A new species of the fish-parasitic isopod family Cymothoidae is described from the eastern Seto Inland Sea, western Japan. Nerocila domotoae sp. nov. is found from the caudal fins of silver croaker Pennahia argentata (Houttuyn, 1782) and Japanese whiting Sillago japonica Temminck and Schlegel, 1843. This new species is distinguished from all other species of Nerocila Leach, 1818 with serrate uropodal endopods by having the following traits: cephalon 0.8 times as long as wide, anterior margin rounded; antennule bases separated; antenna article 4 without dense cluster of setae on posterodistal margin; mandible palp article 3 with 1 long and 2–4 short terminal setae; maxilla with 2 recurved robust setae on medial lobe and 2 or 3 on lateral lobe; maxilliped palp article 3 with 3 recurved robust setae at tip and 1–3 on medial margin; pereopod 6 merus inferior margin with single robust seta in each of lateral and medial rows (i.e., 1 + 1), carpus inferior margin with 3 + 1 or 3 + 2 robust setae; pereopod 7 ischium inferior margin with single row of 1 or 2 robust setae, merus inferior margin with 2–4 + 3–5 (5–9 in total) robust setae, carpus inferior margin with 3–5 + 1–3 (5–7) robust setae; three light brown stripes on dorsal surface; pleotelson lateral margins convex, posterior margin converging to weak caudomedial point; uropodal endopod medial margin with notch, lateral margin with moderate to deep serration.
A new species of Flabelligeridae is described from Japanese deep-sea waters. Ilyphagus salazarvallejoi sp. nov. has needle-shaped neurochaetae tips and palps with lobes. A mitochondrial cytochrome c oxidase subunit I barcode sequence was obtained from the holotype and deposited in GenBank. This finding represents the first record of Ilyphagus Chamberlin, 1919 from Japan and the western Pacific, and an identification key to Ilyphagus species is provided.
A single specimen of Parupeneus moffitti Randall and Myers, 1993, known formerly only from three type specimens collected from the Mariana Islands, was collected off Kitadaito Island, Daito Islands, southern Japan in August 2025. The former specimen therefore represents the second record of the species, and first from Japanese waters. A full description of the specimen and limited genetic analysis is provided, indicating a possible sister relationship of P. moffitti to Parupeneus chrysonemus (Jordan and Evermann, 1903). The pairwise distance (5.1%) between the two taxa justified their interspecific differentiation. The new standard Japanese name “Kotou-himeji” is proposed for the species.
A moray eel [192.8 mm total length (TL)], collected in February 2025 from a mud and scattered rock slope at 1 m depth in the Yoshikawa Fishing Port, Konan City, central Kochi Prefecture, Japan, was identified as Gymnothorax taiwanensis Chen, Loh, and Shao, 2008, previously known only from Taiwan. The species differs from all congeners in having the following combination of characters: tail length 45.8%–48.7% of TL; total vertebrae 117–121; jaw teeth stout; vomerine teeth biserial; and iris orange. The present specimen extends the known distribution range of G. taiwanensis northward to Japan and represents the smallest recorded size of the species to date. Comparison with five additional specimens collected from Taiwan in January 2019 and July 2022, including a 707 mm TL individual that extends the known maximum size of the species, revealed coloration variations across body lengths. In addition, the study proposes including the flounced flap of the posterior nostril rim as a diagnostic character of G. taiwanensis, as it readily distinguishes this species from its congeners. The new standard Japanese name “Tankan-utsubo” is proposed for the species.
Zodariellum planum (Zhang and Zhang, 2019) (Araneae: Zodariidae), originally described from Shaanxi, central China, is newly recorded from western Honshu, Japan, on the basis of specimens collected in a vineyard. Conspecificity between males and a previously unknown female is supported by identical partial mitochondrial cytochrome c oxidase subunit I sequences. The present paper provides photographs and illustrations of both sexes, detailed description and diagnosis of the female, DNA barcode data and a distribution map. In Japan, this species is currently known only from a single vineyard population, and its occurrence there may suggest a possible introduction, although this requires further investigation.
