Vol. 61, 2022

(update: 2022.5.30)

A New Branchipolynoe (Aphroditiformia: Polynoidae) Scale Worm from the Onnuri Deep-sea Hydrothermal Vent Field, Northern Central Indian Ridge

Sang Lyeol Kim^1,2, Hyeongwoo Choi³, Seong-il Eyun³, Dongsung Kim^1,2, and Ok Hwan Yu^1,2,*

¹Marine Ecosystem and Biological Research Centre, Korea Institute of Ocean Science and Technology, Busan 49111, Korea. *Correspondence: E-mail: ohyu@kiost.ac.kr (Yu).
E-mail: boyis20c@kiost.ac.kr (SL Kim); creo9447@naver.com (Choi); eyun@cau.ac.kr (Eyun); dskim@kiost.ac.kr (D Kim)
²Korea Maritime University, Busan 49111, Korea
³Department of Life Science, Chung-Ang University, Seoul 06974, Korea

Received 12 November 2021 / Accepted 3 March 2022
Communicated by Benny K.K. Chan

Deep-sea hydrothermal vents are dynamic environments with exotic fauna, including bathymodiolin mussels and scale worm annelids that are often in close association. In this study, we found a new species of Branchipolynoe (Aphroditiformia: Polynoidae) living in the recently discovered mussel Gigantidas vrijenhoeki in deep-sea hydrothermal vents and methane seeps at 2,014–2,023 m depth. Based on the
morphology and full mitochondrial genome sequences of specimens of Branchipolynoe from the Onnuri vent field (OVF) on the northern Central Indian Ridge, we describe them as a new species: Branchipolynoe onnuriensis sp. nov. This species resembles B. longqiensis and B. tjiasmantoi, but can be distinguished from these species by the shape of the notopodial acicular lobe and the tips of the subacicular
neurochaetae. This identity is well-supported by genetic distance and phylogenetic analyses based on the mitochondrial c oxidase subunit I (COI) gene, with the new species being closest to the Western Pacific species B. tjiasmantoi. Phylogenetic analyses support close relationships between the Indian Ocean and Western Pacific hydrothermal polychaetes. Our data provide a foundation for exploring the evolutionary relationship between scale worms and bathymodiolin mussels.

Key words: Chemosynthetic environment, Full mitochondrial genome, Hydrothermal vent, Mitochondrial cytochrome c oxidase subunit I (COI), Polychaeta, Taxonomy.

Citation: Kim SL, Choi H, Eyun S, Kim D, Yu OH. 2022. A new Branchipolynoe (Aphroditiformia: Polynoidae) scale worm from the Onnuri deepsea hydrothermal vent field, northern Central Indian Ridge. Zool Stud 61:21. doi:10.6620/ZS.2022.61-21.

Supplementary materials: Fig. S1丨Fig. S2丨Table S1丨Table S2丨Table S3丨Table S4丨Table S5