Article 53. Definitions of homonymy in the family group, genus group and species group.
53.1. Homonyms in the family group. In the family group, two or more available names having the same spelling or differing only in suffix [Art. 29.2] and denoting different nominal taxa are homonyms.
Examples. The family-group names METOPIINAE Foerster,  (Hymenoptera; type genus Metopius Panzer, 1806), METOPIINI Raffray, 1904 (Coleoptera; type genus Metopias Gory, 1832) and METOPIINI Townsend, 1908 (Diptera; type genus Metopia Meigen, 1803) are homonyms. (Their homonymy was removed by the Commission emending the spellings of the latter two family-group names to METOPIASINI and METOPIAINI [Opinion 1772, 1994]).
53.2. Homonyms in the genus group. In the genus group, two or more available names established with the same spelling are homonyms.
Example. The generic names Noctua Linnaeus, 1758 (Lepidoptera) and Noctua Gmelin, 1771 (Aves) are homonyms.
53.3. Homonyms in the species group. Two or more available species-group names having the same spelling are homonyms if they were originally established in combination with the same generic name (primary homonymy), or when they are subsequently published in combination with the same generic name (secondary homonymy) (for species-group names combined with homonymous generic names see Article 57.8.1).
Example. Cancer strigosus Linnaeus, 1761 and Cancer strigosus Herbst, 1799 were established for different nominal species in the nominal genus Cancer Linnaeus, 1758, and the specific names are therefore primary homonyms. For an example of secondary homonymy see Article 57.3.1.
53.3.1. The variant spellings of species-group names listed in Article 58 are deemed to be identical spellings for the purposes of the Principle of Homonymy.
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|FranciscoWelterSchultes||Art. 53.2: see also Art. 54, with more examples.
It seems increasingly necessary to give a clear statement to reject the concept of a name classified as a "homonym and junior objective synonym" in favour to a subsequent use. This is because recently an increasing trend can be observed to regard subsequent uses of previously established names as new names. This has not been done in this extent before, and if the practice continues, a crucial portion of zoological nomenclature gets a very different direction (because Art. 49 would sooner or later be chased out of force, if one simply defines a sensu name or misidentification as a new name).
Such a rule should include two provisions, and also incorporate the delimitation between new name and "homonym and junior subjective synonym".
1 - For a subsequent use it is not necessarily demanded that the second author knew the first source, or attributed to name to the same manuscript author, or referred to the same published pre-Linnean source.
2 - Decisive are only the spelling and the taxonomic concept in the judgement (or presumed judgement) of the second source. The second author must have used the name in subjectively the same taxonomic sense. This means that there must be no evidence in the second source that if the second author had known that the first author had established the name, the second author would not have used it and instead would have selected a different name for his or her concept. Taxonomic concepts used at later dates must not be taken into consideration.
Such a rule would be in line with usual practice and with the Glossary's definition ("homonym", sentence 2).
In vertebrate nomenclature Latin vernacular names were often independently used by various subsequent authors for genera, Linnean authors who did not know each other but who used the names in subjectively the same senses. Usual practice is to take the name from the oldest source.
The same applies to situations at which specific names were borrowed for the generic level, by various subsequent authors who did not know each other. This procedure usually produced what has recently been called a "homonym and junior objective synonym". An example is the gastropod genus Mitra, established subsequently by Lamarck 1798, a few weeks later independently by [Röding] 1798, used in both source principally for a group of species that contained Voluta mitra Linnaeus, 1758.
The present-day problem becomes increasingly evident in genus-group names when a first author classified a few species in a genus without fixing a type, and a second author classified a few other very similar species in a genus for which the same name was selected. The decision (new name or not) in such a case can only be taken under the taxonomic concepts applied in what I call here "the second source", not under modern concepts. In the Mitra case we would thus say, here is no evidence that Röding would have used a different generic name, had he known that Lamarck had used it previously for a group of species containing Voluta mitra.
An example of a recently created confusion that would be avoided by such a provision, is the genus Bufo (Amphibia), established by Garsault 1764 for a French toad, without nominal species included, and used by Laurenti 1768 for German and Austrian toads. Dubois & Bour 2010 (Zootaxa 2447) argued that Garsault and Laurenti used Bufo for different taxa (because under modern concepts French and German/Austrian toads refer to slightly different species or subspecies), and that Bufo Laurenti, 1768 was a new name, not a subsequent use of Bufo Garsault, 1764. Such interpretations create conflicts, confusion and nomenclatural disputes, because such subsequent uses would be converted into new names at every instance when new taxonomic research comes to the conclusion that under modern concepts the first and the second author used the name in a different taxonomic sense. A clear provision in the Code as proposed above would expressly reject such an interpretation because the taxonomic judgement of Laurenti 1768 would be regarded as decisive for the decision "new name by Laurenti 1768 or not", which would quickly lead to the quite undisputable conclusion that Laurenti would certainly not have seen a reason to use a different name, had he known that Garsault 1764 had previously used the same name for a French toad.