Two new species of freshwater crab of the genus Aparapotamon Dai & Chen, 1985 (Crustacea, Brachyura, Potamidae) from Yunnan, China Author Tan, Qi-Hong Research Laboratory of Freshwater Crustacean Decapoda & Paragonimus, School of Basic Medical Sciences, Nanchang University, 461 Bayi Avenue, Nanchang City, Jiangxi Province 330006, China Author Zhou, Xiao-Juan Research Laboratory of Freshwater Crustacean Decapoda & Paragonimus, School of Basic Medical Sciences, Nanchang University, 461 Bayi Avenue, Nanchang City, Jiangxi Province 330006, China Author Zou, Jie-Xin https://orcid.org/0000-0002-5549-2167 Research Laboratory of Freshwater Crustacean Decapoda & Paragonimus, School of Basic Medical Sciences, Nanchang University, 461 Bayi Avenue, Nanchang City, Jiangxi Province 330006, China & Key laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Nanchang University, 1299 Xuefu Avenue, Nanchang City, Jiangxi Province 330031, China jxzou@ncu.edu.cn text ZooKeys 2021 2021-08-20 1056 149 171 http://dx.doi.org/10.3897/zookeys.1056.63755 journal article http://dx.doi.org/10.3897/zookeys.1056.63755 1313-2970-1056-149 569F6C2B8F214048B8D885525264217C CBBA6D635B8A55E294237370CD1936F3 Aparapotamon huizeense sp. nov. Figures 5 , 6 , 7 , 8 Material examined. Holotype : NCU MCP 179801, 1♂ (25.9 x 21.2 mm ), China , Yunnan Province , Qujing City , Huize County , Nagu Town , Zebu Village , 26°30'41"N , 103°10'25"E , alt. 1954 m , 25 Aug 2011 , Yue Huang leg. Paratypes : NCU MCP 179802, 1♂ (26.9 x 21.9 mm ) and NCU MCP 179803-179808, 6♀♀ (31.0 x 24.8 mm , 30.7 x 23.6 mm , 27.3 x 21.5 mm , 23.5 x 18.4 mm , 25.5 x 20.5 mm , 29.8 x 22.6 mm ), same data as holotype . Diagnosis. Carapace trapezoidal, dorsal surface slightly convex, regions defined. External orbital angle round, separated from anterolateral margin, postorbital cristae convex, postfrontal lobe prominent. Cervical groove shallow, H-shaped groove distinct, especially in female specimen. Epibranchial tooth distinct, especially in female specimen. Third maxilliped exopod without flagellum. Ambulatory legs slender. Male pleon broad triangular, telson triangular, apex rounded. Vulva ovate, covering anterior half of sternite 6, with the posterior margin distinctly convex. G1 very slender, dorsal lobe well developed, exceeding suture 4/5 in situ, G2 basal segment ovate, tip of terminal segment round. Description. Carapace width 1.25 x length (n = 8), regions distinctly defined; dorsal surface slightly convex, anterolateral and frontal region covered with conspicuous round granules (Fig. 5A, B ). External orbital angle triangular, round, separated from anterolateral margin by deep notch (Figs 5A-C , 7A ). Postorbital cristae convex, not continuous to epibranchial tooth; postfrontal lobe prominent, separated medially by a Y-shaped groove extending to the frontal region (Figs 5A, B , 7A ). Cervical groove shallow; H-shaped gastro-cardiac groove distinct, especially in female specimen (Figs 5A, B , 7A ). Epibranchial tooth sharp, distinct, especially in female specimen; anterolateral margin cristae distinct, curved inwards posteriorly, lined with approximately 10-13 ambiguous granules; posterolateral surface smooth, with some inconspicuous oblique striae, converging towards posterior carapace margin (Figs 5A, B , 7A ). Orbits and eyes medium-size; supraorbital margin ridged, infraorbital margins cristate, minutely granulated (Fig. 5C ). Sub-orbital smooth, pterygostomial and sub-hepatic regions covered with sparse round granules (Fig. 5C ). Epistome posterior margin median lobe broad triangular, lateral margin with small projection (Fig. 5C ). Figure 5. Aparapotamon huizeense sp. nov. Holotype male (25.9 x 21.2 mm) (NCU MCP 179801) A overall habitus B dorsal view of carapace C frontal view of cephalothorax. Scale bars: 1 cm. Third maxilliped exopod without flagellum, claviform, reaching proximal 1/3 of merus lateral margin (Figs 5C , 6B ). Ischium about 1.4 times as long as broad, rectangular, longitudinal median sulcus indistinct (Fig. 6B ). Merus about 1.3 times as broad as long, subquadrate, median slightly depressed (Figs 5C , 6B ). Chelipeds unequal in both adult male and female, palm of larger cheliped length 1.4 x height (n = 8); dactylus 0.6 x palm length (n = 8); slightly shorter than pollex (Figs 5A , 6A ). Merus outer surface punctate; carpus