1

Genetic information is proving to be important in conservation and management efforts that involve cryptic species and their role in native ecosystem restoration. Previous molecular studies have demonstrated that the red alga Spyridia filamentosa consists of several cryptic species. Spyridia filamentosa is considered to be a native species in Hawai‘i and was recently used in preliminary seagrass meadow restoration efforts in Maunalua Bay, O‘ahu. It became necessary to understand the genetic diversity of this species in the Islands and determine if there are relationships between any molecular clades of S. filamentosa and anatomical characters that might be useful (e.g. sediment capture) in habitat remediation. Both molecular and morphological (determinate branch cell dimensions) analyses revealed the presence of multiple S. filamentosa clades in Hawai‘i. Nuclear [partial LSU (large subunit)] sequence and determinate branch cell data recovered two broad lineages (I and II), which are known worldwide. The mitochondrial sequence (cox2-3 spacer) data further separated samples into five distinct clades and indicated that S. filamentosa arrived in Hawai‘i on at least six occasions. These results aided decisions made concerning preliminary experiments involved in seagrass habitat remediation and emphasized the importance of genetically evaluating cryptic species that are being considered for use in native ecosystem restoration or conservation.

Key Words::

• Anatomy
• Biogeography
• Ceramiales
• cox2-3 spacer
• Ecological restoration
• Hawai‘i
• LSU rRNA
• Rhodophyta
• Spyridia filamentosa

ACKNOWLEDGMENTS

We would like to thank the staff of the Bernice P. Bishop Museum (Honolulu), especially Napua Harbottle, for assistance and support of molecular analyses of archived material. We would also like to thank A. Kurihara, K. Peyton, T. Sauvage, E. Conklin, and D. O'Doherty for providing additional Hawaiian samples as well as A. Kato (samples from Senaga Island, Japan), Y. Yamagishi (sample from Inno-shima, Japan), H. Kawai, S. Ichiki, and S. Shimada (sample from Bonin Islands, Japan), and A. Rivera (sample from Moorea, French Polynesia). The manuscript was greatly improved through suggestions from two anonymous reviewers and Associate Editor G. C. Zuccarello. This study was supported by a grant from the U.S. National Science Foundation to A.R. Sherwood and G.G. Presting (DEB-0542608).