The superfamily Bogidielloidea is one of the most wide-ranging hypogean amphipod taxa currently known, comprising over 130 species in 43 genera occurring on every continent except Antarctica. This large distribution among such cryptic organisms is curious, especially when combined with weak morphological characters uniting the superfamily. A unique new genus and species of bogidielloid amphipod, Simplexia longicrus, gen. et sp. nov., described from Terrell County, Texas, sheds light on the evolutionary relationships within this grouping. Molecular phylogenetic analyses of the order Amphipoda using two nuclear genes and one mitochondrial gene reveal that this species and the sympatric Parabogidiella americana form a clade removed from other sequenced members of Bogidiellidae sensu stricto, and, as such, the two species are placed in the newly erected Parabogidiellidae, fam. nov. Additional phylogenetic analyses of the cosmopolitan Bogidiellidae are recommended to further resolve its systematics.