Taxonomy and phylogenetics of <i>Tmesiphantes</i> Simon, 1892 (Araneae, Theraphosidae)

The tarantula genus <i>Tmesiphantes</i> Simon, 1892 (Theraphosinae) includes nine valid species, with records for the states of Bahia (<i>T. nubilus</i>, <i>T. caymmii</i>, <i>T. amadoi</i>, <i>T. bethaniae</i>, <i>T. hypogeus</i>, and <i>T. mirim</i>), Minas Gerais (<i>T. perp</i> and <i>T. riopretano</i>), and Pará (<i>T. aridai</i>), all in Brazil. In the present study, we reviewed the taxonomy of the <i>Tmesiphantes</i> species and performed a phylogenetic analysis using morphological characters. Four new species are described: <i>T. amazonicus</i> sp. nov., <i>T. guayarus</i> sp. nov., <i>T. nordestinus</i> sp. nov., and <i>T. raulseixasi</i> sp. nov., which expand the geographic distribution for the following states in Brazil: Goiás, Mato Grosso, Piauí, Paraíba, and Pernambuco, occurring in the Caatinga shrublands Cerrado savannas, Atlantic rain forest, and Brazilian Amazon. Phylogenetic analysis included 30 terminal taxa and 37 characters, including representatives of nine genera of Theraphosinae. The <i>Tmesiphantes</i> species formed a monophyletic group with the species hitherto included in <i>Melloleitaoina</i> and <i>Magulla</i>, with the latter being paraphyletic, which led us to propose the synonymy of these three genera. An updated diagnosis is proposed for the genus <i>Tmesiphantes</i>, which now comprises 19 species, occurring in major Brazilian biomes and in Argentina. A distribution map that includes all <i>Tmesiphantes</i> species and notes on their distributions are provided.