Molecular identity, morphology and taxonomy of the Rhynchospio glutaea complex with a key to Rhynchospio species (Annelida, Spionidae)

Abstract

Rhynchospio glutaea (Ehlers, 1897), Rhynchospio arenincola Hartman, 1936 and Rhynchospio arenincola asiatica Chlebovitsch, 1959, originally described from Strait of Magellan, California, and South Kurile Islands respectively, appear similar to each other in adult morphology. These species and subspecies have been considered by some authors as subjective synonyms and are here referred to as members of the R. glutaea complex. Sequence data of four gene fragments (2465 bp in total) of the mitochondrial 16S rDNA, nuclear 18S and 28S rDNA, and Histone 3 have shown that R. glutaea complex individuals from the South West Atlantic (Argentina), North East Pacific (British Columbia and Oregon) and North West Pacific (South Korea) were genetically distant and not conspecific. These data also indicate that R. arenincola from North America and R. aff. asiatica from South Korea are more closely related to each other, and both are closer to R. glutaea from South America than to R. nhatrangi from Vietnam: nhatrangi (glutaea (arenincola-aff. asiatica)). Adults of the R. glutaea complex are hermaphrodites and the arrangement of gametes is suggested to be a crucial reproductive character for distinguishing these species. Based on this character, two species of the complex are apparent in the North West Pacific: R. asiatica Chlebovitsch, 1959 stat. nov. from the Kurile Islands (not analysed here) and an unnamed species from the mainland coast of Asia (here referred to as R. aff. asiatica). Adult morphology of R. asiatica stat. nov. is briefly described and illustrated. The lectotype and the type locality of the species on Iturup Is. are established for the first time. An identification key is provided to the 10 currently recognized Rhynchospio species.

Key words:

• hermaphroditism
• identification key
• molecular analysis
• polychaetes
• sibling species

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Corrigendum

Acknowledgements

Our sincere thanks are to Jose Maria (Lobo) Orensanz, Graham Gillespie, John W. Chapman and Edwin D. Grosholz for providing generous support for collecting and examining polychaetes in Argentina, Canada and USA, respectively. Our sincere gratitude is also to Sergey Y. Gagaev and Vyatcheslav V. Potin for providing information about type specimens of R. arenincola asiatica, John W. Chapman, Lawrence L. Lovell and two anonymous reviewers for valuable comments and editing the manuscript.

Associate Editor: Adrian Glover

Additional information

Funding

Financial support was provided by the Russian Ministry of Education and Science (Grant P727, N 02.740.11.0875), Russian Foundation for Basic Research (Projects 12-04-00609, 14-04-10013), Government of the Russian Federation (Projects 11.G34.31.0008, 11.G34.31.0010), the Far East Branch of the Russian Academy of Sciences (Projects 14-III-B-06-047, 14-III-D-06-016) and the Korea Institute of Ocean Science and Technology (Project PO01135).