Villalobosius is a genus of crabs in the family Pseudothelphusidae, containing a single species, Villalobosius lopezformenti.^[1] It lives in the northern part of the state of Oaxaca, Mexico, on the Isthmus of Tehuantepec, and is adapted to a troglobitic lifestyle.^[2]

The species was originally described as Stygothelphusa lopezformenti in 1991, but the genus name Stygothelphusa was discovered to be a junior homonym of Stygothelphusa Ng, 1989, and a replacement name, Villalobosus, was created in 2000.^[1][3] This was also found to be a junior homonym, of the subgenus Villalobosus Holthuis, 1972 in the crayfish genus Procambarus, and so it, too, was replaced.^[4] The genus is therefore currently known as Villalobosius.^[4]