Iridomyrmex, or the rainbow ant (referring to its blue-green iridescent sheen) is a genus of ant first described by Austrian entomologist Gustav Mayr in 1862. He placed it in the subfamily Dolichoderinae of the family Formicidae. There are 79 described species and five fossil species. Most of these ants are native to Australia; others are found in several countries and islands in Asia and other areas in Oceania, and they have been introduced to Brazil, New Zealand and the United Arab Emirates. Fossil species are known from China, France and the United States.