Vol. 64, 2025

Two New Genera and Species of Polynoidae (Annelida: Polychaeta) Associated with Sea Urchins

Naoto Jimi^1,2,*, Natsumi Hookabe³, Sau Pinn Woo², and Hisanori Kohtsuka⁴

¹Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, 429-63 Sugashima, Toba, Mie 517-0004, Japan. * Correspondence: E-mail: beniimo7010@gmail.com (Jimi)
²Centre for Marine & Coastal Studies, Universiti Sains Malaysia 11800 USM, Penang, Malaysia. E-mail: woosaupinn@usm.my (Woo)
³Research Institute for Global Change (RIGC), JAMSTEC, Yokosuka, Kanagawa 237-0061, Japan. E-mail: sofeechan312@gmail.com (Hookabe)
⁴Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa, 238-0225, Japan. E-mail: kohtsuka@g.ecc.u-tokyo.ac.jp (Kohtsuka)

(Received 9 October 2024 / Accepted 16 April 2025 / Published -- 2025)
Communicated by James D. Reimer

Symbiotic relationships between polychaetes and marine invertebrates are well-documented, with echinoderms–primary starfish and sea cucumbers–as common hosts and sea urchins being more rarely involved. Although many sea urchins possess venomous spines that are effective defenses and make them suitable hosts for symbionts, the dense packing of these spines difficult hosting symbiotic polychaetes. In this study, we describe two new genera and species of polynoid polychaetes found in association with two different species of sea urchins, collected through dredging from Sagami Bay, Japan. Echinophilia gen. nov. is characterized by an elongated body, 12 pairs of elytra, subdistally inflated antennae and dorsal cirri. Paraechinophilia gen. nov., in contrast, has a non-elongated body, 12 pairs of elytra, not inflated antennae and dorsal cirri. Additionally, we provide insights into their phylogenetic relationships based on four gene sequences (COI, 16S, 18S, and 28S).

Keywords: Annelida, Polychaeta, Symbiosis, Scaleworm, NW Pacific

Citation: Jimi N, Hookabe N, Woo SP, Kohtsuka H. 2025. Two new genera and species of Polynoidae (Annelida: Polychaeta) associated with sea urchins. Zool Stud 64:21.

We follow the code of the International Commission on Zoological Nomenclature, taxonomic papers with new species/genus descriptions will not have early view version.