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Issue: Vol. 5722 No. 2: 19 Nov. 2025
Type: Article
Published: 2025-11-19
DOI: 10.11646/zootaxa.5722.2.6
Page range: 265-277
Abstract views: 82
PDF downloaded: 30

Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep

College of Arts and Sciences; J. F. Oberlin University; Machida; Tokyo 194-0294; Japan
Research Institute for Global Change (RIGC); Japan Agency for Marine-Earth Science and Technology (JAMSTEC); Yokosuka; Kanagawa 237-0061; Japan
Sugashima Marine Biological Laboratory; Graduate School of Science; Nagoya University; Sugashima; Toba; Mie 517-0004; Japan; Centre for Marine & Coastal Studies; Universiti Sains Malaysia 11800 USM; Gelugor; Penang; Malaysia
Research Institute for Global Change (RIGC); Japan Agency for Marine-Earth Science and Technology (JAMSTEC); Yokosuka; Kanagawa 237-0061; Japan
Research Institute for Global Change (RIGC); Japan Agency for Marine-Earth Science and Technology (JAMSTEC); Yokosuka; Kanagawa 237-0061; Japan
Platyhelminthes Acotylea chemosynthesis-based ecosystem Leptoplanoidea systematics turbellarian

Abstract

Polyclad flatworms are free-living platyhelminths that inhabit various marine environments; however, their biodiversity in the deep sea remains poorly understood. Herein, we describe a new species of Notocomplana Faubel, 1983, Notocomplana profunda sp. nov., based on specimens collected from Bathymodiolus mussel aggregations in a deep-sea hydrocarbon seep off Hatsushima, Japan. This is the first report of a bathyal species of Notocomplana, which is dominated by shallow-water species. The new species is characterized by the absence of tentacles, eyespots, and any color pattern on the dorsal surface of the body and the presence of a seminal vesicle larger than a prostatic vesicle and a long, tubular Lang’s vesicle. A molecular phylogenetic analysis based on the partial sequences of two mitochondrial and two nuclear genes suggested that the strategy of N. profunda sp. nov. to use mussel aggregations was acquired by its shallow coastal ancestors.

 

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How to Cite

Oya, Y., Hookabe, N., Jimi, N., Furushima, Y. & Fujiwara, Y. (2025) Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa, 5722 (2), 265–277. https://doi.org/10.11646/zootaxa.5722.2.6