Aparapotamon binchuanense, Tan & Zhou & Zou, 2021

Tan, Qi-Hong, Zhou, Xiao-Juan & Zou, Jie-Xin, 2021, Two new species of freshwater crab of the genus Aparapotamon Dai & Chen, 1985 (Crustacea, Brachyura, Potamidae) from Yunnan, China, ZooKeys 1056, pp. 149-171 : 149

publication ID	https://dx.doi.org/10.3897/zookeys.1056.63755
publication LSID	lsid:zoobank.org:pub:569F6C2B-8F21-4048-B8D8-85525264217C
persistent identifier	https://treatment.plazi.org/id/05703D3E-5F19-4587-9494-C1AFB7DF8327
taxon LSID	lsid:zoobank.org:act:05703D3E-5F19-4587-9494-C1AFB7DF8327
treatment provided by	ZooKeys by Pensoft
scientific name	Aparapotamon binchuanense
status	sp. nov.

Treatment

Aparapotamon binchuanense View in CoL sp. nov.

Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Material examined.

Holotype: NCU MCP 170701, 1♂ (17.1 × 13.6 mm), China, Yunnan Province, Dali Bai Autonomous Prefecture, Binchuan County, Lawu Town , 25°53'34"N, 100°55'30"E, alt. 1658 m, 10 Aug 2010, Han Dai leg. GoogleMaps Paratypes: NCU MCP 170702, NCU MCP 170704, NCU MCP 170705, 3♂♂ (15.7 × 13.1 mm, 15.6 × 12.5 mm, 14.3 × 11.6 mm) and NCU MCP 170703, NCU MCP 170706, NCU MCP 170707, 3♀♀ (21.4 × 17.1 mm, 20.8 × 16.8 mm, 19.0 × 15.6 mm), same data as holotype GoogleMaps .

Diagnosis.

Carapace trapezoidal, regions defined. External orbital angle triangular, postorbital cristae convex, postfrontal lobe prominent. Cervical groove indistinct, H-shaped groove conspicuous. Epibranchial tooth blunt, anterolateral margin lined with numerous granules. Third maxilliped exopod without flagellum. Adult male and female chelipeds slightly unequal. Ambulatory legs relatively slender. Male sterno-pleonal cavity deep, median longitudinal groove between sternites 7/8 long. Male pleon narrow triangular, telson triangular. Vulva small, ovate, located close to each other at anterior part of sternites 6, posterior margin not convex. G1 slender, distal end tapering, distinctly bent. G2 basal segment ovate, tip of terminal segment laterally flattened.

Description.

Carapace width 1.25 × length (n = 7), regions defined; dorsal surface slightly convex (Figs 1A, B View Figure 1 , 3A View Figure 3 ). External orbital angle triangular, separated from anterolateral margin by conspicuous notch (Figs 1A, C View Figure 1 , 3A View Figure 3 ). Postorbital cristae gently convex, continuous to epibranchial tooth; postfrontal lobe prominent, separated medially by inverted Y-shaped groove (Figs 1A, B View Figure 1 , 3A View Figure 3 ). Cervical groove indistinct; H-shaped gastro-cardiac groove distinct (Figs 1A, B View Figure 1 , 3A View Figure 3 ). Epibranchial tooth blunt, rounded; anterolateral margin cristae, curved inward posteriorly, lined with approximately 15-17 fused granules; posterolateral surface slightly smooth, with some inconspicuous oblique striae, converging towards posterior carapace margin (Figs 1A, B View Figure 1 , 3A View Figure 3 ). Orbits and eyes large; supraorbital margin ridged, infraorbital margin cristate, minutely granulated (Fig. 1C View Figure 1 ). Pterygostomial and sub-hepatic regions covered with dense round granules, sub-orbital region with sparse granules (Fig. 1C View Figure 1 ). Epistome posterior margin median lobe equilateral triangular, lateral margin with small projection (Fig. 1C View Figure 1 ).

Third maxilliped exopod without flagellum, claviform, reaching proximal 1/3 of merus lateral margin (Figs 1C View Figure 1 , 2B, E View Figure 2 ). Ischium about 1.3 times as long as broad, rectangular, with distinct longitudinal median sulcus (Fig. 2B, E View Figure 2 ). Merus about 1.4 times as broad as long, subquadrate, median slightly depressed (Figs 1C View Figure 1 , 2B, E View Figure 2 ).

