Trucidocynodon is an extinct, monotypic genus of cynodont from Upper Triassic of Brazil. Trucidocynodon riograndensis is the only species descript for genus. Trucidocynodon riograndensis, the sole species in Trucidocynodon, lived in what is now southern Brazil 220 million years ago. Fossils of Trucidocynodon were discovered in Santa Maria Formation outcrops in Paleorrota geopark Agudo. T. riograndensis is similar to the Ecteninion lunensis from the Upper Triassic Ischigualasto formation in Argentina.