Sinolapotamon anacoluthon (Kemp, 1918)

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/67C45D86-5B9A-5924-A67F-0302904ED4F6
treatment provided by	ZooKeys by Pensoft
scientific name	Sinolapotamon anacoluthon (Kemp, 1918)
status

Treatment

Figs 2 View Figure 2 , 7C View Figure 7

Potamon (Potamon) anacoluthon Kemp, 1918: 243, fig. 5.

Cryptopotamon anacoluthon Ng & Dudgeon, 1992: 741, figs 3B, 4, 5. - Ng et al. 2008: 161 (list).

Sinolapotamon anacoluthon Dai, 1999: 150, fig. 79.

Material examined.

China • 4 ♂♂ (18.40 × 16.34 mm, 20.26 × 18.40 mm, 21.64 × 18.60 mm, 19.26 × 17.04 mm); Yangtaishan Forest Park, Shenzhen , Guangdong Province; 22.6587°N, 113.9837°E; July 2022; Sheng Yu leg.; NCU MCP 434001-434004 GoogleMaps • 1 ♂ (25.84 × 22.76 mm); same collection data as above; NCU MCP 434101 GoogleMaps • 3 ♀♀ (26.34 × 23.58 mm, 28.84 × 24.38 mm, 24.31 × 20.95 mm); same collection data as above; NCU MCP 434102-434104 GoogleMaps .

Diagnosis.

Carapace gently convex, regions indistinct. Cervical groove shallow, indistinct; H-shaped groove depressed and distinct (Fig. 2A View Figure 2 ). Epigastric cristae weak, postorbital cristae flat, indistinct. External orbital angle triangular, with about 5 small granules. Epibranchial tooth sharp, distinctly separated with external orbital angle by V-shaped gap. Anterolateral margin of carapace cristate, with about 12 granules (Fig. 2A View Figure 2 ). Maxilliped 3 exopod reaching nearly 1/3 of merus length, with long flagellum (Fig. 2C View Figure 2 ). Chelipeds (pereiopod 1) strongly unequal (Fig. 2A, B, D View Figure 2 ). G1 slender, subterminal segment about 1.1 times as long as terminal segment; 2 lobes of terminal segment strongly unequal, dorsal lobe longitudinally extended, oval shaped, ventral lobe sharp and short, reaching 3/7 of terminal segment (Figs 2E View Figure 2 , 7C View Figure 7 ).

Ecology.

The species is usually inhabiting the clear hill streams at an altitude below 50 m. Stones could serve as shelter and leaf mould could serve as food (Dai, 1999).

Distribution.

China: Shenzhen of Guangdong Province (present record) and Hong Kong.

Remarks.

The specimens from Shenzhen, with gently convex dorsal surface of carapace, indistinct postorbital cristae, sharp epibranchial tooth, unequal lobes of the terminal segment of the G1 (Fig. 2 View Figure 2 ), and other characteristics, agree well with the descriptions and illustrations in Ng and Dudgeon (1992) and Dai (1999). The ratio of the subterminal segment to the terminal segment of G1 calculated in this study is 1.1 (Fig. 7C View Figure 7 ), which is equal to that in Dai (1999) and slightly smaller than that in Ng and Dudgeon (1992) (1.17). Although the specimens are not from Hong Kong, they could still be determined as S. anacoluthon based on morphological examination and the proximity of their collection site to Hong Kong (Fig. 1 View Figure 1 ).

Ng and Dudgeon (1992) listed the differences between Cryptopotamon and Sinolapotamon , including carapace, epigastric cristae, postorbital cristae, epibranchial tooth, and the ratio of the subterminal segment to the terminal segment of the G1. We, however, noticed that those differences are interspecific, while two or more species sharing the same character state with the remaining species is not. For instance, S. anacoluthon has a gently convex carapace similar to that of S. cirratum sp. nov. but different from the remaining congeners (Figs 2A View Figure 2 , 3A View Figure 3 ). The weak epigastric cristae of S. anacoluthon are consistent with those of S. auriculatum and S. cirratum sp. nov. (Fig. 2A View Figure 2 ; see Zhu et al. 2010: figs 1a, 6a). The indistinct postorbital cristae of S. anacoluthon are comparable with those of S. auriculatum and S. palmatum (Fig. 2A View Figure 2 ; see Zhu et al. 2010: figs 1a, 6a). The sharp epibranchial tooth is consistent with that of S. auriculatum (Fig. 2A View Figure 2 ; see Zhu et al. 2010: fig. 1a). The different ratios of the subterminal segment to the terminal segment of the G1 could only be regarded as interspecific differences. Most importantly, all five species have accordant fundamental types of G1 (Fig. 7 View Figure 7 ).