Type specimens and names assigned to Coprophanaeus (Megaphanaeus) d'Olsoufieff, 1924, the largest New World dung beetles (Coleoptera: Scarabaeidae: Phanaeini).

Currently 13 species-group names assigned to the subgenus Megaphanaeus of Coprophanaeus are deemed available (or 'potentially available'), four of which denote valid species. In the present work we review the nomenclatural history of those names and conclude that two of them, Scarabaeus satelles Lichtenstein, 1796 and Copris ajax Sturm, 1826, are unavailable. For the other 11 names, we found type specimens of five, Scarabaeus bellicosus Olivier, 1789, Copris ensifer Germar, 1821, Phanaeus septentrionalis Pêssoa, 1934, P. vicinus Martínez, 1944, and P. vicinus var. argentinus Martínez, 1944. Two lectotypes are designated, one for Copris ensifer and other for Phanaeus septentrionalis. We were unable to locate the type series of the four names described by Castelnau (1840), i.e. Phanaeus ducalis, P. sylvanus, P. heros and P. miles, and of P. bonariensis Gory, 1844 and Scarabaeus lancifer Linné, 1767. For the latter, based on some iconotypes, we found that its type series was composite, including specimens of two different Megaphanaeus species, and, in addition, it was mixed with Copris ensifer type series. In order to fix the name to a sole species, a neotype is designated for Scarabaeus lancifer. The history of the names are presented in detail, and the application of these names to species is briefly re-discussed.