The taxonomy of the genus Microbuthus is reviewed, and a new species from Oman and Yemen, M. satyrus sp. n., is described and fully illustrated with color photographs of live and preserved specimens, as well as of its habitat. It is compared to the closely similar species M. litoralis, which we also illustrate. Synonymy of the type species M. pusillus Kraepelin, 1898 with M. litoralis (Pavesi, 1885) is confirmed, and the species is recorded for the first time from Yemen. Hemispermatophores of M. satyrus sp. n., M. gardneri Lowe, 2010, and M. kristensenorum Lowe, 2010 are illustrated and compared, and we also describe the karyotypes of these three Microbuthus species. The number of chromosomes is the same in all analyzed species (2n=26).