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| Acanthotrochus verruciosseous Ogawa, Chen & Sigwart, 2025 |
A new species of the rarely seen myriotrochid holothurian genus Acanthotrochus, Acanthotrochus verruciosseous sp. nov., is described from 5272 to 5325 m deep in the Aleutian Trench, North Pacific Ocean. The new species is morphologically clearly separated from three valid congeners based on acanthotrochid-type wheel ossicles bearing multiple low knobs on the inner and outer rims as well as the outward teeth. The outer, concave side of the acanthotrochid-type wheels also form inward-pointing protrusions at the base of spokes at the inner rim edge. These ossicle features have never been observed in the three described species. Acanthotrochus has a global distribution, in the North Atlantic, Indian Ocean, and Antarctica, with a maximum depth of 3320 m. Our discovery is the first record of Acanthotrochus from the North Pacific and from the lower abyssal zone, which greatly extends the known geographic and bathymetric range of Acanthotrochus. Partial mitochondrial 16S ribosomal DNA sequences from the type specimens of A. verruciosseous sp. nov. are clearly separated from the type species of the genus, Acanthotrochus mirabilis Danielssen and Koren, 1881.
Acanthotrochus verruciosseous sp. nov.
Ogawa, Akito; Chen, Chong and Sigwart, Julia D. 2025. A New abyssal Species of Acanthotrochus (Holothuroidea: Apodida) from the Aleutian Trench, North Pacific Ocean. Bulletin of Marine Science. DOI: doi.org/10.5343/bms.2025.0092
