Leucothoid amphipod and terebellid polychaete symbiosis with description of a new species of the genus Leucothoe Leach, 1814 (Crustacea: Amphipoda: Leucothoidae)

Abstract

The order Amphipoda is one of the largest orders in the Crustacea, many species of which are involved in symbiotic relations with other animals. Despite the considerable diversity of the Amphipoda both in number of species and ecology, polychaete-commensalism has been poorly known and described from few species. In particular, there has been little discussion of the evolutionary origins of polychaete-commensalism relationships. Amphipods in the family Leucothoidae are known as commensal inhabitants of filter-feeding invertebrates, where they utilize the feeding current produced by their hosts. Leucothoids are typically found from three types of filter-feeding hosts: sponges, ascidians, and bivalve molluscs. Relatively little is known about leucothoids that associate with other types of hosts. An undescribed species of the genus Leucothoe associated with burrows of terebellid polychaetes from Japan has been found. We herein describe this species as Leucothoe vermicola sp. nov., providing COI mtDNA and 18S rDNA sequences for DNA barcoding. This is the first record of a symbiotic association between Leucothoidae and Terebellidae. We also provide a hypothesis of the phylogenetic position of L. vermicola sp. nov. and evolution of the polychaete-commensalism in this species. The polychaete-commensalism in the present new species may have resulted from the entry of generalist species into polychaete hosts, rather than from host-conversion from a specialist species.

http://zoobank.org/urn:lsid:zoobank.org:pub:4EBA42DD-EC19-4278-B712-8BEFBC519F8F

Key words:

• Amphipoda
• commensal
• symbiosis
• Leucothoidae
• Polychaeta
• Terebellidae

Acknowledgements

We are grateful to Dr Masato Kiyomoto and Mr Mamoru Yamaguchi of the Marine and Coastal Research Center, Ochanomizu University, and Dr Masaatsu Tanaka (Keio University), for all their help in field investigations. We are grateful to Dr James Davis Reimer for providing collecting support in Shimoda. We would like to express our gratitude to Dr Toru Kobari and Dr Gen Kume (Kagoshima University) for kindly lending us their light microscope and stereomicroscope. We thank Ms Naoko Kodama (The University of Tokyo) for her support in making line drawings. Laboratory space and logistical support was provided by the Rising Star Program at the University of the Ryukyus and the Department of Biological and Environmental Sciences at Georgia College. Funding was provided to Kristine N. White by a Japanese Society for the Promotion of Science (JSPS) postdoctoral fellowship (No. P10711) and by a JAMBIO research grant to Dr James Davis Reimer. We are also grateful to Dr Yo Yamasaki (National Institute of Genetics) for his valuable suggestions on the early draft of our manuscript. We thank Traudl Krapp-Schickel (Zoologischen Forschungsmuseum Alexander Koenig) and another anonymous reviewer for their careful reading and helpful comments on our manuscript.

Supplemental material

Supplemental material for this article can be accessed on the publisher’s site at: https://doi.org/10.1080/14772000.2022.2118389

Associate Editor: Dr Polly Hayes