• NSMT-Co 1899, An’ei Seamount, Nishi-Shichito Ridge, Japan (29°17.03'N, 138°37.85'E), 770 m depth, October 17, 2021.

Near Iejima Island, Motobu, Okinawa, Japan.

External morphology. Parazoanthidae associated with host hexasterophoran sponge Pararete Ijima, 1927. Approximately 100 truncated cone-shaped cylindrical polyps in preserved specimen. Solitary or colonial polyps rise irregularly from host Pararete sponges (Figs 2B, 3D). The living and preserved polyps dark brown and tentacles brown in coloration. Ectoderm and mesoglea of capitulum encrusted with numerous and comparatively large sizes of sand and silica particles (approximately < 100 µm). No encrustations of sand and silica particles in the ectoderm or mesoglea of scapus (Fig. 3F). Contracted preserved polyps 3.0–10.0 mm in height, 2.8–5.0 mm in diameter. Capitulary ridges discernible when contracted, 15–16 in number, and 30–32 tentacles (Fig. 3E).

Northwestern Pacific Ocean: Churabanakuroshioae was originally reported from the Ryukyu Archipelago, Japan at depths of 520–650 m (Kise et al. 2022). The findings in this study reveal that this species is also distributed at the An’ei Seamount, Nishi-Shichito Ridge, Japan at a depth of 770 m. Churabanakuroshioae was found on the summit of An’ei Seamount on glass sponge Pararete sp. attached to rocky substrate.

Pararete sp.

The polyp coloration of Churabanakuroshioae is cream-pink or beige with cream or whitish transparent tentacles in the original description, while the specimen of C.kuroshioae collected from An’ei Seamount has dark brown polyps with brown tentacles. As well, the polyp sizes of the specimen examined in this study were relatively larger than that of the original description (3.0–4.0 mm in height, 2.8–4.0 mm in diameter) by Kise et al. (2022). Based on the results of molecular phylogenetic analyses, the differences in coloration and polyp sizes found in this study are considered intraspecific variation, although detailed molecular analyses in the future may warrant reconsideration of this.