Integrative taxonomy of a new giant deep-sea caudofoveate from South China Sea cold seeps

By

Chen, Chong
Liu, Xu
Gu, Xinyu
Qiu, Jian-Wen
Sun, Jin

Type

Article

Date of Publication

2024

Original Publication

Zoosystematics and evolution

Volume

100

Pages

841--850

Subjects

Aplacophora , Caudofoveata , chemosynthetic , F site , Haima , hydrocarbon seep , Jiaolong Ridge , new species

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia Pensoft

Identifiers

DOI: https://doi.org/10.3897/zse.100.125409

 

Abstract

Caudofoveata is a class of worm-like molluscs (aplacophorans) that typically have an infaunal lifestyle, burrowing in soft bottoms in a wide range of marine habitats from shallow to deep waters. Here, we describe a very large new species of caudofoveate from South China Sea methane seeps growing up to 154 mm in length: Chaetoderma shenloong sp. nov. It is the first caudofoveate to be named from a chemosynthetic ecosystem and the first aplacophoran mollusc associated with seeps. Our new species stands out from other Pacific Chaetoderma species by its large size, a wide body relative to its length, a barely sclerotised radula, and the presence of isosceles-triangular sclerites. Phylogenetic reconstruction using the mitochondrial cytochrome c oxidase subunit I (COI) gene placed it within a paraphyletic clade comprising Chaetodermatidae and Limifossoridae, in line with a previous phylogenetic analysis. This also revealed that C. shenloong sp. nov. is conspecific with a Chaetoderma sp. whose whole genome was recently sequenced and assembled but remained undescribed until now. The most closely related species with an available COI sequence was C. felderi, the largest caudofoveate species recorded. Our discovery suggests caudofoveates may be present in other seeps globally but so far neglected; a potential example is C. felderi from the Gulf of Mexico, where seeps are abundant but whose exact habitat remains unclear.