Article 37. Nominotypical taxa
When a family-group taxon is subdivided, the subordinate taxon that contains the type genus of the superior taxon is denoted by the same name (except for suffix) with the same author and date [Art. 36.1]; this subordinate taxon is termed the "nominotypical taxon".
Example. The family TIPULIDAE Latreille,  (type genus Tipula Linnaeus, 1758) is divided into a number of subfamilies, each named after its own type genus. The subfamily containing Tipula is called TIPULINAE Latreille,  and is the nominotypical subfamily.
If the name in use for a family-group taxon is unavailable or invalid it must be replaced by the name valid under Article 23.3.5; any subordinate taxa containing the type genus of the substitute nominal taxon (and therefore denoted by the valid family-group name, with appropriate suffixes) become nominotypical taxa.