In:
ZooKeys, Pensoft Publishers, Vol. 1146 ( 2023-02-07), p. 135-146
Abstract:
Monostiliferous nemerteans in the genus Tetrastemma Ehrenberg, 1828 are generally characterized as having four eyes, and they occur worldwide, from the intertidal zone to the deep-sea bottom. Recent extensive sampling of Tetrastemma has explored the high species diversity, including many undescribed forms, but phylogenic analysis has revealed non-monophyly of the genus. We herein describe three new species of the genus ( T. album sp. nov. , T. persona sp. nov. , and T. shohoense sp. nov. ) from northwestern Pacific waters based on specimens collected by dredging or by use of a remotely operated vehicle at depths of 116–455 m. Since anatomical and histological characters traditionally used in systematics of the genus are sometimes interspecifically uniform, a histology-free approach is applied for the species descriptions in this study. To confirm the generic affiliation of the new species, a molecular phylogenetic analysis based on partial sequences of cytochrome c oxidase subunit I, 16S rRNA, 18S rRNA, 28S rRNA, and histone H3 genes was performed. Our result shows that all three new species are nested in a subclade formed by species from the North Pacific and American Atlantic, inferring that geographic distribution does not reflect the cladogenesis of Tetrastemma . Furthermore, two Tetrastemma species with a cylindrical stylet basis, T. freyae Chernyshev et al., 2020 from off the coast of India and Hawaii and T. shohoense sp. nov. from Shoho Seamount, Japan, constitute a clade in the resulting tree.
Type of Medium:
Online Resource
ISSN:
1313-2970
,
1313-2989
DOI:
10.3897/zookeys.1146.95004
DOI:
10.3897/zookeys.1146.95004.figure1
DOI:
10.3897/zookeys.1146.95004.figure2
DOI:
10.3897/zookeys.1146.95004.figure3
Language:
Unknown
Publisher:
Pensoft Publishers
Publication Date:
2023
detail.hit.zdb_id:
2445640-8
SSG:
12
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