Songpotamon funingense gen. et sp. nov.

Figs 5, 6, 9A-C, 10A, B

Type material.

Holotype. China • ♂, 27.2 × 21.9 mm; Yunnan Province, Wenshan Prefecture, Funing County, Tianwan Township; 23.20°N, 104.87°E; altitude 880 m asl.; 22 Oct. 2020; Boyang Shi, Ruxiao Wang, and Hongying Sun leg.; GenBank: OR469050; NNU-167462-01.

Paratype. China • ♂, 25.2 × 20.9 mm; same collection data as for holotype; GenBank: OR469051; NNU-167462-02 • ♂, 26.6 × 21.0 mm; same collection data as for holotype; GenBank: OR469057; NNU-167462-03 • ♂, 23.5 × 19.1 mm; same collection data as for holotype; GenBank: OR469058; NNU-167462-04 • ♀, 22.6 × 18.0 mm; same collection data as for holotype; NNU-167462-05 • ♀, 24.6 × 19.7 mm; same collection data as for holotype; NNU-167462-06 • ♂, 22.2 × 17.8 mm; Yunnan Province, Wenshan Prefecture, Funing County, Longbo Township; 23.31°N, 105.46°E; altitude 1611 m asl.; 24 Oct. 2020; Boyang Shi, Ruxiao Wang, and Hongying Sun leg.; GenBank: OR469054; NNU-167533-01 • ♂, 21.5 × 17.7 mm; same collection data as for NNU-167533-01; GenBank: OR469055; NNU-167533-02 • ♀, 20.8 × 16.4 mm; same collection data as for NNU-167533-01; NNU-167533-03.

Diagnosis.

Medium sized (adult carapace width 21-27 mm, n = 9). Carapace broader than long, ovate; dorsal surface convex, smooth, pitted, regions not clear; branchial regions swollen (Fig. 5A). Postorbital and epigastric cristae low, not confluent, separated by weak shallow groove (Fig. 5A); epigastric cristae weakly developed, straight, separated by shallow inverted Y-shaped groove; postorbital cristae low, rugose (Fig. 5A). External orbital angle bluntly triangular, outer margin convex, separated from anterolateral margin of carapace by shallow cleft (Fig. 5A). Anterolateral margin of carapace convex, generally smooth, weakly cristate; posterolateral margins gently converging, smooth (Fig. 5A). Orbits large; supraorbital and infraorbital margins smooth (Fig. 5B); sub-orbital, sub-hepatic and pterygostomial regions smooth or weakly rugose (Fig. 5B, C). Antennular fossae rectangular in anterior view; median lobe of epistome posterior margin low, rounded (Fig. 5B). Exopod of third maxilliped reaching beyond anterolateral corner of ischium, without flagellum (Fig. 6C). Thoracic sternites 3/4 in male fused except for relatively deep, incomplete groove demarcating suture (Figs 5C, 6E, G). Vulvae transversely ovate, closely located to each other, touching suture of sternites 5/6, opened obliquely ~ 45° upwards (Fig. 6H). Male pleon narrowly triangular; somite 6 relatively narrow, width ~ 2.4 × as length (Fig. 5C). G1 slender, almost reaching pleonal locking tubercle in situ (Figs 6G, 9A, B, 10A, B); subterminal segment stout, sinuous, inner margin concave; terminal segment subconical, bent at ~ 45° outwards, relatively short, ~ 0.4 × length of subterminal segment, with distinct groove for G2 on ventral side, tip subtruncate, recurved upwards (Figs 9A, B, 10A, B). G2 longer than G1; terminal segment relatively short; subterminal segment ~ 5 × length of terminal segment (Fig. 9C).

Description.

Medium sized (adult carapace width 21-27 mm, n = 9). Carapace broader than long, ovate; dorsal surface convex transversely, longitudinally, smooth, pitted, regions not clear; branchial regions swollen, smooth (Fig. 5A). Postorbital and epigastric cristae inconspicuous, not confluent, separated by weakly shallow groove (Fig. 5A); epigastric cristae weakly developed, straight, separated by shallow Y-shaped groove; postorbital cristae low, rugose, reaching epibranchial tooth (Fig. 5A). Cervical groove indistinct (Fig. 5A). External orbital angle bluntly triangular, outer margin straight, with shallow cleft demarcating it from epibranchial tooth; epibranchial tooth weakly developed (Fig. 5A). Anterolateral margin convex, smooth, weakly cristate; posterolateral margin gently concave, smooth, converging towards posterior carapace margin (Fig. 5A). Orbits large; supraorbital and infraorbital margins smooth; sub-orbital, sub-hepatic, and pterygostomial regions relatively smooth or weakly rugose (Fig. 5B, C). Antennular fossae rectangular in anterior view; median lobe of epistome posterior margin low, rounded (Fig. 5B). Third maxilliped with rhombus ischium; exopod of third maxilliped reaching beyond anterolateral corner of ischium, without flagellum (Fig. 6C).

Chelipeds unequal (Figs 5A, C, 6A, B). Merus trigonal in cross section; margins crenulated (Fig. 5A, C). Carpus with sharp spine at inner-distal angle (Fig. 5A, C). Major cheliped palm length ~ 1.4 × as height (Fig. 6B). Occlusal margin of fingers with sharp teeth; distinct gape when closed (Fig. 6B).

