Species of the genusSadocusSørensen, 1886 are conspicuous gonyleptids that occur in Chile and Argentina. Here, the genus is revised for the first time and the cladistic analysis based on morphological characters does not corroborate its monophyly unless a phylogenetically unrelated species is excluded (explained further on). A new classification is proposed for the seven species left in the genus and considered valid, of the 13 nominal species previously recognized. Two out of the seven valid species are considered as species inquirendae:Sadocus allermayeri(Mello-Leitão, 1945) [=Carampangue allermayeriMello-Leitão, 1945] andSadocus nigronotatus(Mello-Leitão, 1943) [=Carampangue nigronotatumMello-Leitão, 1943]. The following synonymies are proposed:Sadocus bicornis(Gervais, 1849) [original combination =Gonyleptes bicornisGervais, 1849] is a junior synonym ofSadocus asperatus(Gervais, 1847) [=Gonyleptes asperatusGervais, 1847];Sadocus conspicillatusRoewer, 1913,Sadocus exceptionalis(Mello-Leitão, 1946) [=Araucanoleptes exceptionalisMello-Leitão, 1946] andSadocus guttatusSørensen, 1902 are junior synonyms of the valid nameSadocus polyacanthus(Gervais, 1847) [=Gonyleptes polyacanthusGervais, 1847]; andSadocus calcar(Roewer, 1913) [=Lycomedes calcarRoewer, 1913] is a junior synonym of the valid nameGonyleptes horridusKirby, 1819.Sadocus brasiliensisSoares & Soares, 1949 is not congeneric with Argentinean/Chilean species of the genus according to the cladistic analysis and is here synonymized withDiscocyrtus catharinensis(Mello-Leitão, 1923 [=Sadocus catharinensisMello-Leitão, 1923]).
