Editing Emu (section)

===Systematics===
The emu was long classified, with its closest relatives the cassowaries, in the family [[Casuariidae]], part of the [[ratite]] order Struthioniformes.<ref name=Christidis>{{cite book|author1=Christidis, Les|author2=Boles, Walter|title=Systematics and Taxonomy of Australian Birds|url=https://books.google.com/books?id=SFP9P1i-PoEC&pg=PA57 |year=2008|publisher=Csiro Publishing |isbn=978-0-643-06511-6 |page=57}}</ref> An alternate classification was proposed in 2014 by Mitchell et al., based on analysis of [[mitochondrial DNA]]. This splits off the Casuariidae into their own order, the [[Casuariiformes]],<ref>{{cite book|author=Tudge, Colin|year=2009|title=The Bird: A Natural History of Who Birds Are, Where They Came From, and How They Live|page=[https://archive.org/details/birdnaturalhisto0000tudg/page/116 116]|publisher=Random House Digital|isbn=978-0-307-34204-1|url-access=registration|url=https://archive.org/details/birdnaturalhisto0000tudg/page/116}}</ref> and includes only the cassowaries in the family Casuariidae, placing the emus in their own family, [[Dromaiidae]]. The [[cladogram]] shown below is from their study.<ref name=Mitchell>{{cite journal |author1=Mitchell, K.J. |author2=Llamas, B. |author3=Soubrier, J. |author4=Rawlence, N.J. |author5=Worthy, T.H. |author6=Wood, J. |author7=Lee, M.S.Y. |author8=Cooper, A. |year=2014 |title=Ancient DNA reveals elephant birds and kiwi are sister taxa and clarifies ratite bird evolution |journal=Science |volume=344 |issue=6186 |pages=898–900 |doi=10.1126/Science.1251981 |pmid=24855267 |bibcode=2014Sci...344..898M |url=https://www.researchgate.net/publication/262562180 |hdl=2328/35953 |s2cid=206555952 |hdl-access=free }}</ref>
{{clade|style=font-size:85%; line-height:85%
|label1=Recent [[paleognath]]s
|1={{Clade
 |1={{Clade
  |1={{Clade
   |1={{Clade
    |1={{Clade
     |1=†[[Aepyornithidae]] (elephant birds)
     |2=[[Apterygidae]] (kiwi)
     }}
    |2={{Clade
     |1='''Dromaiidae''' ('''emus''')
     |2=[[Casuariidae]] (cassowaries)
     }}
    }}
   |2={{Clade
    |1=†[[Dinornithiformes]] (moa)
    |2=[[Tinamidae]] (tinamous)
    }}
   }}
  |2=[[Rheidae]] (rheas)
 }}
|2=[[Struthionidae]] (ostriches)
}}
}}

Two different ''Dromaius'' species were present in Australia at the time of European settlement, and one additional species is known from fossil remains. The [[insular dwarf]] emus, ''[[Kangaroo Island emu|D. n. baudinianus]]'' and ''[[King Island emu|D. n. minor]]'', originally present on [[Kangaroo Island]] and [[King Island (Tasmania)|King Island]] respectively, both became [[extinction|extinct]] shortly after the arrival of Europeans.<ref name="AM">{{cite web|author=Boles, Walter |publisher=Australian Museum |url=https://australian.museum/learn/animals/birds/emu/ |title=Emu |date=6 April 2010 |access-date=18 July 2015}}</ref><ref name=Heupink>{{cite journal|author1=Heupink, Tim H. |author2=Huynen, Leon |author3=Lambert, David M. | year=2011|title=Ancient DNA suggests dwarf and 'giant' emu are conspecific|journal=PLOS ONE|volume=6|issue=4 |page= e18728| doi=10.1371/journal.pone.0018728|pmid=21494561|pmc=3073985| bibcode=2011PLoSO...618728H|doi-access=free }}</ref> ''[[Tasmanian emu|D. n. diemenensis]]'', another insular dwarf emu from [[Tasmania]], became extinct around 1865. The mainland subspecies, ''D. n. novaehollandiae'', remains common. The population of these birds varies from decade to decade, largely being dependent on rainfall; in 2009, it was estimated that there were between 630,000 and 725,000 birds.<ref name=BirdLife/> Emus were introduced to [[Maria Island]]<ref name=Williams>{{cite book|author=Williams, W.D.|title=Biogeography and Ecology in Tasmania|url=https://books.google.com/books?id=Pp3qCAAAQBAJ&pg=PA450 |year=2012|publisher=Springer Science & Business Media |isbn=978-94-010-2337-5 |page=450 }}</ref> off Tasmania, and Kangaroo Island off the coast of South Australia, during the 20th century. The Maria Island population died out in the mid-1990s. The Kangaroo Island birds have successfully established a breeding population.<ref>{{cite book|author=Frith, Harold James|title=Wildlife conservation|url=https://books.google.com/books?id=RAsKAQAAMAAJ |year=1973 |publisher=Angus and Robertson |page=308|isbn=9780207126888}}</ref>

In 1912, the Australian ornithologist [[Gregory M. Mathews]] recognised three living subspecies of emu,<ref>{{cite journal |author=Mathews, Gregory M. |year=1912 |title=Class: Aves; Genus ''Dromiceius'' |journal=Novitates Zoologicae |volume=XVIII |issue=3 |pages=175–176 |url=https://www.biodiversitylibrary.org/item/22250#page/199/mode/1up }}</ref> ''D. n. novaehollandiae'' (Latham, 1790),<ref>{{cite web |url=http://avibase.bsc-eoc.org/species.jsp?lang=EN&avibaseid=C4C362A9&sec=summary&ssver=1 |title=Emu (South Eastern): ''Dromaius novaehollandiae [novaehollandiae'' or ''rothschildi''] (= ''Dromaius novaehollandiae novaehollandiae'') (Latham, 1790) |work=Avibase |access-date=5 September 2015}}</ref> ''D. n. woodwardi'' Mathews, 1912<ref>{{cite web |url=http://avibase.bsc-eoc.org/species.jsp?lang=EN&avibaseid=A789F41C&sec=summary&ssver=1 |title=Emu (Northern): ''Dromaius novaehollandiae novaehollandiae'' (woodwardi) (= ''Dromaius novaehollandiae woodwardi'') Mathews, 1912 |work=Avibase |access-date=5 September 2015}}</ref> and ''[[Rothschild's emu|D. n. rothschildi]]'' Mathews, 1912.<ref>{{cite web |url=http://avibase.bsc-eoc.org/species.jsp?lang=EN&avibaseid=AEA00567&sec=summary&ssver=1 |title=Emu (South Western): ''Dromaius novaehollandiae rothschildi'' Mathews, 1912 |work=Avibase |access-date=5 September 2015}}</ref> The [[Handbook of the Birds of the World]], however, argues that the last two of these subspecies are invalid; natural variations in plumage colour and the nomadic nature of the species make it likely that there is a single race in mainland Australia.<ref name=HBWA/><ref>{{cite web|url=http://www.worldbirdnames.org/updates/subspecies/ |title=Subspecies Updates |work=IOC World Bird List, v 5.2 |editor=Gill, Frank |editor2=Donsker, David |access-date=14 July 2015}}</ref> Examination of the DNA of the King Island emu shows this bird to be closely related to the mainland emu and hence best treated as a subspecies.<ref name=Heupink />