Molecularly assisted taxonomic studies of marine red algae from the north-western Pacific: establishing the ordinal and family positions of the genus Lukinia and the monospecific status of the genus Sparlingia (Rhodymeniales)

ABSTRACT

The main aim of our study was to determine the taxonomic position of Lukinia dissecta, the species of a monotypic genus endemic to the boreal western-Pacific Ocean preliminarily placed with some doubt by several authors in the order Gigartinales. To address its ordinal and family affinities, we sequenced the plastid rbcL marker and additionally provided critical cystocarp details. Based both on a phylogenetic analysis using Bayesian inference and a maximum likelihood approach as well as cystocarp structure, we conclude that Lukinia belongs to the family Rhodymeniaceae of the order Rhodymeniales. The critical anatomical features that support this conclusion are the carposporophytes, which develop on a stout fusion cell within a large chamber formed by a domed, ostiolate pericarp, with the carposporangia borne in a dense mass on a few distal gonimolobes and most gonimolobe cells becoming carposporangia. To explore a further issue regarding the presence of Rhodymeniaceae in eastern-Russian waters, we also sequenced the rbcL of Sparlingia stipitata in order to ascertain whether it is an independent taxon or a morphological form of the widespread S. pertusa. A comparison of the obtained sequences with those of S. pertusa available in GenBank has revealed a low divergence (1 ± 0.1%) from S. pertusa, which supports the assignment of S. stipitata populations from Russian waters to S. pertusa.

KEYWORDS:

• Boreal west-Pacific
• Molecularly assisted alpha taxonomy (MAAT)
• Rhodymeniaceae

ACKNOWLEDGEMENTS

We are extremely grateful to Dr. Gerald T. Kraft for his assistance in improving the manuscript and to divers A.S. Oskolkov, K.K. Dudka and I.N. Ivanov for their assistance in collecting seaweeds. We also thank an anonymous reviewer for valuable comments and recommendations.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

AUTHOR CONTRIBUTIONS

S.Y. Shibneva: analysis of molecular data, original concept, manuscript preparation; A.V. Skriptsova: seaweeds collection, light microscopy, manuscript preparation; A.A. Semenchenko: analysis of molecular data, manuscript preparation.

SUPPLEMENTARY MATERIAL

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

Additional information

Funding

The 56th expedition aboard the R/V Academic Oparin to the Sea of Okhotsk and Northwest Pacific was financially supported by the Ministry of Science and Higher Education of the Russian Federation. This research was carried out within the framework of the project AAAA-A18-118022290003-2 of NSCMB FEB RAS.