Songpotamon malipoense Shi, Pan & Sun, 2023

Songpotamon malipoense Shi, Pan & Sun, 2023 View in CoL

Figs 11 View Figure 11 , 12 View Figure 12 , 13 View Figure 13 , 14 View Figure 14

Songpotamon malipoense Shi, Pan & Sun, 2023: 29–32, figs 8, 9 D – F, 10 C – D. View in CoL

Material examined.

• 5 males (16.5 × 13.1, 17.0 × 13.8, 18.8 × 14.7, 18.9 × 14.7, 21.0 × 16.2 mm), 7 females (15.0 × 12.3, 15.3 × 12.4, 17.0 × 13.8, 17.8 × 14.3, 18.1 × 14.5, 18.9 × 14.7, 19.0 × 15.5 mm) ( IB - FC-SMx 01), a small stream in Khau Vai , Khau Vai Commune, Meo Vac County, Ha Giang Province, Vietnam, 23°4'55.3920"N, 105°29'34.4639"E, 22 Mar 2024, Do et al. leg GoogleMaps . • 2 males (21.8 × 16.3 mm; 19.4 × 15.3 mm), 1 female (18.8 × 14.6 mm) ( ZRC 2024.0321 View Materials ), same data as above GoogleMaps .

Description.

None (see Shi et al. 2023 for full description).

Distribution.

This species has only been found in karst landscapes between Vietnam and China, namely, Malipo County, Wenshan Prefecture, Yunnan Province, southwest China, and Khau Vai Commune, Meo Vac District, Ha Giang Province, northern Vietnam.

Ecology.

This species was found in mud burrows on the banks of small hill streams (Fig. 11 B View Figure 11 ). Field observations agree well with Shi et al. ’ s (2023) account of their material from Yunnan province, China; the present specimens collected from Ha Giang province, Vietnam, also exhibit a semi-terrestrial lifestyle.

Colouration.

The dorsal surface of the carapace is dark brown, brighter on the ventral surface, and orange on the chelae (Fig. 11 A View Figure 11 ; cf. Shi et al. 2023: fig. 7 A).

Remarks.

The examined specimens agree well with Songpotamon malipoense (see Shi et al. 2023). The specimens collected from Vietnam, like those from China are characterized by the following traits: relatively small adult carapace size ( 15.3–21 mm, n = 14); carapace broader than long, ovate; dorsal surface convex, smooth, pitted, regions not well defined; branchial regions swollen, smooth (Fig. 12 A View Figure 12 ; cf. Shi et al. 2023: fig. 7 A); postorbital and epigastric cristae inconspicuous, not confluent, separated by shallow groove; epigastric cristae weakly developed, oblique, separated by deep inverted Y-shaped groove; postorbital cristae low, weakly rugose (Fig. 12 A View Figure 12 ; cf. Shi et al. 2023: fig. 7 A); external orbital tooth bluntly triangular, outer margin convex, separated from anterolateral margin of carapace by shallow cleft (Fig. 12 A View Figure 12 ; cf. Shi et al. 2023: fig. 7 A); anterolateral margin of carapace convex, cristate, granular; posterolateral margin straight, with multiple weakly oblique striae (Fig. 12 A View Figure 12 ; cf. Shi et al. 2023: fig. 7 A); orbits large; suborbital regions smooth sub-hepatic and pterygostomial regions with small, rounded granules (Fig. 12 B View Figure 12 ; cf. Shi et al. 2023: fig. 7 B); median lobe of epistome posterior margin broadly triangular (Fig. 12 C View Figure 12 ; cf. Shi et al. 2023: fig. 7 B); exopod of third maxilliped without flagellum (Fig. 12 D View Figure 12 ; cf. Shi et al. 2023: fig. 8 C); chelipeds unequal in males (Fig. 12 A View Figure 12 ; cf. Shi et al. 2023: fig. 7 A); thoracic sternites 3, 4 in male fused except for relatively shallow, incomplete groove demarcating suture (Fig. 13 A View Figure 13 ; cf. Shi et al. 2023: fig. 7 C); male pleon narrowly triangular; somite 6 relatively narrow, width to length ratio 2.0 (Fig. 13 A View Figure 13 ; cf. Shi et al. 2023: fig. 8 E); G 1 slender, reaching beyond pleonal locking tubercle up to suture between thoracic sternites 4 and 5 (Fig. 13 B View Figure 13 ; cf. Shi et al. 2023: fig. 8 G); subterminal article relatively slender, gently sinuous, inner margin almost straight; terminal article short, slender, subconical, relatively less strongly bent at about 30 ° angle outwards, about 0.4 times length of subterminal article, with distinct groove for G 2 on ventral side, tip subtruncate, recurved upwards (Fig. 14 View Figure 14 ; cf. Shi et al. 2023: fig. 9 D, E); G 2 longer than G 1; terminal article relatively short; subterminal article about 3.0 times length of terminal article (Fig. 14 View Figure 14 ; cf. Shi et al. 2023: fig. 9 D); female pleon ovate, covering most of thoracic sternum (Fig. 13 C View Figure 13 ; cf. Shi et al. 2023: fig. 8 F); vulvae transversely ovate, closely located to each other, touching suture of thoracic sternites 5 and 6, opened inwards (Fig. 13 D View Figure 13 ; cf. Shi et al. 2023: fig. 8 H).

Geographically, the Chinese and Vietnamese populations are separated by about 70 km (Fig. 15 View Figure 15 ) of lowlands. The area where the Vietnamese specimens were collected is part of a larger karst landscape known as the Dong Van Karst Plateau, which itself is a contiguous extension of the South China karst belt ( Yunnan karst plateau) ( Tran et al. 2022) where the type locality of S. malipoense Shi, Pan & Sun, 2023 , is located.