Paxillus is a neotropical genus belonging to the subfamily Passalinae widespread from Mexico to Argentina. Brazil is known to harbor five species belonging to this genus with most of them presenting at head a flattened central tubercle lacking a free apex. However, one of these species, Paxillus macrocerus Reyes-Castillo & Fonseca, differs from that pattern by having a long central tubercle with a completely free apex. The present study describes and illustrates another new species, which has been found in the Brazilian Amazon, showing this same characteristic.