Nouveaux Helictopleurus d'Orbigny, 1915 de Madagascar et révision du « groupe semivirens » sensu Lebis, 1960 (Insecta, Coleoptera, Scarabaeidae, Oniticellini)

Within the genus Helictopleurus d’Orbigny, 1915, a new subspecies, Helictopleurus fissicollis morettoi n. ssp., belonging to the “viridans group”, and four new species, H. cambeforti n. sp., H. dorbignyi n. sp., H. pseudoniger n. sp. and H. tamatavensis n. sp., belonging to the “semivirens group”, are described and compared with their most related species. Lectotypes are designated for Helictopleurus aeneoniger Lebis, 1960, Helictopleurus niger d’Orbigny, 1915 and Helictopleurus semivirens d’Orbigny, 1915. In addition, on the basis of external characters, H. tristis d’Orbigny, 1915 and H. gibbicollis (Fairmaire, 1895) are removed from the “semivirens group” to the “quadripunctatus group”. A new identification key is proposed for the “semivirens group”, including the newly described species. The catalogue of the Helictopleurina is given with the correct group assignation for the species belonging to “viridiflavus group” and “fungicola group”.