Editing Koala (section)

==Taxonomy==
The generic name ''Phascolarctos'' was given in 1816 by French zoologist [[Henri Marie Ducrotay de&nbsp;Blainville]],<ref>{{cite journal |author=de Blainville, H. |title=Prodrome d'une nouvelle distribution systématique du règne animal |journal=Bulletin de la Société Philomáthique, Paris |year=1816 |volume=8 |pages=105–24 |language=fr |url=https://www.biodiversitylibrary.org/page/4439803 |access-date=20 February 2018 |archive-url=https://web.archive.org/web/20181014145245/https://www.biodiversitylibrary.org/page/4439803 |archive-date=14 October 2018 |url-status=dead }}</ref> who did not give it a specific name until further review. In 1819, German zoologist [[Georg August Goldfuss]] gave it the [[Binomial nomenclature|binomial]] ''Lipurus cinereus''. Because ''Phascolarctos'' was published first, according to the [[International Code of Zoological Nomenclature]], it has [[Principle of Priority|priority]] as the official genus name.<ref name=jackson>{{cite book |author=Jackson, S. |year=2010 |title=Koala: Origins of an Icon |publisher=Allen & Unwin |edition=2nd |isbn=978-1-74237-323-2 |url={{google books|plainurl=yes|id=uAic9hHaB1IC}}|access-date=9 November 2015 |archive-date=3 February 2021 |archive-url=https://web.archive.org/web/20210203083713/https://books.google.com/books?id=uAic9hHaB1IC |url-status=live }}</ref>{{rp|58–59}} French naturalist [[Anselme Gaëtan Desmarest]] coined the name ''Phascolarctos fuscus'' in 1820, suggesting that the brown-coloured versions were a different species than the grey ones. Other names suggested by European authors included ''Marodactylus cinereus'' by Goldfuss in 1820, ''P.&nbsp;flindersii'' by [[René Primevère Lesson]] in 1827, and ''P.&nbsp;koala'' by [[John Edward Gray]] in 1827.<ref name=moyal>{{cite book | last=Moyal | first=Ann | title=Koala: a historical biography | publisher=CSIRO Pub | publication-place=Melbourne | year=2008 | isbn=978-0-643-09401-7 | oclc=476194354 | url={{google books|plainurl=yes|id=QGT47L1cbLIC}}| access-date=9 November 2015 | archive-date=2 May 2016 | archive-url=https://web.archive.org/web/20160502165906/https://books.google.com/books?id=QGT47L1cbLIC | url-status=live }}</ref>{{rp|45}}

