Brooding deep-water onuphid polychaetes (Annelida) from the Bay of Biscay

Abstract

We report on three species of deep-water onuphid polychaetes (Nothria maremontana, Paradiopatra hispanica and Rhamphobrachium brevibrachiatum) from the Bay of Biscay from depths of 468 to 1186 m. The three species contained eggs and/or juveniles inside the parental tubes and R. brevibrachiatum had a cocoon-like capsule attached on the outside of its tube containing fibres and sperm. We present brief taxonomic descriptions of the three species, including some observations on ontogenetic chaetal changes in N. maremontana. The brooded eggs ranged from 300 to 340 µm in diameter in N. maremontana, while R. brevibrachiatum eggs ranged from 390 to 450 µm; juveniles consisted of 6 chaetigers for N. maremontana and 6–45 chaetigers for P. hispanica. We describe and illustrate the eggs, juveniles and sperm capsule. Although the origin of the sperm capsule is questionable, we reject the possibility of an unrelated passenger and speculate that the structures contained inside the capsule are long, thin spermatophores of a type not previously known for onuphids.

Key words:

• Avilés Canyon
• benthic fauna
• Cantabrian Sea
• direct development
• Spain
• sperm

Acknowledgements

We thank Nataliya Budaeva and Jim Blake for information and comments. We are also grateful to Nuria Anadón for assistance with SEM processing and helpful comments. Our thanks go to two reviewers for their careful reviews and helpful remarks.

Funding

AA is supported by a Severo Ochoa fellowship from the FICYT Foundation (Principado de Asturias, Spain).

Editorial responsibility: Danny Eibye-Jacobsen

Additional information

Funding

Funding: AA is supported by a Severo Ochoa fellowship from the FICYT Foundation (Principado de Asturias, Spain).