Tetralia nigrolineata Serène & Pham, 1957

(Fig. 4C–D, 6E, F)

Tetralia glaberrima f. nigrolineata Serène & Pham, 1957:120 .

Tetralia nigrolineata —Galil 1988: 63, figs. 1c, 2e, f.— Castro 1997a: 68, pl. 1D; 1999a: 41; 1999b: 102; 2009: 277.— Castro et al. 2004: 25 (list).—Machida 2005: 24, fig. 4 (Tosa shimizu).—Castro & Titelius 2008: 321— Ng et al. 2008: 184 (list).— Limviriyakul 2016: 4, fig. 4k (Taiwan Island).— Maenosono 2017: 42, fig. 8C, D (Ryukyus).

Tetralia glaberrima f. obscura Patton, 1966: 287.

Tetralia glaberrima obscura Serène, 1984: 283, pl. 40E.

Not Tetralia nigrolineata — Castro 2009: 277, fig. 2F [= Te. glaberrima Herbst, 1790]— Poupin 2018: 37, fig. 12E [ Tetralia? nigrolineata = Te. glaberrima Herbst, 1790].

Material examined. Hainan Island: Hou Hai, coll. Yuli Sun, 5 May 2023, 1 female (7.21 × 6.10 mm), VX20230501; 3 m, coll. Yuli Sun, 29 November 2022, 1 male (11.35 × 10.59 mm), 1 female (13.77 × 12.01 mm), XY1102. Xiaodong Hai, 2–3 m, coll. Lecheng Qu, 5 December 2021, 1 female (11.21 × 10.07 mm), SY24. Lu hui tou, 3 m, coll. Sirenko, 19 November 2016 , 1 pre-adult (3.27 × 2.96 mm), SY94.

Geographical distribution. Across Indo-West Pacific region except the Hawaiian Islands (Castro et al. 2004).

Remarks. Tetralia nigrolineata is the largest species of the genus recorded in the South China Sea. A unique specimen (Fig. 6E, VX20230501) that was collected possess pereiopods that are all white in color. We attempted to explore whether this coloration is of phylogenetic interest, and so we aligned its COI sequence with an individual of normal coloration (SY24) (Fig. 6F, XY1102). The result, however, suggests that they are conspecific. The phylogenetic tree (Fig. 11) and genetic distance (Table 3) indicate minimal genetic divergence between the individual with a typical brown pattern (Fig. 6F, XY1102; Fig. 11, SY24) when compared to the specimen with white pereiopods (Fig. 6E; Fig. 11, VX20230501).