Taxonomic and biological notes on a species of Iphitime (Polychaeta, Eunicida) associated with Pagurusprideaux from western Norway

Abstract

On the basis of 658 specimens collected over an 11 year period, the symbiotic eunicid polychaete, Iphitime paguri Fage & Legendre, 1934, is redescribed, and its biology in its presumed preferred host, Pagurus prideaux Leach, 1815, is outlined. The main ecological part is based on sampling of Pagurus on five occasions throughout a year in Raunefjorden, southwest of Bergen. Iphitime paguri turned out to have a strong sexual dimorphism, both in outer appearance and in the morphology of the jaws. Both juveniles and mature individuals of both genders are described. The infestation rate of Pagurus prideaux was very high (as opposed to the low reported infestation rate in Pagurus bernhardus, generally regarded as the host of this species) and the symbiotic polychaetes turned out to have a distinct pattern of host utilization in different life stages. Ripe males and females were, at certain times of the year, generally found more or less intertwined in the apex of the gastropod shell inhabited by its host. Small larval stages were found in the same place. Intermediate size groups were found in the gill chamber and in a sulcus on the carapax of the pagurid host.

Keywords:

• Hermit crab
• Iphitime paguri
• Northeastern Atlantic
• redescription
• sexual dimorphism
• symbiotic polychaete

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgments

We thank Dr Lucien Laubier of Centre Océanologique de Bretagne, and Dr Y. le Gal, Assistant Director at the Laboratoire de Biologie Marine, Concarneau, France, for kindly lending a sample of Iphitime cuenoti. Dr Laubier and the curator of the Porifera and Polychaeta Section of the British Museum (Natural History) are thanked for checking the collections of Muséum d'Histoire Naturelle in Paris and the British Museum, respectively, for material of Iphitime paguri. Elin Holm has redrawn all of our sketches. Kristin Petersen is thanked for permission to use her unpublished genetic data. Danny Eibye-Jacobsen and an anonymous referee have supplied constructive and helpful comments on the manuscript.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark