ZooKeys 994: 1–34 (2020) A peer-reviewed open-access journal doi: 10.3897/zookeys.994.56810 RESEarcH arTicLE https://zookeys.pensoft.net Launched to accelerate biodiversity research Revision of the freshwater crabs of the Johora tahanensis (Bott, 1966) species group (Crustacea, Brachyura, Potamidae), with a key to the genus Peter K. L. Ng1 1 Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singa- pore 117377, Singapore Corresponding author: Peter K. L. Ng (
[email protected]) Academic editor: C. Magalhães | Received 22 July 2020 | Accepted 26 October 2020 | Published 17 November 2020 http://zoobank.org/DB1879C9-1904-4320-BE67-4D9F863F6775 Citation: Ng PKL (2020) Revision of the freshwater crabs of the Johora tahanensis (Bott, 1966) species group (Crustacea, Brachyura, Potamidae), with a key to the genus. ZooKeys 994: 1–34. https://doi.org/10.3897/zookeys.994.56810 Abstract The taxonomy of the potamid freshwater crabs of the Johora tahanensis (Bott, 1966) species group (Pota- moidea) is revised. Seven species are recognised, all from Peninsular Malaysia and southern Thailand, three of which are described as new. The three new species were previously identified as J. tahanensis but can be distinguished by characters of the carapace, male first gonopod, and vulva. A revised key to the 18 recognised species of Johora Bott, 1966, is provided. Keywords Freshwater crab, new species, Peninsular Malaysia, Potamoidea, taxonomy, Thailand Introduction Six genera of potamid freshwater crabs are known from the Malay Peninsula (Penin- sular Malaysia, Thailand south of the Isthmus of Kra, and Singapore):Baccazia Ng, 2018a, Demanietta Bott, 1966, Gempala Ng & Ahmad, 2016, Johora Bott, 1966, Stoliczia Bott, 1966, and Terrapotamon Ng, 1986a (see Ng 1988, 2018a, b; Yeo et al.