Article 20. Genus-group names ending in -ites, -ytes or -ithes given to fossils. A name formed by adding the suffix -ites, -ytes or -ithes to the whole or the stem of an available name of a genus-group taxon, and applied to fossils to distinguish them from extant members of that taxon, without clear evidence of intent to establish a new genus-group taxon, is available only for the purposes of the Principle of Homonymy. Such a name cannot be used as the valid name of a taxon [Art. 23.1] or as the basis of a family-group name [Art. 11.7.1.4].