The Asian family Diatomyidae is known from the Early Oligocene to the present. Among living rodents, this group comprises only the recently discovered Laonastes aenigmamus from Laos. Fossil diatomyids are known from only a few sites, in which they are often rare. The discovery of Pierremus explorator gen. nov. sp. nov. in the Lower Miocene of As-Sarrar (Saudi Arabia) raises to ten the number of extinct diatomyid species recognized. Pierremus explorator is the first record of a diatomyid from the Afro-Arabian plate. This discovery provides evidence that, together with other rodents (ctenodactylids, zapodids…), the diatomyids took advantage of the corridor that was established between Afro-Arabia and Eurasia in Early Miocene times.