Sinolapotamon cirratum, Lu & Zhang & Zou, 2023

Lu, Yuan-Biao, Zhang, Yi-Xuan & Zou, Jie-Xin, 2023, The systematic position of Cryptopotamon anacoluthon (Kemp, 1918), with the description of a new species of Sinolapotamon Tai & Sung, 1975 (Crustacea, Decapoda, Brachyura, Potamidae) from southern China, ZooKeys 1166, pp. 155-173 : 155

publication ID	https://dx.doi.org/10.3897/zookeys.1166.101737
publication LSID	lsid:zoobank.org:pub:7BCF174D-E335-49B2-9799-4F7E99D01FB7
persistent identifier	https://treatment.plazi.org/id/25AEC22F-BAAA-4DF5-8580-8334F8DBB9EC
taxon LSID	lsid:zoobank.org:act:25AEC22F-BAAA-4DF5-8580-8334F8DBB9EC
treatment provided by	ZooKeys by Pensoft
scientific name	Sinolapotamon cirratum
status	sp. nov.

Treatment

Sinolapotamon cirratum sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7A View Figure 7 , 8 View Figure 8

Type material.

Holotype: China • ♂ (17.90 × 15.50 mm); Guangxi Zhuang Autonomous Region, Yulin City, Rong County, Duqiaoshan Forest Park; 22.8019°N, 110.6098°E; October 2022; Yi-Xuan Zhang leg.; NCU MCP 434201. Paratypes: CHINA • 1 ♀ (17.42 × 15.45 mm); same collection data as for holotype; NCU MCP 433901 • 1 ♀ (23.74 × 20.30 mm); same collection data as for holotype; NCU MCP 433902 • 4 ♂♂ (22.54 × 19.55 mm, 22.92 × 19.80 mm, 23.05 × 20.24 mm, 18.00 × 16.02 mm); same collection data as for holotype; NCU MCP 433903-433906.

Other material.

China • 7 ♂♂ (21.96 × 19.12 mm, 13.36 × 11.93 mm, 15.76 × 13.18 mm, 17.34 × 14.99 mm, 17.26 × 14.94 mm, 17.93 × 14.91 mm, 20.73 × 17.62 mm); same collection data as for holotype; NCU MCP 434202-434208 • 8 ♂♂ (14.99 × 12.90 mm, 9.48 × 8.65 mm, 9.61 × 8.54 mm, 9.81 × 8.91 mm, 8.71 × 7.53 mm, 8.82 × 7.77 mm, 9.74 × 7.38 mm, 10.42 × 8.79 mm); Guangxi Zhuang Autonomous Region, Yulin City , Rong County, Silaochong , small stream; 22.8263°N, 110.6065°E; November 2018; Jie-Xin Zou et al. leg.; NCU MCP 416001-416008 GoogleMaps .

Diagnosis.

Carapace subquadrate, regions indistinct; dorsal surface gently convex, anterolateral region weakly rugose. Cervical groove shallow and wide; H-shaped groove shallow (Figs 3A View Figure 3 , 5A View Figure 5 ). Epigastric cristae distinct, separated from postorbital cristae by narrow gap; epibranchial region slightly depressed; mesogastric region gently convex. External orbital angle triangular, distinctly separated from anterolateral margin by wide notch. Anterolateral margin of carapace distinctly cristate, lined with approximately 20 granules (Figs 3A View Figure 3 , 5A View Figure 5 ). Maxilliped 3 exopod reaching nearly 1/2 of merus length, with long flagellum, slightly longer than width of merus (Fig. 4B View Figure 4 ). Chelipeds (pereiopod 1) strongly unequal in males, subequal in females (Figs 3A View Figure 3 , 4A View Figure 4 , 5A View Figure 5 ). G1 slender, subterminal segment about 1.7 times as long as terminal segment; 2 lobes of terminal segment strongly unequal, dorsal lobe longitudinally extended, oval shaped, ventral lobe blunt, reaching 1/2 of terminal segment (Figs 6A-D View Figure 6 , 7A View Figure 7 ). Female vulvae ovate, medium-sized, occupying anterior 2/3 length of sternite 6 (Fig. 5B View Figure 5 ).

Description.

Carapace subquadrate, nearly 1.2 times as wide as long; surface generally smooth, regions indistinct; dorsal surface slightly convex, with tiny pits, anterolateral region weakly rugose. Cervical groove shallow and wide; H-shaped groove shallow. Front gently deflexed; frontal margin slightly rimmed, weakly bilobed in dorsal view (Figs 3A View Figure 3 , 5A View Figure 5 ). Epigastric cristae low and weak, separated from postorbital cristae by narrow gap; postorbital cristae laterally expanded, not fused with epibranchial tooth. Epibranchial region gently depressed; mesogastric region gently convex. External orbital angle bluntly triangular, distinctly separated from anterolateral margin by V-shaped wide gap (Figs 3A View Figure 3 , 5A View Figure 5 ). Epibranchial tooth distinct, bluntly angular. Anterolateral margin of carapace distinctly cristate, lined with approximately 20 granules; bent inward posteriorly. Posterolateral surface smooth, with oblique striae, converging towards posterior carapace margin (Figs 3A View Figure 3 , 5A View Figure 5 ). Orbits large; supraorbital and infraorbital margins cristate. Sub-orbital, pterygostomial, subhepatic regions covered with striae. Epistome posterior margin narrow longitudinally; median lobe triangular, lateral margins sinuous (Fig. 3B View Figure 3 ).