===Evolution===
The koala is classified with [[wombat]]s (family ''[[Vombatidae]]'') and several extinct families (including [[Palorchestes|marsupial tapirs]], [[Thylacoleonidae|marsupial lions]] and [[Diprotodontidae|giant wombats]]) in the suborder [[Vombatiformes]] within the order [[Diprotodontia]].<ref name="Long">{{cite book|author=Long, J. A.|year=2002|title=Prehistoric Mammals of Australia and New Guinea: One Hundred Million Years of Evolution|publisher=Johns Hopkins University Press|pages=77–82|isbn=978-0-8018-7223-5}}</ref> The Vombatiformes are a [[sister group]] to a [[clade]] that includes [[Macropodiformes|macropods]] (kangaroos and [[Wallaby|wallabies]]) and [[Phalangeriformes|possums]].<ref>{{cite journal|author1=Asher, R. |author2=Horovitz, I. |author3=Sánchez-Villagra, M. |year=2004|title=First combined cladistic analysis of marsupial mammal interrelationships|journal=Molecular Phylogenetics and Evolution|volume=33|issue=1|pages=240–50|doi=10.1016/j.ympev.2004.05.004|pmid=15324852|bibcode=2004MolPE..33..240A }}</ref> The koala's lineage possibly branched off around 40&nbsp;million years ago during the [[Eocene]].<ref>{{cite journal|author=Beck, R. M. D.|year=2008|title=A dated phylogeny of marsupials using a molecular supermatrix and multiple fossil constraints|journal=Journal of Mammalogy|volume=89|issue=1|pages=175–89|doi=10.1644/06-MAMM-A-437.1|doi-access=free}}</ref>
[[File:Nimiokoala Litokoala.JPG|thumb|right|upright|Reconstructions of the ancient koalas ''Nimiokoala'' (larger), and ''Litokoala'' (smaller), from the Miocene Riversleigh Fauna]]
The modern koala is the only [[Extant taxon|extant]] member of ''[[Phascolarctidae]]'', a family that includes several extinct genera and species. During the [[Oligocene]] and [[Miocene]], koalas lived in rainforests and had broader diets.<ref name=Louysa>{{cite journal|author1=Louys, J. |author2=Aplin, K. |author3=Beck, R. M. D. |author4=Archer, M. |year=2009|title=Cranial anatomy of Oligo-Miocene koalas (Diprotodontia: Phascolarctidae): Stages in the evolution of an extreme leaf-eating specialization|journal=Journal of Vertebrate Paleontology|volume=29|issue=4|pages=981–92|doi=10.1671/039.029.0412|bibcode=2009JVPal..29..981L |s2cid=86356713 |doi-access=free}}</ref> Some species, such as ''Nimiokoala greystanesi'' and some species of ''[[Perikoala]]'', were around the same size as the modern koala, while others, such as species of ''[[Litokoala]]'', were one-half to two-thirds its size.<ref name="Archer">{{cite journal |author1=Archer, M. |author2=Arena, R. |author3=Bassarova, M. |author4=Black, K. |author5=Brammall, J. |author6=Cooke, B. M. |author7=Creaser, P |author8=Crosby, K. |author9=Gillespie, A. |author10=Godthelp, H. |author11=Gott, M. |author12=Hand, S. J. |author13=Kear, B. P. |author14=Krikmann, A. |author15=Mackness, B. |author16=Muirhead, J. |author17=Musser, A. |author18=Myers, T. |author19=Pledge, N. S. |author20=Wang, Y. |author21=Wroe, S. |year=1999 |title=The evolutionary history and diversity of Australian mammals |journal=Australian Mammalogy |volume=21 |pages=1–45 |doi=10.1071/AM99001 |url=https://www.academia.edu/1157777 |access-date=1 November 2017 |archive-date=12 August 2021 |archive-url=https://web.archive.org/web/20210812194648/https://www.academia.edu/1157777 |url-status=live }}</ref> Like the modern species, prehistoric koalas had well developed ear structures, which suggests that they also made long-distance vocalisations and had a relatively inactive lifestyle.<ref name=Louysa/> During the Miocene, the Australian continent began drying out, leading to the decline of rainforests and the spread of open ''[[Eucalyptus]]'' woodlands. The genus ''Phascolarctos'' split from ''Litokoala'' in the late Miocene,<ref name=Louysa/><ref>{{cite journal|author1=Black, K. |author2=Archer, M. |author3=Hand, S. J. |year=2012|title=New Tertiary koala (Marsupialia, Phascolarctidae) from Riversleigh, Australia, with a revision of phascolarctid phylogenetics, paleoecology, and paleobiodiversity|journal=Journal of Vertebrate Paleontology|volume=32|issue=1|pages=125–38|doi=10.1080/02724634.2012.626825|bibcode=2012JVPal..32..125B |s2cid=86152273 }}</ref> and had several adaptations that allowed it to live on a eucalyptus diet: the [[palate]] shifted towards the front of the skull; the upper teeth were lined by thicker bone, molars became relatively low compared to the jaw joint and with more chewing surface; the [[pterygoid fossa]] shrank;<ref name=Louysa/> and a larger [[diastema (dentistry)|gap]] separated the [[incisor]] teeth and the molars.<ref name="Tyndale-Biscoe"/>{{rp|226}}

