Leptodactylus knudseni is widely distributed in the greater Amazon basin from Bolivia and Brazil north to Colombia, Venezuela, and the Guianas. Its presence on Trinidad is based upon a single specimenMCZ 8663. R. R. Mole collected or presented, the specimen to the MCZ, in May 1915. This species is in the pentadactylus Group and early references to Leptodactylus pentadactylus on Trinidad probably refer to this species. Barbour (1914) suggested that L. pentadactylus may have been exterminated on Trinidad because of its culinary value. The species presence on Trinidad has been reported only once in the early literature from the Island (Mole and Urich, 1894a) and they suggested it may have been exterminated by the introduction of the mongoose. Hardy (1982) suggested a member of the pentadactylus Group may also occur on Tobago, recounting Ober’s (1898) description of a gourmet frog dinner on Tobago and a subfossil frog femur from a cave. The presence of an extant population of this frog on either island is not substantiated in this work.