"Phaeacius" is in the subfamily Spartaeinae, which is thought to be primitive.Molecular phylogeny, a technique that compares the DNA of organisms to reconstruct the tree of life, indicates that "Phaeacius" is a member of the tribe Spartaeini, that Spartaeinae is basal (quite similar to the ancestors of all jumping spiders), and that "Phaeacius" is closely related to "Portia" and "Spartaeus".