Phylogenetic affinities and distribution of the Hawaiian freshwater red algae (Rhodophyta)

Abstract

Carlile A.L. and Sherwood A.R. 2013. Phylogenetic affinities and distribution of the Hawaiian freshwater red algae (Rhodophyta). Phycologia 52: 309–319. DOI: 10.2216/12–097.1

The present study documents the nonmarine red algal species present in the Hawaiian Islands, including their distribution patterns and phylogenetic affinities of the most common taxa. Large-scale survey collections of freshwater algae were made throughout the six largest main Hawaiian Islands, resulting in 155 red algal isolates. Of these, 69 were used for molecular analyses, with DNA sequences generated for four markers from three genomes. Phylogenetic affinities with global reference sequences for the two most common taxa, Composopogon caeruleus (Compsopogonales, Rhodophyta) and the form genus Chantransia, were inferred in an effort to determine the origin of Hawaiian populations. Morphometric measurements and cluster analysis were used to assess the congruence between morphology and molecular data among Chantransia lineages. Phylogeographic patterns within Hawaii were examined for the most common form of Chantransia, Batrachospermum arcuatum (Batrachospermales, Rhodophyta). Seven species of freshwater red algae were found, with some new records for Hawaii. These species had contrasting distributions; some were widespread species, and others were confined to a single island. Molecular data also revealed contrasting patterns for the two most common taxa: one was widespread with no genetic variation even in the context of global sequences, and the other exhibited substantial phylogeographic structure, following the progression rule within the Hawaiian Islands. Morphometric analysis demonstrated little agreement between morphology and molecular data among Chantransia. This is the first comprehensive survey of the freshwater red algae in Hawaii and revealed 28% endemic taxa, with one putative new species reported from Kauai. Contrasting examples of global phylogeographic structure were found; the taxon from which patterns could be deduced showed a western Pacific origin. This study highlights the need for global sampling of freshwater red algae to infer dispersal patterns, especially for those algae with cosmopolitan distributions.

Key Words::

• Batrachospermum arcuatum
• Biogeography
• Chantransia
• Compsopogon caeruleus
• Freshwater algae
• Hawaii
• Phylogeography
• rbcL
• Rhodophyta
• UPA

ACKNOWLEDGEMENTS

We are grateful to numerous community members and government organizations for their assistance with access to field sites: Kawika Winter (Limahuli National Tropical Botanical Garden), Josh Pastrana, Paul Rappun, Kaua Friaola, Ane Bakutis, Kaiulani Pahio (Kanu o ka ‘Āina Public Charter School), The Nature Conservancy Molokai, the Hawaii Division of Forestry and Wildlife, and the Hawaii Division of Aquatic Resources. We thank our colleagues on the Hawaiian Freshwater Biodiversity team for their help with field collections (Dr Patrick Kociolek and Carrie Graeff from the University of Colorado at Boulder, Dr Rex Lowe from Bowling Green State University, Dr Jeff Johansen and Melissa Vaccarino from John Carroll University, and Jessica Neumann from the University of Hawaii). We are grateful to Emily Johnston for comparing our Thorea Chantransia collections to her Thorea data set to confirm our designations. We also thank Orlando Necchi Jr. for advice on primers and morphometric data. Comments from two anonymous reviewers improved the manuscript. This work was funded by the National Science Foundation grant DEB-841734 (to A.R.S. and G.G. Presting).

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/12-097.1.s1.