Article 42. The genus group
The genus group, which is next below the family group and next above the species group in the hierarchy of classification, encompasses all nominal taxa at the ranks of genus and subgenus (see also Articles 10.3 and 10.4).
Genus-group nominal taxa and their names are subject to the same provisions whatever their rank, except when these apply explicitly at one rank alone.
42.2.1. The names established expressly for certain assemblages of taxonomic convenience known as "collective groups" and names for trace fossils (ichnotaxa) established at the genus-group level are to be treated as genus-group names in the meaning of the Code [Art. 10.3], unless there is a statement to the contrary in a particular Article (as in Articles 13.3.2, 13.3.3, 23.7, 42.3.1, 66, 67.14); each takes its original author and date.
Examples. (a) Of a collective group name: Agamofilaria Stiles, 1907 (Nematoda). (b) Of names proposed for trace fossils: Helicolithus Azpeitia Moros, 1933 and Stelloglyphus Vyalov, 1964.