Brachymyrmex patagonicus is the type species of the genus, and is a small, shiny, light brown to dark brown species with reduced pilosity. The original type material used by Mayr (1868)to describe the B. patagonicus cannot be located, prompting the species to be redescribed based on Chilean material also examined and determined by Mayr (Quirán et al., 2004). The redescription was part of a larger effort to clear up the confusion surrounding Brachymyrmex taxonomy (Quirán, 2005;2007), but several errors concerning the erroneously small size of the workers and queens of B. patagonicus were also published (MacGown et al., 2007). Brachymyrmex patagonicus is native to at least the South America region of the Neotropics (Quirán et al., 2004), and is introduced to the Southeastern United States (MacGown et al., 2007), and at least the Netherlands in Europe (Boer & Vierbergen, 2008). A review of B. patagonicus as an emerging pest species in the Gulf Coast region of the United States provides a thorough account of the taxonomy, invasion history and biology (MacGown et al., 2007). The authors suggest that B. patagonicus shows considerable potential as a nuisance species; perhaps comparable to the effects Tapinoma melanocephalum has in tropical and subtropical regions.