Armadillos are New World placental mammals with a leathery armour shell. The Chlamyphoridae and Dasypodidae are the only surviving families in the order Cingulata, part of the superorder Xenarthra, along with the anteaters and sloths. The word armadillo means "little armoured one" in Spanish. The Aztecs called them āyōtōchtli [aːjoːˈtoːt͡ʃt͡ɬi], Nahuatl for "turtle-rabbit": āyōtl [ˈaːjoːt͡ɬ] (turtle) and tōchtli [ˈtoːt͡ʃt͡ɬi] (rabbit). The European Portuguese word for armadillo is armadilho Portuguese pronunciation: [aɹmaˈdʒiʎu] and in South America the most common denomination is tatu Portuguese pronunciation: [taˈtu] which derives from the Tupi language.