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| Bathylepeta wadatsumi Chen, Tsuda & Ishitani, 2025 |
Abstract
True limpets in the gastropod subclass Patellogastropoda are familiar members of shallow-water rocky environments but are much rarer in the deep, with just three families adapted to bathyal depths or more. Of these, Lepetidae is the only one found on ambient seafloor habitats, and Bathylepeta is a very deep genus known from two species off Chile and Antarctica. Here, we report a giant Bathylepeta up to a shell length of 40.5 mm from 5922 m deep in the northwestern Pacific and name it Bathylepeta wadatsumi sp. nov. Phylogenetic reconstruction using the mitochondrial cytochrome c oxidase subunit I (COI) gene supports the placement of this new species in Bathylepeta. Our new species is most similar to B. linseae from the Weddell Sea but can be distinguished by its much more developed second lateral and marginal teeth, as well as a larger size. Bathylepeta wadatsumi sp. nov. also has slightly imbricating radular basal plates, a feature previously unknown from this genus; we therefore emend the genus diagnosis. Our finding not only extends the distribution of this enigmatic limpet genus to Japan but also marks the deepest bathymetric record for the entire Patellogastropoda.
Key Words: COI mtDNA, Gastropoda, Lepetidae, Mollusca, morphology, new species, Patellogastropoda, phylogeny, taxonomy
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| Bathylepeta wadatsumi sp. nov., holotype (NSMT-Mo 79627). A. Dorsal view; B. Ventral view; C. Ventral view with the soft parts removed; D. Lateral view from the left; E. Lateral view from the right. |
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| Bathylepeta wadatsumi sp. nov., holotype (NSMT-Mo 79627). jaw and radula. external anatomy. |
Bathylepeta wadatsumi sp. nov.
Diagnosis. A very large (at least up to 40.5 mm SL) Bathylepeta with about 80 clearly defined white radial streaks on the shell. When alive, ventral tissue generally pigmented reddish brown, oral shield greyish, oral lappets also reddish brown. Second lateral teeth very well-developed, each as large as the fused pair of first laterals. Basal plate rectangular, slightly overlapping. Marginal teeth also very well-developed, forming overhanging, spoon-like cusps larger in size than the laterals, edges smooth. Jaw strongly mineralised and reinforced. Genital papillae small, about 0.7 mm long when alive and contracted.
Etymology. From ‘Wadatsumi’, god of the sea in Japanese mythology, alluding to its very deep habitat. It is also a reference to the fish-man character “Large Monk” Wadatsumi from Eiichiro Oda’s manga series "ONE PIECE" (Oda 2011), whose enormous body size is reminiscent of the large size that B. wadatsumi sp. nov. reaches for a deep-water patellogastropod. Used as a noun in apposition.
Chong Chen, Miwako Tsuda and Yoshiyuki Ishitani. 2025. A New large-sized lepetid Limpet from the Abyssal northwestern Pacific is the Deepest Known patellogastropod. Zoosystematics and Evolution. 101(3): 1249-1258. DOI: doi.org/10.3897/zse.101.156207
