Editing Pink-headed duck (section)

==Taxonomy and systematics==
[[File:RhodonessaBhawaniDas.jpg|upright|thumb|left|Painting by Bhawani Das, of a living specimen in the collection of [[Mary Impey|Lady Impey]], circa 1777. This accurately records the colour of the legs.]]
The pink-headed duck was described by John Latham in 1790 under the genus ''Anas''.<ref>{{cite book| url=https://archive.org/stream/p1generalzoology10shawuoft#page/207/mode/1up/|pages=207–208|title=General Zoology. Volume 12 part 2. Aves|author=Stephens, J. F.|year=1824}}</ref><ref name=swainson /> In describing the species, it is possible that he made of use of a painting in the collection of [[Mary Impey|Lady Impey]], wife of Sir [[Elijah Impey]] who was Chief Justice of court in Calcutta from 1774 to 1783. Mary Impey maintained a menagerie in Calcutta and commissioned Indian artists such as Bhawani Das from Patna to illustrate animals in the collection. The Impeys moved to England, and after the death of her husband, she sold these paintings at auction in 1810. Some of them were acquired by the [[Edward Smith-Stanley, 13th Earl of Derby|13th Earl of Derby]].<ref>{{cite book|title=A Passion for Natural History: The Life and Legacy of the 13th Earl of Derby|year=2002|editor=Fisher, C. T.|publisher= National Museums and Galleries on Merseyside|isbn=1-902700-14-7}}</ref><ref>{{cite journal|last1=Fisher|first1=C.|last2=Kear|first2=J. |year=2002| title= The taxonomic importance of two early paintings of the pink-headed duck ''Rhodonessa caryophyllacea'' (Latham 1790)|journal= Bull. Brit. Orn. Club |volume=122|issue=4|pages=244–248|url=https://archive.org/details/bulletinofbritis122brit/page/244}}</ref>
[[File:SyrinxRhodonessaGarrod.jpg|thumb|The swelling at the base of trachea in the male]]
The genus ''Rhodonessa'' was originally created for this species alone. [[Jean Delacour]] and [[Ernst Mayr]], in their 1945 revision of the family Anatidae considered it a somewhat abnormal member of the ''Anatini'' (or river-ducks) group because the hind toe is slightly lobed, display behaviour and the tendency to feed at the surface. The birds were observed in European aviaries and although they never bred, the males displayed often and this involved puffing the neck feathers, lowering the neck to rest on the back and then stretching up the neck while producing a wheezy whistle like a [[mallard]].<ref>{{cite journal|author1=Delacour, Jean |author2=Mayr, Ernst |year= 1945| title=The Family Anatidae| journal= Wilson Bull.|volume=57|pages=3–55|url =https://sora.unm.edu/node/3253}}</ref> A study of its tracheal anatomy by [[Alfred Henry Garrod]] in 1875<ref>{{cite journal|author=Garrod, Alfred Henry |year=1875|title=On the form of the lower larynx in certain species of ducks|journal= Proc. Zool. Soc. London|pages=151–156|url=https://archive.org/stream/proceedingsofgen75zool#page/152/mode/2up/}}</ref> suggested that it had a "slight fusiform dilatation" in the anterior syringeal region. The "bulba ossea" at the lower part of the male syrinx is peculiar in being swollen. The colour pattern has also been considered unique, lacking any of the metallic colours on the secondaries that are characteristic of the Anatini. The other unique feature being the somewhat large and nearly spherical shape of the eggs. All of these features supporting the retention of the species in a separate genus.