Psittacula
Members of the parrot genus Psittacula or Afro-Asian ring-necked parrots they are commonly known in aviculture originate from Africa to South-East Asia. It is a widespread group with a clear concentration of species in south Asia, but also with representatives in Africa and the islands of the Indian Ocean. This is the only genus of Parrot which has the majority of its species in continental Asia. Of all the extant species only "Psittacula calthropae", "Psittacula caniceps" and "Psittacula echo" do not have a representative subspecies in any part of mainland continental Asia. The rose-ringed parakeet , "Psittacula krameri", is one of the most widely distributed of all parrots. The other two Asian genera, "Loriculus" and "Psittinus" are represented by only two species each, which occur in the mainland part of Asia. The majority of the "Loriculus" species occur on islands. Moreover, since "Loriculus" is spread across both sides of the Wallace Line it can be considered more Australasian than Asian. These parrots mostly have green plumage, with adults having coloured heads. The bill is stout, and the tail is long and graduated. Etymology. The genus name Psittacula is a diminutive of the Latin word psittacus meaning  parrot Taxonomy. The genus "Psittacula" was introduced in 1800 by the French naturalist Georges Cuvier. The type species was designated in 1923 by Gregory Mathews as the red-breasted parakeet. The name of the genus is a diminutive of the Latin word "psittacus" for a "parrot". The genus includes 16 species, of which three are extinct. Alternative taxonomy. Genetic evidence has found that the genus "Psittacula" is likely paraphyletic; for example, genetic analysis has supported merging short-tailed parrots of the genus "Tanygnathus," "Psittinus," and the extinct "Mascarinus" with "Psittacula." A revised classification was proposed by Michael Braun and coworkers  in 2019 that splits the genus "Psittacula" into multiple monophyletic genera in order to preserve "Tanygnathus, Psittinus," and "Mascarinus" as distinct genera. After the proposed split, the only remaining species in "Psittacula sensu stricto" are "P. derbiana", "P. caniceps", and "P. alexandri". This is also the taxonomic system followed by the IUCN Red List and BirdLife International. The list of split or monophyletic genera and species (and any of their allied species) is displayed below: The extinct Mascarene grey parrot("P. bensoni") was not sampled in the study and has not been reclassified to "Psittacula sensu lato" by the IUCN or  BirdLife, so it is still classified in "Lophopsittacus" under this taxonomy. The Nicobar parrot("P. caniceps") was also not sampled but kept in "Psittacula" by the authorities that incorporated this taxonomy. The study has also found that the rose-ringed and red-breasted parrots are likely paraphyletic species themselves, and thus need to be split into multiple species. Hypothetical extinct species. The Rothschild's or intermediate parakeet "P. intermedia", found in northern India, was formerly considered a mystery, as only very few specimens were known. It has since been demonstrated to be a hybrid between the slaty-headed parrot "P. himalayana  and the plum-headed parrot P. cyanocephala". The taxonomy of the Réunion parrot "P. eques" is also confusing. Extinct since 1770, little evidence even exists of the bird's existence. A study skin had been discovered at the Royal Museum of Scotland, explicitly referencing a book description of the Réunion birds. It is known from other descriptions, as well as illustrations of which it is unknown whether they were drawn from live or stuffed specimens. This may be the only material proof of these birds' existence. Taxonomists are unsure if the birds were a distinct species, or conspecific with the  Mauritius parrot, although genetic analysis supports it being a subspecies of the Mauritius parrot.