The Dorylinae subfamily are dominant invertebrate predators in tropical and subtropical terrestrial ecosystems. The most cryptic army ant genus of the New World is Cheliomyrmex. The only specie recognized until now to the Amazon Brazilian Basin is C. andicola , with record in the state of Acre. We provided the first record of Cheliomyrmex megalonyx to Brazil in the Amazon Basin. This record strongly reinforces the idea that more efforts are needed to reveal the diversity, distribution and biology of such hypogaeic ants.