<ref name=fbi>{{cite book|title=The Fauna of British India, Including Ceylon and Burma. Birds. Volume 4|year=1898 |author=Blanford WT |publisher=Taylor and Francis, London|pages=425–426|url=https://archive.org/stream/birdsindia04oaterich#page/425/mode/1up/}}</ref> Such mid-tracheal swellings were found only in [[Mergini]] and [[Aythyini]] and is extremely rare in the genus ''[[Anas]]''. This tracheal bulla is rounded in ''Anas'' but angular with fenestrae in ''[[Netta]]'' and ''[[Aythya]]''. Johnsgard considered ''[[Marmaronetta]]'' and ''Rhodonessa'' as intermediate in form.<ref>{{cite journal|author=Johnsgard, Paul A.|author-link=Paul Johnsgard|title= The Taxonomy of the Anatidae: A behavioural analysis|journal=Ibis|volume=103|year=161|pages=71–85|url=http://digitalcommons.unl.edu/johnsgard/29/|doi= 10.1111/j.1474-919X.1961.tb02421.x|s2cid=35642972 |url-access=subscription}}</ref><ref>{{cite book|title=Handbook of Waterfowl Behavior|chapter=Tribe Aythyini (Pochards)|author=Johnsgard, Paul A.|author-link=Paul Johnsgard|year=1965|url=https://archive.org/details/handbookofwaterf00paul|publisher=Cornell University Press|location=Ithaca, New York|isbn=0-8014-0207-7}}</ref> Based on the available morphological and behavioural evidence, especially the structure of the [[humerus]]<ref>{{cite journal|author=Woolfenden, G. E.|year=1959| title=Postcranial osteology of the waterfowl|journal=Bull. Fla. State Mus.|volume=6|issue=1|pages=183–187|url=http://digitool.fcla.edu/R/CJSHCSLHP2G7FLJK6MDXIYRQYPJPD67LJ8IL853CK9R8HK7AHY-01180?func=dbin-jump-full&object_id=952786}}</ref> and the structure of [[Vertebrate trachea|tracheal]] rings, [[Sidney Dillon Ripley]] suggested that it was undoubtedly in the Aythyini.<ref name=ripley>{{cite journal|author1=Humphrey, P. S. |author2=Ripley, S. D. |year=1962|title= The affinities of the Pink-headed Duck (''Rhodonessa caryophyllacea'')|journal=Postilla |volume=61|pages=1–21|url=https://archive.org/details/postilla611962peab }}</ref>

A study found that ''Rhodonessa'' was closely allied to the [[red-crested pochard]] (''Netta rufina'') suggesting that the two species be placed in the same genus.<ref>{{cite journal|author=Livezey, B. C. |year=1998|title=A phylogenetic analysis of modern pochards (Anatidae: Aythini)|journal=The Auk|volume=113|issue=1|pages= 74–93|url=http://sora.unm.edu/sites/default/files/journals/auk/v113n01/p0074-p0093.pdf|doi=10.2307/4088937|jstor=4088937}}</ref> ''Rhodonessa'' was described prior to ''Netta'' which would then make ''Rhodonessa rufina'' the name of choice, however these changes have not been widely accepted.<ref>{{cite book |editor1=Collar, N. J. |editor2=Andreev, A. V. |editor3=Chan, S. |editor4=Crosby, M. J. |editor5=Subramanya, S. |editor6=Tobias, J. A. |year=2001 |chapter=Pink-headed Duck |title=Threatened Birds of Asia: The BirdLife International Red Data Book |pages=489–501 |publisher=BirdLife International |isbn=0-946888-44-2 |url=http://birdbase.hokkaido-ies.go.jp/rdb/rdb_en/rhodcary.pdf |access-date=2010-04-30 |archive-date=2012-03-06 |archive-url=https://web.archive.org/web/20120306020347/http://birdbase.hokkaido-ies.go.jp/rdb/rdb_en/rhodcary.pdf |url-status=dead }}</ref> The pink colour is derived from a carotenoid pigment which is unusual among ducks and known only from a few other species such as the [[pink-eared duck]] which are not closely related.<ref>{{Cite journal|last1=Thomas|first1=Daniel B.|last2=James|first2=Helen F.|date=2016|title=Nondestructive Raman spectroscopy confirms carotenoid-pigmented plumage in the Pink-headed Duck|url=https://repository.si.edu/bitstream/handle/10088/28050/Thomas-16-Auk-pink-headed%20duck.pdf?sequence=1&isAllowed=y|journal=The Auk|language=en|volume=133|issue=2|pages=147–154|doi=10.1642/AUK-15-152.1|s2cid=54210463|issn=0004-8038|doi-access=free}}</ref>