In this natural history note we describe and illustrate the specialized predatory behavior of the ponerine ant Thaumatomyrmex paludis from the Brazilian Amazon. This study of T. paludis implies that specialized predation on polyxenid millipedes is widespread in the genus Thaumatomyrmex. The observation that one T. paludis forager only partly depilated its prey before it started feeding suggests that complete depilation of polyxenids, as reported from T. contumax, could be most important when prey items are fed to the larvae, presumably to protect the brood from irritating bristles. Our observations provide an additional example of the sympatric distribution of two Thaumatomyrmex species, further supporting the hypothesis that the genus consists of multiple, morphologically similar species.