Apus (bird)

Apus is a genus of birds in the family Apodidae. They are called swifts in English. Not all swifts are in genus "Apus", but all birds in "Apus" are swifts.
Taxonomy.
Italian naturalist Giovanni Antonio Scopoli made the genus "Apus" in 1777. He did it by looking at tautonymy and the common swift. Carl Linnaeus named the common swift "Hirundo apus" in 1758. The name "Apus" is Latin for a swift. The word is from Ancient Greek : α, "a", "without," and πούς, "pous", "foot." People thought they were swallows without feet.
Before the 1950s, scientists disagreed about which animals should have the name "Apus". In 1801, Bosc gave the small crustacean animals that we call "Triops" today the genus name "Apus," and later writers continued to use it for them. In 1909, Keilhack said this was incorrect because there was already a group of birds called "Apus". It was not until 1958 that the scientists in the International Commission on Zoological Nomenclature (ICZN) decided to use the name for only birds.
Species.
The genus has 20 species:
Some birds in "Apus" are dead. Scientists learned about them from fossils, marks that their bones left in rocks:
Scientists say the bird ""Apus" ignotus" is really in "Procypseloides".