Abstract
Tetraodon palustris, new species, is described from the Mekong basin of Thailand. Tetraodon palustris differs from T. cochinchinensis and T. fangi in having no ocellus on the flank and spinules dorsally from the interorbital region to the end of the dorsal-fin base. Tetraodon cochinchinensis is distinguished from T. fangi by having a longer snout (43.5–49.2% HL in T. cochinchinensis vs. 37.9–41.1% HL in T. fangi) and is covered with spinules dorsally from the front of the nasal organs to the end of the dorsal-fin base (vs. from the front of the eyes to the end of the dorsal-fin base in T. fangi).