Three classes of metataxa are recognized—metaspecies, mixotaxa, and ambitaxa. Until such time that a metaspecies is shown to be monophyletic, paraphyletic, polyphyletic, or a mixotaxon or ambitaxon, it is considered to include organisms that are potential direct (but not necessarily the closest) ancestors to taxa subsequent to it on the cladogram. Metaspecies are recognized only at the species level, where potential ancestry must be from some group of organisms within this taxonomic level. The constituent members of a metaspecies are always organisms; if not, any larger clusters such as populations would dissolve to organisms because such clusters in a metaspecies (and a potential ancestor) do not possess autapomorphies. Mixotaxa and ambitaxa can occur at any level in the taxonomic hierarchy. At the species level, however, they are rejected as potential direct ancestors because constituent members either have autapomorphies that preclude them from potential ancestry (mixospecies) or incongruously share character states with other members (ambispecies). Because they represent incomplete or incongruous information pertaining to phylogeny, mixotaxa and ambitaxa are restricted to previously named taxa and are denoted by two (**) or three (***) asterisks, respectively. Examples of all three kinds of metataxa are given: (1) metaspecies, e.g., various member species within the extinct archaic ungulates “Anisonchus” and Oxyacodon**, and (sub)species within the extant long-nosed snake Rhinocheilus; (2) mixotaxon, e.g., the extinct archaic ungulate Oxyacodon**; and (3) ambitaxon, e.g., the extant Iguanidae*** as formerly recognized. Because at least some metaspecies (recognized by a single asterisk) do have historical reality as ancestors, they can be named. Metaspecies should be recognized because they include historically real taxa (some metaspecies that are ancestors) and because they provide clarity of taxonomic usage that is not available with present conventions.