A molecular-assisted investigation of diversity, biogeography and phylogenetic relationships for species of Neoptilota and Ptilota (Wrangeliaceae, Rhodophyta) reported along Canadian coasts

Abstract:

Traditional morphology-based investigations of the red algal genera Neoptilota and Ptilota (Wrangeliaceae, Rhodophyta) have struggled to provide accurate accounts of diversity, distribution and evolutionary relationships for the species reported along Canadian coasts. Consequently, there is much disagreement and taxonomic uncertainty surrounding several species within these genera. To resolve these issues we conducted a molecular-assisted investigation that included both a DNA barcode survey (COI-5P), as well as the first multigene (COI-5P, psaA, rbcL) phylogenetic analyses for these genera. To compare our taxonomic results with a previous investigation we also sequenced psbA for select species. Our phylogenetic analyses indicated that current taxonomic perspectives among members of these genera were incorrect, as the generitypes for Neoptilota and Ptilota resolved together in a lineage that also included Psilothallia dentata, with the generitype for Plumaria weakly resolved as sister to all of the previous taxa. Synonymy of Neoptilota with Ptilota was proposed, as was the transfer of Psilothallia dentata to this genus. Additionally, our molecular analyses have indicated that diversity was previously underestimated for this complex. Whereas we uncovered no differences for the Atlantic flora relative to recent studies, in the northeast Pacific we considered Ptilota californica var. californica to be synonymous with P. densa and we expanded P. filicina to include specimens previously assigned to P. californica var. β concinna. We further failed to confirm the presence of P. serrata and recorded six additional species in British Columbia: reinstatement of P. tenuis; P. gwaiihaanasica sp. nov.; P. haidarum sp. nov.; P. pseudohypnoides sp. nov.; P. sloanii sp. nov.; and, P. subita sp. nov. The implications of the taxonomic changes proposed here are discussed.

Key Words::

• COI-5P
• DNA barcoding
• Neoptilota
• Ptilota
• Wrangeliaceae

ACKNOWLEDGEMENTS

We thank the collectors listed in Table S1 for their assistance in the field, and Dan McDevit and Tanya Moore for their help in generating sequence data. We thank Dr Norm Sloan for encouraging us to study the seaweeds of Haida Gwaii. We appreciate the extensive support of Parks Canada and the Haida Nation, especially staff of the Gwaii Haanas National Park Reserve and Haida Heritage Site, while conducting our field research in this region. For providing us with images of type material and helpful taxonomic information, we extend our gratitude to Patrik Frödén at Lund University Herbarium, Jo Wilbraham and the Trustees of the Natural History Museum of London, John Parnell and Jaqueline Stone at Trinity College Dublin Herbarium, as well as Michaela Schmull and Chelsea Parise at Harvard University Herbarium. We also thank Craig Schneider, Mike Wynne and Mike Guiry for assistance in interpreting historical taxonomic literature and an anonymous reviewer for valuable insights regarding the type of Ptilota californica var. californica. This research was funded by the Natural Sciences and Engineering Research Council of Canada, the New Brunswick Innovation Foundation, The Canadian Barcode of Life Network from Genome Canada through the Ontario Genomics Institute, and through the Canadian Foundation for Innovation.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/15-141.1.s1