New data on the systematics and biogeography of the Neotropical ant genus Thaumatomyrmex Mayr, 1887 (Insecta, Hymenoptera, Formicidae) with description of a new species from the inland paleo-dunes of the middle São Francisco River, northeastern Brazil

The Neotropical ant genus Thaumatomyrmex Mayr, 1887 (Ponerinae, Ponerini) is currently represented by 13 valid species divided into three taxonomic groups, distributed between southern Mexico and northern Argentina, with a presence in the Caribbean islands. We propose the first morphological phylogeny and biogeographical hypotheses for the genus. Based on this morphological phylogeny, we redescribe the genus. The phylogeny revealed the “ferox species group” to be paraphyletic, while the mutilatus species-group forms a clade defined by 12 synapomorphies, which we used to give a new diagnosis. We give the definition of the two species already described of this mutilatus-group and compare them with the description of a new species, Thaumatomyrmex carranca Celante & Jahyny sp. nov. from the São Francisco Dunes district in the Caatinga Dominion, in northeastern Brazil. We present data on the natural history and conservation status of the new species. We provide an identification key for the three taxonomic groups and for the worker morphotype of all described Thaumatomyrmex species of the “ferox” and mutilatus species groups.