Editing Cockatiel (section)

== Taxonomy and etymology ==
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Originally described by J. F. Gmelin in an edition of Systema naturae in 1788 as ''Psittacus novaehollandiae'', and after by Scottish writer and naturalist [[Robert Kerr (writer)|Robert Kerr]] in 1792 as ''Psittacus hollandicus'', and finally moved to its own genus, ''Nymphicus'', by [[Johann Georg Wagler|Wagler]] in 1832.<ref>{{cite book | vauthors=((Linné,  Carl von)), ((Gmelin,  Johann Friedrich)), ((Beer,  Georg Emanuel.)) | date= 1788 | title=Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | publisher=Impensis Georg. Emanuel. Beer | volume=1 | url=https://www.biodiversitylibrary.org/page/2896928}}</ref><ref>{{cite book | vauthors=((Linné,  Carl von)), ((Gmelin,  Johann Friedrich)), ((Kerr,  Robert)), ((Archer,  J.)) | date= 1792 | title=The animal kingdom, or zoological system, of the celebrated Sir Charles Linnæus. containing a complete systematic description, arrangement, and nomenclature, of all the known species and varieties of the mammalia, or animals which give suck to their young | publisher=Printed for A. Strahan, and T. Cadell, London, and W. Creech, Edinburgh | url=https://www.biodiversitylibrary.org/page/38664580}}</ref><ref>{{cite book | vauthors=((Wagler,  Johann Georg)) | date= 1832 | title=Monographia Psittacorum | publisher=s.n | url=https://www.biodiversitylibrary.org/page/35991466}}</ref> Its genus name reflects the experience of one of the earliest groups of [[Europe]]ans to see the birds in their native [[habitat (ecology)|habitat]]; the travellers thought the birds were so beautiful that they named them after mythical [[nymphs]]. The [[specific name (zoology)|specific name]] ''hollandicus'' refers to [[New Holland (Australia)|New Holland]], a historical name for Australia.

Its biological relationships were for a long time uncertain; it is now placed in a [[monotypic]] [[subfamily]] Nymphicinae, but was sometimes in the past classified among the [[Platycercinae]], the broad-tailed parrots. This issue was settled with molecular studies. A 1984 study of protein allozymes signalled its closer relationship to cockatoos than to other parrots,<ref name=adams1984>{{cite journal|year=1984|title=Biochemical systematics of the Australian cockatoos (Psittaciformes: Cacatuinae)|journal=Australian Journal of Zoology |volume=32|issue=3|pages=363–77|doi=10.1071/ZO9840363|last1=Adams|first1= M|last2=Baverstock|first2=PR|last3=Saunders|first3=DA|last4=Schodde|first4=R|last5=Smith|first5=GT}}</ref> and [[mtDNA|mitochondrial]] 12S [[rRNA]] [[DNA sequence|sequence]] data<ref>Brown, D.M. & Toft, C.A. (1999): [https://www.academia.edu/364859/Molecular_Systematics_and_Biogeography_of_the_Cockatoos_Psittaciformes_Cacatuidae_ Molecular systematics and biogeography of the cockatoos (Psittaciformes: ''Cacatuidae'')]. Auk 116(1): 141-157. {{JSTOR|4089461}}</ref> places it among the [[Calyptorhynchinae]] (dark cockatoos) [[subfamily]]. The unique, [[parakeet]] (meaning long-tailed parrot) morphological feature is a consequence of the decrease in size and accompanying change of [[ecological niche]].

Sequence analysis of [[intron]] 7 of the [[nuclear DNA|nuclear]] ''β''-[[fibrinogen]] gene, on the other hand, indicates that it may yet be distinct enough as to warrant recognition of the Nymphicinae rather than inclusion of the genus in the [[Calyptorhynchinae]].<ref>Astuti, Dwi (2004): [http://www.ees.hokudai.ac.jp/coe21/J/study/17RA/dwi.pdf A phylogeny of Cockatoos (Aves: Psittaciformes) inferred from DNA sequences of the seventh intron of Nuclear β-fibrinogen gene]. Doctoral work, Graduate School of Environmental Earth Science, Hokkaido University, Japan.</ref>

The cockatiel is now biologically classified as a genuine member of [[Cacatuidae]] on account of sharing all of the cockatoo family's biological features, namely, the erectile crest, a [[gallbladder]], [[powder down]], suppressed cloudy-layer (which precludes the display of blue and green structural colours), and facial feathers covering the sides of the beak, all of which are rarely found outside the family Cacatuidae.  This biological relation to other cockatoos is further supported by the existence of at least one documented case of a successful [[hybrid (biology)|hybrid]] between a cockatiel and a [[galah]], another cockatoo species.<ref>{{Cite web|url=https://www.talkingbirds.com.au/world-firsts/galatiel-php/world-first-galah-breeds-with-cockatiel|title = Talking Birds}}</ref>