Beuroisia major ( Sakai, 1978 )

Beuroisia major ( Sakai, 1978) View in CoL

( Figure 10 View FIGURE 10 )

Neopilumnoplax major Sakai, 1978: 31 View in CoL , figs. 16–17, pl. 2 fig. A.

Neopliumnoplax [sic] major — Sakai 1978: 8.

Beuroisia major View in CoL — Guinot & Richer de Forges 1981a: pl. 4 figs. 4, 5, pl. 5 figs. 2, 3.— Guinot & Richer de Forges 1981b: 244, figs. 5A, B, 7H.— Ikeda 1998: 142, unnumbered figures.— Takeda & Suyama 2019: 56, figs. 1D, 8.

Beuroisia majora — Takeda & Komatsu 2023: 173 (list).

Material examined. JAMSTEC 106916, 1 female (42.2 × 58.3 mm), R / V Kaimei , KM20-10 C cruise, KM-ROV dive #135, Nikko Seamount, northern Central Mariana Ridge, 23°05.01'N, 142°19.48'E, 365 m, rock, suction sampler, 11 December 2020 GoogleMaps .

Genetic data. 16S rRNA gene: LC856567 View Materials (557 bp) .

Colouration in life. Body and pereopods all orange-red, fingers of chelipeds black ( Fig. 10 View FIGURE 10 ).

Remarks. The present female specimen agrees well with the previous accounts of B. major by Sakai (1978), Guinot & Richer de Forges (1981b), Ikeda (1998) and Takeda & Suyama (2019). Takeda & Komatsu (2023) used “ majora ” as name of the species, but no justification was provided. It is possible to be an accidental misspelling captured by auto-correct function in MS Word software.

Here, we provide a partial sequence of the 16S rRNA gene of Beuroisia major for the first time. In the BLAST search, the 16S rRNA gene sequence had 90% similarity to sequences of the progeryonid Rhadinoplax microphthalmus ( Guinot & Richer de Forges, 1981b) (OR448056: Wolfe et al. 2024), the parthenopid Parthenope longimanus ( Linnaeus, 1758) ( MZ424935 View Materials : Muñoz et al. 2021) and the hypothalassiid Hypothalassia armata (De Haan, 1835) (OR448060: Wolfe et al. 2024). No genetic data is available for other species of Mathildellidae at present.

Distribution. Previous records of this species are from the Northwestern Pacific localities: Kinmei Seamount in the Emperor Seamount Chain, Sagami Bay ( Japan), and Okino-torishima Island, Kyushu-Palau Ridge; 180–600 m deep ( Sakai 1978; Ikeda 1998; Takeda & Suyama 2019).