M. americanus

M. americanus may refer to:
 * Menticirrhus americanus, a kingcroaker species in the genus Menticirrhus
 * Merganser americanus, a duck species
 * Metasiro americanus, a harvestman species in the genus Metasiro
 * Monomitopus americanus, an eel species in the genus Monomitopus
 * Morone americanus, a bass species