A new species of Ptychognathus Stimpson, 1858, from East and Southeast Asia, previously identified as Ptychognathus barbatus (A. Milne-Edwards, 1873) (Crustacea, Decapoda, Brachyura, Varunidae)

The right P4 and P5 of four species of Ptychognathus (dorsal view). A. P. dajie sp. nov. (holotype male, CW 13.2 mm, ZRC 2024.0072); B. Ptychognathus barbatus (male, CW 10.2 mm, ZRC 2019.1806); C. Ptychognathus guijulugani (male, CW 8.8 mm, NCHUZOOL 17334); D. Ptychognathus pusillus (male, CW 13.2 mm, ZRC 2013.1844). Scale bars: 3 mm.