surface covered with several prominent granules and sharp spine at inner-distal angle (Figs 5A , 7A ). Occlusal margins of fingers of adult male with numerous round blunt teeth, with narrow gap when fingers closed (Fig. 6A ). Ambulatory legs slender; second ambulatory legs longest; fourth ambulatory leg propodus 1.9 x as long as broad (n = 8), shorter than dactylus, which accompanied with several thorn-like setae (Figs 5A , 6D ). Figure 6. Aparapotamon huizeense sp. nov. Holotype male (25.9 x 21.2 mm) (NCU MCP 179801) A outer view of right cheliped B left third maxilliped C ventral view of pleon D right fourth ambulatory leg E ventral view of anterior thoracic sternum and telson F ventral view of sterno-pleonal cavity with right G1 in situ; arrow indicates pleonal locking tubercle. Scale bars: 2 mm ( B ); 5 mm ( A, C-F ). 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. 6C, E ). Male sterno-pleonal cavity deep; median longitudinal groove between sternites 7, 8 long; male pleonal locking tubercle barely visible, almost middle of sternite 5 (Fig. 6F , arrow). Male pleon broad triangular (Fig. 6C ); telson triangular, apex rounded, width 1.4 x length in males (n = 2), 2.5 x in females (n = 6); somite 6 trapezoidal, width 2.3 x length in males (n = 2), 3.0 x in females (n = 6) (Figs 6C , 7B ). Vulva medium-size, ovate, superior margin reaching suture 5/6 in situ, opening inward, posterior margin distinctly convex, the sternal vulvar cover broadly triangular and relatively low (Fig. 7C ). Figure 7. Aparapotamon huizeense sp. nov. Paratype female (31.0 x 24.8 mm) (NCU MCP 179803) A overall habitus B ventral view of pleon C vulvae. Scale bars: 10 mm. G1 very slender; terminal segment claviform, slightly bent distally, inner margin arc-shaped, outer margin straightly, dorsal lobe well developed and gonopod pore located in it (Fig. 8A-D ); exceeding suture4/5 in situ (Fig. 6F ); clear boundary between terminal segment and subterminal segment, the latter length about 0.9 x length of terminal segment (Fig. 8A, C ). G2 basal segment ovate, about 1.9 x length of terminal segment, tip of terminal segment round (Fig. 8E ). Figure 8. Aparapotamon huizeense sp. nov. Holotype male (25.9 x 21.2 mm) (NCU MCP 179801) A ventral view of left G1 B ventral view of terminal segment of left G1 C dorsal view of left G1 D dorsal view of terminal segment of left G1 E ventral view of left G2. Scale bars: 1 mm. Etymology. The species is named after the type locality, Huize County, Qujing City, Yunnan Province. Distribution. The new species is presently known only from the type locality presently, Huize County, Qujing City, Yunnan Province. Remarks. Aparapotamon huizeense sp. nov. closely resembles A. grahami in the general carapace morphology and G1 structure. However, A. huizeense sp. nov. can be distinguished from A. grahami by the following characters: G1 exceeding suture 4/5 in situ (Fig. 6F ) [vs. reaching pleonal locking tubercle but not reaching suture 4/5 in situ ( Dai 1999 : fig. 187)]; and the G1 is very slender, terminal segment slightly bent distally, dorsal lobe well developed (Fig. 9B ) [vs. slender, terminal segment without bending (Fig. 9J ), dorsal lobe variably developed]. A. huizeense sp. nov. is also similar to A. huiliense . But, in A. huiliense , G1 extends to pleonal locking tubercle but not exceeding suture 4/5 in situ ( Dai 1999 : fig. 189) and its dorsal lobe roundly developed (Fig. 9K ). For detailed differences between this new species and congeners, see Table 2 . Figure 9. Left G1s. A Aparapotamon binchuanense sp. nov. NCU MCP 170701 B Aparapotamon huizeense sp. nov. NCU MCP 179801 C Aparapotamon inflomanum (Dai & Chen, 1985), IZCAS CB 05096 D Aparapotamon molarum (Dai & Chen, 1985), CAS CB 05094 E Aparapotamon emineoforaminum (Dai & Chen, 1985), CAS CB 05090 F Aparapotamon tholosum (Dai & Chen, 1985), CAS CB 05092 G Aparapotamon protinum (Dai & Chen, 1985), CAS CB 05093 H Aparapotamon arcuatum (Dai & Chen, 1985), CAS CB 05091 I Aparapotamon muliense (Dai & Chen, 1990), CAS CB 05088 J Aparapotamon grahami (Rathbun, 1929), CAS CB 00142 K Aparapotamon huiliense (Dai & Chen, 1985), CAS CB 05089 L Aparapotamon similium (Dai & Chen, 1985), CAS CB 05095 M Aparapotamon gracilipedum (Chen & Chang, 1982), CAS CB 05148. Table 2. Morphological differences among species of Aparapotamon .

