First eumonostiliferous nemertean from the Nishi-Shichito Ridge, Genrokunemertes obesa gen. et sp. nov. (Eumonostilifera, Nemertea)

PeerJ

article

Natsumi Hookabe¹  Keita Koeda²  Yoshihiro Fujiwara³  Shinji Tsuchida³  Rei Ueshima¹ 

[1] Department of Biological Sciences, Graduate School of Science, The University of Tokyo;Faculty of Science, University of the Ryukyus;Research Institute for Global Change ,(RIGC), Japan Agency for Marine-Earth Science and Technology

关键词: Seamount;    Benthic;    Systematics;    Phylogeny;    Deep sea;    Trap;    Ribbon worm;   

DOI  :  10.7717/peerj.13857

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Nemerteans are mostly marine, benthic invertebrates, inhabiting intertidal to hadal zones. Recently, they have been recognized from deep sea with environmental DNA (eDNA) metabarcoding of sediment samples whereas any records from the locations and/or the water depth have not been documented in nemertean taxonomic publications to date. It suggests that there are major gaps between deep-sea nemertean fauna observed with eDNA and taxonomic knowledge. During a research expedition in 2021, we obtained a single specimen of eumonostiliferous nemertean from the southern part of Genroku Seamount Chain, the Nishi-Shichito Ridge, where any nemertean species have never been reported. Subsequent morphological and molecular examination reveal that the species is placed in a new genus and herein described as Genrokunemertes obesa gen. et sp. nov. It resembles shallow-water-dwelling Kurilonemertes and Typhloerstedia, but differs from the former in lacking eyes and the latter in possessing well-developed cephalic glands and lacking accessory nerves of lateral nerve cords. In terms of genetic distances based on partial sequences of the cytochrome c oxidase subunit I gene, G. obesa gen. et sp. nov. is closest to Monostilifera sp. Owase collected from Japan, which is characterized by large four eyes; the COI distance is higher than commonly observed interspecific divergences in eumonostiliferans.

【 授权许可】

CC BY