International Commission on Zoological Nomenclature

Article 66. Application. The provisions and recommendations of this Chapter apply equally to nominal genera and subgenera (including genus-group divisions deemed to be subgenera; see Article 10.4), but not to collective groups at the genus-group level, which have no type species [Arts. 13.3.2, 42.3.1, 67.14].

66.1. An ichnotaxon at the genus-group level proposed after 1999 must have a type species fixed for its name to be available. If established before 2000 it does not require a type species; however, one may have been, or may be, fixed in accordance with Article 69 (see also Article 13.3.3).