The platypus lost its own name because a beetle got there first
George Shaw named the platypus Platypus in 1799, but a group of ambrosia beetles already had that genus name from 1793. Since both are animals, the name could not be shared, and the duck-billed mammal became Ornithorhynchus. Such clashes reveal how the genus, the first half of every scientific name, actually works.
A genus sits above species and below family. In a name like Panthera leo, the lion, Panthera marks the genus it shares with the jaguar, Panthera onca. The gray wolf is Canis lupus, Latin for dog and wolf. The generic name is always capitalised and italicised, and once it is clear from context it can shrink to an initial, as in C. lupus. The idea is usually credited to the French botanist Joseph Pitton de Tournefort, and Carl Linnaeus spread it with his 1753 Species Plantarum.
There is no strict rulebook for drawing genus boundaries, so experts often disagree. Common guidelines are that a genus should include all descendants of a shared ancestor, should not be inflated needlessly, and should be distinct in ecology, form or geography. Each genus is supposed to be anchored to a type species; if that type turns out to belong elsewhere, the name becomes a junior synonym.
Duplicate names within one kingdom are forbidden, but across kingdoms governed by different codes they slip through; roughly five thousand names are used in more than one. Aotus means both golden peas and night monkeys, and Prunella is both a songbird and the plant self-heal. The sperm whale genus alone has eight recorded synonyms.
Nobody knows exactly how many genera exist. A 2020 study estimated around 310,000 accepted names out of about 520,000 published by the end of 2019, with roughly 2,500 new generic names appearing every year. Animals account for the lion's share.
Source: Genus