Ambulatory legs not distinctly elongated, dactyli slender (Figs 5A, C, 6D); second pair longest, last pair shortest (Fig. 5A, C). Outer surface of merus slightly rugose, dorsal margin weakly serrated, without subdistal tooth, length ~ 3.7 × as width (Fig. 6D).

Male thoracic sternum generally smooth, weakly pitted; sternites 1/2 fused to form a triangular structure (Figs 5C, 6E, G); sternites 2/3 demarcated by horizontal groove; sternites 3/4 fused except for relatively deep, incomplete groove demarcating suture (Figs 5C, 6E, G); median longitudinal suture of sternites 7/8 deep (Fig. 6E, G). Vulvae transversely ovate, closely located to each other, touching suture of sternites 5/6, opened obliquely ~ 45° upwards, posteromesial margin with low raised rim (Fig. 6H).

Male pleon narrowly triangular; telson relatively broad, lateral margins slightly convex, width ~ 1.2 × as length (Figs 5C, 6E); somite 6 broadly rectangular, width ~ 2.4 × as length; suture between somites 6/7 sinuous; somites 3-5 trapezoidal, gradually decreasing in width; somite 2 trapezoidal, reaching to bases of coxae of fourth ambulatory legs; thoracic sternite 8 not visible when pleon closed (Figs 5C, 6E). Female pleon ovate, covering most of thoracic sternum (Fig. 6F).

G1 slender, almost reaching pleonal locking tubercle in situ, with terminal and subterminal segments clearly demarcated (Figs 6G, 9A, B, 10A, B); subterminal segment stout, sinuous, distal part prominently narrow, inner margin concave (Figs 9A, B, 10A, B); terminal segment slender, subconical, bent at ~ 45° outwards, relatively short, ~ 0.4 × length of subterminal segment, outer margin slightly convex, inner margin straight, with distinct groove for G2 on ventral side, tip subtruncate, recurved upwards (Figs 9A, B, 10A, B). G2 longer than G1, terminal segment relatively short; subterminal segment ~ 5 × length of terminal segment (Fig. 9C).

Etymology.

The species is named after Funing County, the type locality of the new species in the Yunnan Province of China.

Colour in life.

Carapace and chelipeds are generally bright orange to red with purplish brown ambulatory legs in mature individuals. Generally purplish brown all over with bright orange tips of the chelipeds in smaller individuals.

Habitat.

This new semi-terrestrial species digs and inhabits mud burrows close to small hill streams and seeps.

Remarks.

The new species most closely resembles S. malipoense gen. et sp. nov., in general carapace morphology, especially in possessing the relatively narrower male pleonal somite 6, the recurved tip of the G1 terminal segment, and the distinct and entire groove for the G2 on the ventral side of the G1 terminal segment. Songpotamon funingense gen. et sp. nov., however, can be separated from S. malipoense gen. et sp. nov. by the following characters: 1) anterolateral margins of the carapace generally smooth (Fig. 5A) (vs with small granules; Fig. 7A); epigastric cristae straight in dorsal view and separated from each other by a shallow inverted Y-shaped groove (Fig. 5A) (vs oblique in dorsal view and separated from each other by a relatively deep inverted Y-shaped groove; Fig. 7A); male thoracic sternites 3/4 with relatively deep groove demarcating suture (Figs 5C, 6E, G) (vs relatively shallow; Figs 7C, 8E, G); vulvae opening obliquely ~ 45° upwards (Fig. 6H) (vs opening inwards; Fig. 9H); G1 subterminal segment relatively stouter, with the inner margin concave (Figs 9A, B, 10A, B) (vs relatively slenderer, with the inner margin almost straight; Figs 9D, E, 10C, D); and G1 terminal segment strongly bent at ~ 45° outwards (Figs 9A, B, 10A, B) (vs gently curved at ~ 30° outwards; Figs 9D, E, 10C, D).

The new species is also morphologically similar to S. dixuense comb. nov. in the weakly developed epibranchial tooth, the relatively smooth sub-orbital, sub-hepatic, and pterygostomial regions, and the sinuous subterminal segment of the G1. Songpotamon funingense gen. et sp. nov., however, can be distinguished from S. dixuense comb. nov. by the following characters: antennular fossae subrectangular (Fig. 5B) (vs slit-like); male pleonal somite 6 relatively narrower (Fig. 5C) (vs relatively broader); vulvae opening distinctly oblique ~ 45° upwards (Fig. 6H) (vs opening slightly oblique ~ 30° upwards); G1 subterminal segment relatively stouter (Figs 9A, B, 10A, B) (vs relatively slenderer); and G1 terminal segment relatively strongly bent at ~ 45° outwards (Figs 9A, B, 10A, B) (vs gently curved at ~ 30° outwards) (cf. Naruse et al. 2018: figs 24B, 26, 27).

Geographic distribution.

Songpotamon funingense gen. et sp. nov. is known from Funing County, eastern Wenshan Prefecture, Yunnan Province, southwest China.