The goal of this paper is to provide, for the first time, a synchronic description and diachronic reconstruction of negation in Tacana, a critically endangered language of the small Takanan family in the Amazonian lowlands of Bolivia and Peru. One significant contribution of the paper is the reconstruction, for a standard negation marker, of an etymology (stand-alone negation word 'no') and type of Jespersen Cycle (from the right of the verb to the left of the verb) that are not commonly reported in general studies on negation. The proposed reconstruction also contributes to current studies on the interactions between standard negation and the Negative Existential Cycle (the general theme of the volume) in arguing that the Tacana stand-alone negation word 'no' originated in a negative existential predicate. In so doing, the paper adds to the diachronic literature on languages where a negative existential breaks into the verbal domain through a stand-alone negation stage.