Chelipeds slightly unequal in both adult male and female, right cheliped larger (Fig. 2A View Figure 2 ). Palm of larger cheliped length 1.4 × height (n = 7); dactylus 0.7 × palm length (n = 7); dactylus as long as pollex (Figs 1A View Figure 1 , 2A View Figure 2 , 3A View Figure 3 ). Merus outer surface punctate; carpus surface covered with several prominent granules and sharp spine at inner-distal angle (Figs 1A View Figure 1 , 3A View Figure 3 ). Occlusal margins of fingers of adult male with numerous sparse round blunt teeth, with narrow gap when fingers closed (Fig. 2A View Figure 2 ). Ambulatory legs very slender; second ambulatory legs longest; fourth ambulatory leg propodus 2.1 × as long as broad (n = 7), shorter than dactylus, which accompanied with several thorn-like spines (n = 7) (Figs 1A View Figure 1 , 2D View Figure 2 ).

Male thoracic sternum punctate, formed by tidy depression; sternites 1-4 broad, sternites 1/2 completely continuous; suture 2/3 complete, transverse; suture 3/4 visible, mesially reaching distolateral part of sterno-pleonal cavity (Fig. 2E View Figure 2 ). Male sterno-pleonal cavity deep; median longitudinal groove between sternites 7/8 long; male pleonal locking tubercle inconspicuous, positioned medially on sternite 5 (Fig. 2F View Figure 2 , arrow). Male pleon narrow triangular (Fig. 2C View Figure 2 ); telson triangular, apex rounded, width 1.3 × length in males (n = 4), 1.8 × in females (n = 3); somite 6 trapezoidal, width 2.5 × length in males (n = 4), 3.3 × in females (n = 3) (Figs 2C View Figure 2 , 3B View Figure 3 ). Vulvae small, ovate, located close to each other at anterior part of sternites 6, pushing mesial portions of sutures 5/6 forward, deeper laterally, posterior margin not convex, the sternal vulvar cover triangular, positioned mesially (Fig. 3C View Figure 3 ).

G1 slender; terminal segment claviform, distal end tapering, distinctly bent, inner margin arc-shaped, outer margin straight, dorsal lobe barely visible in ventral view (Fig. 4A-D View Figure 4 ); tip reaching beyond pleonal locking tubercle but not exceed sternites 4/5 in situ (Fig. 2F View Figure 2 ); clear boundary between terminal segment and subterminal segment, latter length about 0.7 × length of terminal segment (Fig. 4A, C View Figure 4 ). G2 basal segment ovate, about 1.5 × length of terminal segment, tip of terminal segment flat rather than sharp (Fig. 4E View Figure 4 ).

Etymology.

The species is named after the type locality, Binchuan County, Dali Bai Autonomous Prefecture, Yunnan Province.

Distribution.

The new species is presently known only from the type locality, Binchuan County, Dali Bai Autonomous Prefecture, Yunnan Province.

Remarks.

Aparapotamon binchuanense sp. nov. closely resembles congeners in general carapace morphology. However, A. binchuanense sp. nov. can be distinguished from other species by the terminal segment of G1, which is claviform, with distal end tapering and distinctly bent (Fig. 9A View Figure 9 ) [vs. terminal segment of G1 disc-shaped, straight in A. inflomanum and A. molarum (Fig. 9C, D View Figure 9 ), terminal segment of G1 of A. emineoforaminum tapering distally but not bent (Fig. 9E View Figure 9 ), terminal segment of G1 arc-shaped in A. arcuatum and A. muliense (Fig. 9H, I View Figure 9 ), and terminal segment of G1 of A. tholosum , A. protinum , A. grahami , A. huiliense , A. similium and A. gracilipedum claviform, not bent (Fig. 9F, G, J-M View Figure 9 )]. In addition, in A. binchuanense sp. nov., the pterygostomial region is densely covered with round granules, while in the sub-orbital region the granules are sparse.

(Fig. 1C View Figure 1 ). This character can also distinguish A. binchuanense sp. nov. from congeners. For detailed differences between this new species and congeners, see Table 2 View Table 2 .