Specimens of theAcartiasubgenusAcartiurawhich are closely related toA. clausiiGiesbrecht, 1889 were examined from European waters, the east and west coasts of the United States, Japan, Australia, and New Zealand. The speciesA. ensiferaBrady, 1899 andA. simplexSars, 1905 are redescribed,A, hudsonicaPinhey, 1926 is elevated from subspecific to specific status, and five new species (A. jilletti, A. lefevreae, A. omorii, A. teclae,andA. tranteri) are described. A key is given to all known species ofAcartiura.