Species/characters	Epibranchial tooth	Pterygostomial and sub-hepatic regions	Sub-orbital region	G1 in situ	Terminal segment of G1	Vulva
A. binchuanense sp. nov.	Blunt (Fig. 1A )	Densely covered with round granules (Fig. 1C )	Sparely covered with round granules (Fig. 1C )	Exceeding pleonal locking tubercle but not suture 4/5 (Fig. 2F )	Slender, distal end tapering, distinctly bent (Fig. 9A )	Ovate, posterior margin not convex (Fig. 3C )
A. huizeense sp. nov.	Sharp (Fig. 5A )	Sparely covered with round granules (Fig. 5C )	Smooth (Fig. 5C )	Exceeding suture 4/5 (Fig. 6F )	Very slender, distal end slightly bent, dorsal lobe well developed inward (Fig. 9B )	Ovate, posterior margin distinctly convex (Fig. 7C )
A. inflomanum (cf. Dai 1999 : fig. 196)	Blunt	Smooth	Smooth	Reaching suture 4/5	Slender, distal end disc-shaped (Fig. 9C )	Ovate, posterior margin not convex
A. molarum (cf. Dai 1999 : fig. 195)	Blunt	Smooth	Smooth	Exceeding suture 4/5	Slender, distal end disc-shaped (Fig. 9D )	Transversely ovate, posterior margin not convex
A. emineoforaminum (cf. Dai 1999 : fig. 197)	Blunt	Densely covered with round granules	Smooth	Exceeding suture 4/5	Very slender, tapering distally (Fig. 9E )	Ovate, posterior margin distinctly convex
A. tholosum (cf. Dai 1999 : fig. 194)	Sharp	Densely covered with round granules	Smooth	Exceeding pleonal locking tubercle but not suture 4/5	Slender, dorsal lobe well developed upwards (Fig. 9F )	Transversely ovate, posterior margin distinctly convex
A. protinum (cf. Dai 1999 : fig. 193)	Sharp	Densely covered with round granules	Smooth	Exceeding pleonal locking tubercle but not suture 4/5	Slender, dorsal lobe slightly developed upwards (Fig. 9G )	Transversely ovate, posterior margin arching to form semicircular structure
A. arcuatum (cf. Dai 1999 : fig. 191)	Blunt	Sparely covered with round granules	Smooth	Exceeding pleonal locking tubercle but not suture 4/5	Slender, arc-shaped, dorsal lobe slightly developed upwards (Fig. 9H )	Transversely ovate, posterior margin not convex
A. muliense (cf. Dai 1999 : fig. 192)	Blunt	Sparely covered with round granules	Smooth	Exceeding pleonal locking tubercle but not suture 4/5	Slender, arc-shaped, dorsal lobe well developed upwards (Fig. 9I )	Transversely ovate, posterior margin distinctly convex
A. grahami (cf. Dai 1999 : fig. 187)	Sharp	Sparely covered with round granules	Smooth	Reaching pleonal locking tubercle	Slender, dorsal lobe variably developed inwards (Fig. 9J )	Ovate, posterior margin slightly convex
A. huiliense (cf. Dai 1999 : fig. 189)	Sharp	Sparely covered with round granules	Smooth	Exceeding pleonal locking tubercle but not suture 4/5	Slender, dorsal lobe roundly developed (Fig. 9K )	Transversely ovate, posterior margin slightly convex
A. similium (cf. Dai 1999 : fig. 188)	Blunt	Densely covered with round granules	Sparely covered with round granules	Exceeding pleonal locking tubercle but not suture 4/5	Slender, dorsal lobe slightly developed inwards, tapering distally (Fig. 9L )	Transversely ovate, posterior margin distinctly convex
A. gracilipedum (cf. Dai 1999 : fig. 190)	Sharp	Densely covered with round granules	Sparely covered with round granules	Exceeding pleonal locking tubercle but not suture 4/5	Slender, dorsal lobe slightly developed inwards, distal end blunt (Fig. 9M )	Ovate, posterior margin slightly convex