Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea) Author Ng, Peter K. L. Author Castro, Peter text Zootaxa 2016 4209 1 1 182 journal article 37321 10.11646/zootaxa.4209.1.1 2de5b7bf-3975-458a-b200-07ec69f4e013 1175-5326 272646 849BAB5C-464A-4B4A-A586-5742411EDC01 Key to species of Megaesthesius 1. Outer margins of ischium and merus of third maxilliped unarmed ( Fig. 34 B). Ventral margin of chela unarmed, pollex rela- tively slender; cutting margins of fingers of major male chela unarmed ( Fig. 48 E) [ Japan ; East China Sea ]...... M. yokoyai - Outer margins of ischium and merus of third maxilliped lined with small teeth or spines (e.g., Fig. 34 A). Ventral margin of chela dentiform, pollex relatively stout; cutting margins of fingers of major male chela with small teeth (e.g., Fig. 48 C)....2 2. Lateral margins of carapace with numerous prominent sharp teeth and spines ( Fig. 19 A, B) [ Singapore ; Vietnam ; South China Sea ; questionably from Andaman Sea]............................................................ M. sagedae - Lateral margins of carapace with lobiform teeth, the margins can be armed with spinules (e.g., Figs. 19 M, 20A, B)........3 3. Fingers of chela prominently longer than palm ( Fig. 48 D). Ambulatory legs, especially meri, conspicuously long, relatively slender ( Fig. 20 A, B) [ Philippines ].......................................................... M. migmus n. sp. - Chela unknown. Ambulatory legs, especially meri, relatively shorter ( Fig. 19 Q, R) [ Western Australia ]....... M. westralia