Description of a new species of Setosamon Yeo & Ng, 2007 (Decapoda: Brachyura: Potamidae) from Sakon Nakhon Province, northeastern Thailand Author Tan, Zhi Wan Author , Jose Christopher E. Mendoza Author Yeo, Author Darren C. J. text Raffles Bulletin of Zoology 2022 2022-12-19 70 572 579 journal article 10.26107/RBZ-2022-0032 2345-7600 13256881 EEB11131-3D0E-49BB-B630-44DF04B9A23E Genus Setosamon Yeo & Ng, 2007 Setosamon Yeo & Ng, 2007: 293 . Type species. Potamon ubon Ng & Naiyanetr, 1993 , by original designation. Remarks. Setosamon Yeo & Ng, 2007 , now includes three species, namely S. somchaii ( Ng & Naiyanetr, 1993 ) , S. ubon ( Ng & Naiyanetr, 1993 ) , and S. sakon , new species (see below). Setosamon species are characterised by the nearly confluent epigastric and postorbital cristae, shallow sternopleonal cavity, broadly triangular male pleon, coarse setae on the third maxillipeds and ambulatory legs, and broad, well developed dorsal flap on the G1 terminal segment. In this respect, Setosamon shares many similarities in carapace morphology with Pilosamon Ng, 1996 . However, Setosamon can be easily differentiated from Pilosamon in the G1 terminal segment being subcylindrical with its distal tip bluntly rounded and with a relatively low and swollen dorsal flap (versus G1 terminal segment subconical, tip pointed with relatively high, flat dorsal flap in Pilosamon ); and the groove for the G2 being dorsal (sternal) in position (versus groove for G2 marginal, mesial in position in Pilosamon ) ( Fig. 1A–D ; Ng & Naiyanetr, 1993 : figs. 40B–E, 41B–E; Ng, 1996 : fig. 2; Yeo & Naiyanetr, 2010 : fig. 2). Distribution. Nakhon Phanom , Ubon Ratchathani and Sakon Nakhon Provinces, all in northeastern Thailand .