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| Sinolapotamon cirratum Lu, Zhang & Zou, 2023 |
Abstract
The systematics of the potamid freshwater crab Cryptopotamon anacoluthon (Kemp, 1918) is clarified, and its generic position in Sinolapotamon Tai & Sung, 1975, is confirmed based on morphological comparisons, geographical information and phylogenetic analyses. A new species of Sinolapotamon, Sinolapotamon cirratum sp. nov. is described from the Guangxi Zhuang Autonomous Region of China. Sinolapotamon cirratum sp. nov. is distinguished from its congeners by the combination of characters of its carapace, third maxilliped, anterolateral margin, and unique male first gonopod. Phylogenetic analyses based on partial COX1, 16S rRNA and 28S rRNA genes also support the species as new.
Key words: Freshwater crabs, molecular phylogeny, systematics, taxonomy
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| Sinolapotamon cirratum sp. nov., holotype male (17.90 × 15.50 mm) (NCU MCP 434201) A overall dorsal habitus B frontal view of cephalothorax. Scale bars: 1 cm. |
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| Sinolapotamon cirratum sp. nov., holotype male (17.90 × 15.50 mm) (NCU MCP 434201) A outer view of chelipeds B left third maxilliped C anterior thoracic sternum, pleonal somites 4–6 and telson D sternopleonal cavity with G1. Scale bars: 5 mm. |
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| Sinolapotamon cirratum sp. nov., paratype female (17.42 × 15.45 mm) (NCU MCP 433901) A overall dorsal habitus B sternopleonal cavity with vulvae. Scale bars: 1 cm. |
Sinolapotamon cirratum sp. nov.
Diagnosis: Carapace subquadrate, regions indistinct; dorsal surface gently convex, anterolateral region weakly rugose. Cervical groove shallow and wide; H-shaped groove shallow (Figs 3A, 5A). 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, 5A). Maxilliped 3 exopod reaching nearly 1/2 of merus length, with long flagellum, slightly longer than width of merus (Fig. 4B). Chelipeds (pereiopod 1) strongly unequal in males, subequal in females (Figs 3A, 4A, 5A). 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, 7A). Female vulvae ovate, medium-sized, occupying anterior 2/3 length of sternite 6 (Fig. 5B).
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’.
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| A Sinolapotamon cirratum sp. nov. in the wild B general habitat. |
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).
Distribution: China: Guangxi Zhuang Autonomous Region: Rong County, Yulin City.
Yuan-Biao Lu, Yi-Xuan Zhang and Jie-Xin Zou. 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: 155-173. DOI: 10.3897/zookeys.1166.101737