Maxilliped 3 exopod reaching nearly 1/2 of merus length, with long flagellum, slightly longer than width of merus. Merus subrectangular, 2 times as wide as long. Ischium subtrapezoidal, about 1.4 times as long as wide, with distinct sulcus (Fig. 4B View Figure 4 ).

Chelipeds (pereiopod 1) strongly unequal in males, subequal in females. Merus trigonal in cross section. Carpus surface gently depressed, with spine at inner distal angle and spinule at base in both males and females. Palm of lager chela about 1.3-1.5 times as long as high in males, 1.3-1.6 times in females. Dactylus of larger chela 0.6-1.0 times as long as palm in males, practically same proportion in females. Inner margin of fingers lined with granular teeth; fingers of lager chela leaving small gap while smaller one without gap when closed in both males and females (Figs 3A View Figure 3 , 4A View Figure 4 , 5A View Figure 5 ).

Ambulatory legs (pereiopod 2-5) slender, with setae; pereiopod 3 longest, merus 0.5-0.6 times as long as carapace length. Pereiopod 5 propodus about 2.0 times as long as broad in both males and females, 0.8-0.9 times as long as dactylus; dactylus gently curved (Figs 3A View Figure 3 , 5A View Figure 5 ).

Male thoracic sternum generally smooth, pitted; sternite 1 triangular; sternite 2-3 fused without visible sutures. Male sternopleonal cavity relatively deep, exceeding imaginary line connecting posterior edges of cheliped coxae base. Median longitudinal suture of sternites 7, 8 deep. Tubercle of abdominal lock positioned at approaching mid-length of sternite 5. Sutures between sternites in female indistinct (Fig. 4C, D View Figure 4 ). Female vulvae ovate, medium-sized, occupying anterior 2/3 length of sternite 6 (Fig. 5B View Figure 5 ).

Male pleon and telson triangular; pleonal somites 3-6 gradually narrowed longitudinally, lateral margins forming gently concave line with thoracic sternum; pleonal somite 6 about 2.2 times as wide as long; telson about 1.3 times as wide as long (Fig. 4C View Figure 4 ). Female pleon and telson broadly ovate (Fig. 5B View Figure 5 ).

G1 slender, tip of terminal segment exceeding beyond pleonal locking tubercle and suture between thoracic sternites 4 and 5 (Fig. 4D View Figure 4 ). Subterminal segment about 1.7 times as long as terminal segment; edges of dorsal lobe curled; 2 lobes of terminal segment strongly unequal, dorsal lobe longitudinally extended, oval, ventral lobe blunt, reaching 1/2 length of terminal segment (Fig. 6A-D View Figure 6 ). G2 slender, longer than G1 (Fig. 6A, E View Figure 6 ).

Remarks.

Consistent with the diagnostic characters of Sinolapotamon , Sinolapotamon cirratum sp. nov. has a gently convex dorsal surface, long flagellum of the third maxilliped exopod and unequal lobes of the G1 terminal segment (Figs 3A View Figure 3 , 4B View Figure 4 , 7A View Figure 7 ). The dorsal lobe of the G1 terminal segment in S. cirratum sp. nov. is long and oval, which is similar to that of S. anacoluthon . The two species can nevertheless be distinguished by the ratio of the subterminal segment to the terminal segment of G1, which is 1.7 in S. cirratum sp. nov. and 1.1 in S. anacoluthon (Fig. 7A, C View Figure 7 ). When compared with S. patellifer , S. auriculatum and S. palmatum , the new species could be easily distinguished by the shape of the dorsal lobes and ventral lobes. The ventral lobe of S. cirratum sp. nov. is bluntly angular, while those of the other species in Sinolapotamon are pointed or shortly pointed (Fig. 7A, B, D, E View Figure 7 ). They also differ in comparative length of the ventral lobe relative to the terminal segment of the G1 (see Table 3 View Table 3 ). Additional differences among the known species of Sinolapotamon are provided in Table 3 View Table 3 .

Etymology.

The new species is named Sinolapotamon cirratum sp. nov. because of the curled edges of the dorsal lobe of the G1. In the Latin, ‘cirratus’ means ‘curled’.

Ecology.

The specimens were collected from puddles in the Duqiaoshan Forest Park. These crabs live in the shallow water or under the wet stones (Fig. 8A, B View Figure 8 ).

Distribution.

China: Guangxi Zhuang Autonomous Region: Rong County, Yulin City.