Chinapotamon cf. pusillum ( Song, 1984 )

Chinapotamon cf. pusillum ( Song, 1984) View in CoL

( Figs. 4–5 View FIGURE 4 View FIGURE 5 , 10B View FIGURE 10 )

Tiwaripotamon pusillum Song, 1984: 143–145 View in CoL , figs. 1–9.

Chinapotamon pusillum View in CoL — Dai & Naiyanetr 1994: 63, fig. 10.— Dai 1999: 91–92, fig. 42, pl. 4.4.— Ng et al., 2008: 161.— Ng, 2017: 7.— Chu et al., 2018: 2.— Zou et al. 2018:2, 10–13.

Material examined. 5 males (12.2 × 11.4 mm, 14.2 × 12.3 mm, 14.8 × 13.9 mm, 15.9 × 14.2 mm, 15.9 × 12.9 mm), 5 females (17.3 × 14.0 mm, 18.5 × 15.6 mm, 20.0 × 16.5 mm, 21.0 × 18.0 mm), IEBR-FC-CPx01, Vietnam, Quang Ninh, Binh Lieu, Dong Van, Song Mooc village , N 21°33’11.5” E 107°34’21.2”, a creek flows into rice a field canal, coll. Do VT., 22 March 2023 GoogleMaps .

Remarks. Examined specimens have characters agreeing well with Chinapotamon pusillum ( Song, 1984) . The species are characterized by: the small body size; the carapace dorsal surface being gently convex; the relatively distinct epigastric and postfrontal cristae ( Fig. 4A, B View FIGURE 4 ); the quadrate ischium of third maxilliped, about 1.5 times longer than broad ( Fig. 4C View FIGURE 4 ); there is almost no gap when the fingers of male major chela closes ( Fig. 4D View FIGURE 4 ); the broadly rectangular male pleonal somite sixth, width to length ratio is 1.9 ( Fig. 5A View FIGURE 5 ); the G1 is relatively slender, terminal segment directed upwards ( Fig. 5B View FIGURE 5 ). Our specimens displayed some differences when compared to the descriptions of this species in Dai & Naiyanetr (1994), Dai (1999), Ng (2017) and Zou et al. (2018): the anterolateral crista is low ( Figs. 4A, B View FIGURE 4 ) (vs. the anterolateral crista is distinct; cf. Dai, 1999: pl. IV, fig. 4; Ng, 2017: table 1; Zou et al., 2018: table 2); G1 does not exceed the suture of sternites 4 and 5 ( Fig 5A View FIGURE 5 ) (vs. G1 exceeds the suture of sternites 4 and 5; cf. Dai & Naiyanetr 1994: Fig. 10.4 View FIGURE 10 ; Dai 1999: Fig. 42.4). The live colouration is overall brown in the specimens collected from Vietnam ( Fig. 10B View FIGURE 10 ).