The Six Principles of the ICZN: Coordination.

Now that we've established Binomial Nomenclature and Priority as founding principles of zoological nomenclature, we at least have a stable system of classification. However, there are still some loose ends to tie up.

Article 36. Principle of Coordination.

36.1. Statement of the Principle of Coordination applied to family-group names. A name established for a taxon at any rank in the family group is deemed to have been simultaneously established for nominal taxa at all other ranks in the family group; all these taxa have the same type genus, and their names are formed from the stem of the name of the type genus [Art. 29.3] with appropriate change of suffix [Art. 34.1]. The name has the same authorship and date at every rank.

Articles 43 and 46 provide the same statements in relation to genus-group and species group names.

Essentially, when a new name is created in the family group (superfamily, family, subfamily, tribe, subtribe), genus group (genus and subgenus) or species group (species and subspecies), by this principle all other names are "created" on the same date, even if they are not discussed at that time. They exist in a sort of potential state until they are first talked about, at which point the author and date associated with the "new" taxon is referred to publication by which it was created coordinately.

For example, if I published a new family, Ecksidae Burington 2011, by Principle of Coordination Superfamily Ecksoidea, Subfamily Ecksinae, Tribe Ecksini, and Subtribe Ecksina would all be considered considered created at that point, even though I don't talk about them. If another author comes along later and decides to discuss the subfamily Ecksinae, even though it had never been formally discussed before that point, it would still be considered to be Ecksinae Burington 2011 by this principle.

This seems to be a completely unnecessary Principle until you consider the habits of taxonomists. We often enjoy raising or lowering the ranks of various groups to suit ease of classification and/or personal taste. If these groupings weren't already created in potential, you can imagine the cacophony of names and dates that could arise from this process. Again, like all other aspects of The Code, the Principle of Coordination is meant to preserve the stability of zoological nomenclature, in this case by stopping problems before they even arise. This principle also prevents the orphaning of taxa by the "type" clause; I'll be discussing typification more later.