Cherusius triunguiculatus (Borradaile, 1902)

(Fig. 1A)

Pseudozius triunguiculatus Borradaile, 1902: 243, fig. 44.—Rathbun 1906: 861.—Balss 1938: 64.

Cherusius triunguiculatus .— Boyko 2017: 488, fig. 1A (the Easter Islands).

Jonesius triunguiculatus . — Galil & Takeda 1986: 165, figs. 1–4.— Castro 1999a: 32 (Indonesia).— Castro et al. 2004: 20, pl. 1B (New Caledonia).— Liu et al. 2008: 791 (list) (Xisha Islands).— Castro 2011: 78 (Hawaiian Islands).

Maldivia triunguiculata Guinot, 1964: 102, pl. 4, figs. 1–3, pl. 12, fig. 2; 1967, 271.— Serène 1984: 297, fig. 206–207.

Jonesius minuta Sankarankutty, 1962: 141, figs. 42–45.

Maldivia gardineri Rathbun, 1911: 233, pl. 19, figs. 5, 6.

Maldivia galapagensis Garth, 1939: 22, pl. 8, figs. 1–6.

Material examined. Xisha Islands: The Seven Connected Islets, 112°16.2’E 16°58.0’N, 10 m, coll. Shaobo Ma, Yuli Sun, Ziming Yuan, 19 May 2022, 1 male (3.18 × 2.75 mm), 1 pre-adult (1.74 × 1.57 mm), XS-QL-2022-1013, in Faviidae; 1 male (2.94 × 2.57 mm), XS-QL-2022-1066, in Leptastrea sp. ( Faviidae).

Geographical distribution. Across Indo-West Pacific and Tropical Eastern Pacific regions (Castro 2011).

Remarks. The preoccupied Jonesius Sankarankutty, 1962, was replaced by Cherusius (Low & Ng 2012) . Cherusius triunguiculatus is rarely reported (Castro 2015), this is the first live colouration of this species from Chinese waters. A male specimen collected from a Leptastrea sp. ( Faviidae) colony has a dark brown patch on the lower middle part of the mobile finger of the chelipeds (Fig. 1A, XS-QL-2022-1066). The other two specimens without the dark brown patch were collected from a Faviidae .