Cryptic diversity and phylogeographic patterns in the Asparagopsis armata species complex (Bonnemaisoniales, Rhodophyta) from New Zealand

ABSTRACT

Molecular techniques have become important tools to investigate cryptic diversity and phylogeographic patterns. Mitochondrial markers have revealed that the temperate red alga Asparagopsis armata contains two cryptic clades. The A. armata species complex is native to Australia and New Zealand and has been introduced around the world, particularly to Europe. Previous sequencing has focused on A. armata outside of its native range, and there are few sequences available from Australia and New Zealand. Our study investigated cryptic diversity and phylogeographic patterns for over 60 individuals from 7 locations around New Zealand using the mitochondrial cox2-3 spacer and plastid rbcL markers, and found that both cryptic clades within A. armata (L1 and L2) can be found in New Zealand. For the first time, our study has revealed haplotype variation (A and B) within each of the two cryptic A. armata clades. Asparagopsis armata L1A has been found in Australia, Europe and South Africa and is the only invasive lineage currently known, while A. armata haplotype L1B is found throughout New Zealand. In addition, A. armata L2A has been found only in Australia, and A. armata L2B has a southern distribution in New Zealand. The two mitochondrial lineages from New Zealand (L1B and L2B) were found to coexist in several locations. Further work is needed to characterize any differences in the morphology, physiology and biochemistry of the four genetically distinct mitochondrial lineages within the two cryptic clades, as well as their geographic and ecological distributions.

KEYWORDS:

• Falkenbergia
• Haplotype diversity
• Invasive red macroalgae
• Native red macroalgae
• Species delimitation models

ACKNOWLEDGEMENTS

We thank Chris Hepburn (expedition leader), Bill Dickson & Mark Elder (skippers) and all other crew members (especially Lucy Coyle, Gaya Gnanalingam, Niall Pearson, Will Pinfold & Daniel Pritchard), who participated in the Stewart Island and Fiordland voyages on the Polaris II in 2019. We also thank Andrew Forsythe for supplying algal samples and Jeff Forman and Jon Stead for boating and diving support in the Marlborough Sounds. Lastly, we thank the staff of the herbarium (especially Antony Kusabs) of the Museum of New Zealand Te Papa Tongarewa (WELT) for curating voucher specimens. Some of the phylogenetic analyses were performed on the Rāpoi High-Performance Computing facility of Victoria University of Wellington.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

SUPPLEMENTARY MATERIAL

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was partially supported by CH4-global and NIWA SSIF Coasts & Oceans, Marine Biodiversity.