Nautiliniellidae (Annelida) from Costa Rican cold seeps and a western Pacific hydrothermal vent, with description of four new species

Abstract

Four genera and five species of Nautiliniellidae (Phyllodocida; Annelida), representing four new species and one new record, were found in association with bivalves belonging to Mytilidae (Bathymodiolus spp.), Solemyidae (Acharax sp.) and Vesicomyidae (Calyptogena and Vesicomya) from hydrothermal vents of the western Pacific (Lau back-arc basin) and cold seeps of the eastern Pacific (Costa Rica). Iheyomytilidicola lauensis n. sp. is characterized by the presence of unidentate hooks; Laubierus alvini n. sp. has long dorsal cirri and notoacicula not protruding in any segment; Natsushima sashai n. sp has bifurcate chaetae with distal teeth markedly different in length and width between each other; and Shinkai fontefridae n. sp. differs in having posterior hooks with subdistal spines. Sexual dimorphism is described for Shinkai and Natsushima species and confirmed by DNA sequencing (Cytochrome c oxidase subunit I sequences). In addition, one specimen of N. bifurcata Miura & Laubier, 1990 from the Gulf of Cádiz has been studied to compare it morphologically and genetically with N. sashai n. sp. Scanning electron and optical microscopy images are provided for each species, as well as pictures of live animals. Morphological features described and documented for the first time include the presence of internal longitudinal chambers within chaetae and possible evidence that the simple chaetae, characteristic of nautiliniellids, may be derived from compound chaetae.

Key words:

• cold seeps
• dimorphism
• hydrothermal vent
• molecular taxonomy
• Nautiliniellidae
• new species
• symbiosis
• systematics

Acknowledgements

Collection and analysis of the Costa Rica nautiliniellids for this project was funded by the US National Science Foundation (NSF) to Lisa Levin and GWR (OCE-0826254 and OCE-0939557). The authors are grateful to Chief Scientist L. Levin, the captain and crew of the RV Atlantis and the crew of the HOV Alvin for crucial assistance in specimen collection. The authors also thank Bob Vrijenhoek, Chief Scientist of the cruise to the Lau and North Fiji hydrothermal vents in May–June 2005, for inviting GWR on board. Thanks also to the captain and crew of the RV Melville, and the crew of the ROV Jason II for collecting the specimens (funded by NSF grants to R.C. Vrijenhoek OCE-0241613, and to C.L. Van Dover OCE-0350554). This study was also supported by TAWNI ChEss and Fondation Total grant given to MTA for a stay at SIO and so allowed participation on a cruise to Costa Rica. Funding was also provided to MTA for the project ‘Caracterización Taxonómica y Sistemática de la familia Syllidae (polychaeta) basada en datos moleculares y morfológicos. El problema de las especies cosmopolitas y Biodiversidad en el Pacífico’ by the ‘Ministerio Ciencia e Innovación’ of the Spanish Government, Project number CGL2009-12292 BoS.

Many thanks to Ascensao Ravara who kindly permitted us to study and sequence the DNA of one Natsushima bifurcata specimen from the Gulf of Cádiz. Additionally, we greatly appreciate all the help and interesting scientific discussions on the topic to Guillermo San Martín, Alejandro Oceguera-Figueroa, Liz Borda, and Jesús Marugán. Finally, we are very grateful for the shipboard assistance of José Carvajal, Erik Cordes, Danwei Huang and Victoria Bogantes who kindly and very efficiently helped with the messy job of dissecting the bivalves and preserving the material.