Four new species of Ctenodrilus, Raphidrilus, and Raricirrus (Cirratuliformia, Annelida) in Japanese waters, with notes on their phylogenetic position

Naoto Jimi; Shinta Fujimoto; Yoshihiro Fujiwara; Kohei Oguchi; Toru Miura

doi:10.7717/peerj.13044

Four new species of Ctenodrilus, Raphidrilus, and Raricirrus (Cirratuliformia, Annelida) in Japanese waters, with notes on their phylogenetic position

PeerJ. 2022 Mar 8:10:e13044. doi: 10.7717/peerj.13044. eCollection 2022.

Authors

Naoto Jimi^{1

2}, Shinta Fujimoto³, Yoshihiro Fujiwara⁴, Kohei Oguchi^{5

6}, Toru Miura⁶

Affiliations

¹ Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, Japan.
² Centre for Marine & Coastal Studies, Universiti Sains Malaysia, Penang, Malaysia.
³ Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Aomori, Japan.
⁴ Research Institute for Global Change (RIGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan.
⁵ National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
⁶ Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Japan.

Abstract

Four new species of annelids, Ctenodrilus japonicus sp. nov., Raphidrilus misakiensis sp. nov., Raphidrilus okinawaensis sp. nov., and Raricirrus anubis sp. nov., are described based on specimens collected from Japanese waters. Ctenodrilus japonicus sp. nov. inhabits the interstitial environment and can be distinguished from the other congeners by the following features: (i) total of 16 chaetigers, (ii) chaetigers 1-3 with stout hooks, (iii) minute body (approximately 1 mm in length), (iv) all parapodia with the same number of chaetae (two notochaetae; two neurochaetae), and (v) presence of dorsal and ventral papillae. Raphidrilus misakiensis sp. nov. lives under intertidal stones and can be distinguished from other congeners by having pectinate neurochaetae. Raphidrilus okinawaensis sp. nov. inhabits the interstitial environment and can be distinguished from other congeners by: (i) absence of annulation on the peristomium and achaetous segment and (ii) presence of a heart body in chaetigers 4-5. Raricirrus anubis sp. nov. inhabits whale bones and can be distinguished from other congeners by the following features: (i) presence of a heart body in chaetigers 9-14, (ii) presence of capillary neurochaetae on chaetiger 1, and (iii) presence of simple curved spines. A phylogenetic tree based on partial sequences of cytochrome c oxidase subunit I and 16S rRNA from the new species and other cirratulid worms showed that Raphidrilus is included in Cirratuliformia. This is the first record of Raphidrilus and Raricirrus from Japanese waters.

Keywords: Annelida; Japan; New species; Pacific Ocean; Polychaeta; Taxonomy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Annelida*
East Asian People
Humans
Phylogeny
Polychaeta*
RNA, Ribosomal, 16S
Whales

Substances

RNA, Ribosomal, 16S

Grants and funding

This study was funded by JSPS KAKENHI (grant number 19J00160) and Environment Research and Technology Development Fund (Grant Number: JPMEERF20204R01) of the Environmental Restoration and Conservation Agency of Japan to Naoto Jimi. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.