A genus may be accessible or unavailable in zoology. The names provided are genus names that have been published according to the International Code of Zoological Nomenclature (ICZN) and the International Commission on Zoological Nomenclature’s criteria. The names that are not accessible are those that were not published due to noncompliance with the ICZN Code. Other factors include misspellings and a lack of type species. In botany, an available name is one that has been validly published, whereas an unavailable name is one that has not yet been published.
A label, nomen invalidum, is given to an invalid genus name (nom. Inval.). In botany, a valid name is referred to as a right name or current name. It’s possible that the genus name will change throughout time and be replaced by another. When new knowledge becomes available, something occurs. As a result, the previously approved term becomes a synonym. Catodon (Linnaeus, 1761), Cetus (Billberg, 1828), Meganeuron (Gray, 1865), Megistosaurus (Harlan, 1828), Phiseter (Bonnaterre, 1789), Physalus (Lacépède, 1804), Physeterus (Duméril, 1806), and Tursio are some of the synonyms for Physeter (Linnaeus (Fleming, 1822).
In biological taxonomy, a homonym is a name that is shared by two taxa. The ambrosia beetle and the platypus, for example, were given the genus name Platypus. Despite this, the ambrosia beetle was the first to be given the genus name Platypus, while the platypus was later given the name Ornithorhynchus. Because they are both from the Kingdom Animalia, they cannot have the same generic name. However, it is still discouraged to use the same genus for specimens from different kingdoms. There are hundreds of examples of species belonging to the same genus from different kingdoms. Aoutus, for example, is the genus name for both night monkeys and golden peas.