The purpose of this application, under Articles 23.9.3, 81.1 and 81.2.3 of the Code, is to conserve the name Pachylemur Lamberton, 1948 (Primates, lemuridae), a genus of subfossil Malagasy lemurs, by suppressing the senior subjective synonym Palaeochirogalus Grandidier, 1899 and by designating a type species for the genus Pachylemur Lamberton. Palaeochirogalus Grandidier has never seen any substantial usage whereas Pachylemur Lamberton, 1948 is in universal use; however, Pachylemur Lamberton, 1948 is unavailable because no type species was designated in the original publication. Filhol (1874) previously used the name Pachylemur for a ‘groupe’ of Paleogene primates; we conclude that this name, under either Filhol's or Palmer's (1904) authorship and, in either case, ambiguous as regards availability should be formally suppressed at the genus-group level to prevent confusion.