''P. cinereus'' may have emerged as a dwarf form of the [[giant koala]] (''P.&nbsp;stirtoni''), following the disappearance of several giant animals in the late [[Pleistocene]]. A 2008 study questioned this hypothesis, noting that ''P.&nbsp;cinereus'' and ''P.&nbsp;stirtoni'' were [[Sympatry|sympatric]] during the mid-late Pleistocene, and that their teeth morphology displayed the major differences.<ref>{{cite journal|author=Price, G. J.|year=2008|title=Is the modern koala (''Phascolarctos cinereus'') a derived dwarf of a Pleistocene giant? Implications for testing megafauna extinction hypotheses|journal=Quaternary Science Reviews|volume=27|issue=27–28|pages=2516–21|doi=10.1016/j.quascirev.2008.08.026|bibcode=2008QSRv...27.2516P|url=https://www.academia.edu/1299583|access-date=1 November 2017|archive-date=13 August 2021|archive-url=https://web.archive.org/web/20210813040512/https://www.academia.edu/1299583|url-status=live}}</ref> The fossil record of the modern koala extends back at least to the middle Pleistocene.<ref name="Price 2012">{{cite book |author=Price, G. J. |chapter=Long-term trends in lineage 'health' of the Australian koala (Mammalia: Phascolarctidae): Using paleo-diversity to prioritize species for conservation |title=Paleontology in Ecology and Conservation |series=Springer Earth System Sciences |editor-last=Louys, J. |year=2013 |publisher=Springer |pages=171–92 |isbn=978-3-642-25037-8}}</ref>

{{clade gallery |style=border:0; |headerstyle=width:325px;height:60px;vertical-align:top;
|header1=Molecular relationship between living Diprotodontia families based on Phillips and collages (2023)<ref>{{cite journal|last1=Phillips|first1=M. J.|last2=Celik|first2=M. A.|last3=Beck|first3=Robin M. D.|year=2023|title=The evolutionary relationships of Diprotodontia and improving the accuracy of phylogenetic inference from morphological data|journal=Alcheringa: An Australasian Journal of Palaeontology|volume=47 |issue=4 |pages=686–698 |doi=10.1080/03115518.2023.2184492|s2cid=257634430 |doi-access=free|bibcode=2023Alch...47..686P }}</ref> 
|cladogram1= 
{{clade
|1={{clade
   |1={{clade
      |1=[[Vombatidae]] (wombats)
      |2=[[Phascolarctidae]] (koalas)
    }}
   |2={{clade
      |1={{clade
         |1=[[Acrobatidae]]
         |2={{clade
            |1=[[Tarsipedidae]] (honey possum)
            |2={{clade
               |1=[[Petauridae]] ([[wrist-winged glider]]s and allies)
               |2=[[Pseudocheiridae]] (ringtail possums and allies)
             }}
          }}
       }}
      |2={{clade
         |1=[[Macropodidae]] (kangaroos, wallabies and allies)
         |2={{clade
            |1=[[Phalangeridae]] ([[brushtail possum]]s and [[cuscus]]es)
            |2=[[Burramyidae]] (pygmy possums)
          }}
       }}
    }}
 }}
}}

|header2=Morphology tree of Phascolarctidae based on Beck and collages (2020)<ref name=Beck2020>{{cite journal|first1=R. M. D.|last1=Beck|first2=J.|last2=Louys|first3=P.|last3=Brewer|first4=M.|last4=Archer|first5=K. H.|last5=Black|first6=R. H.|last6=Tedford|year=2020|title=A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes)|journal=Scientific Reports|volume=10|issue=9741|page=9741 |doi=10.1038/s41598-020-66425-8|pmid=32587406 |pmc=7316786 |bibcode=2020NatSR..10.9741B }}</ref>
|cladogram2=
{{clade
|1={{clade
   |1=[[Thylacoleonidae]] (extinct marsupial lion and allies)
   |2={{clade
      |1=[[Vombatomorphia]] (wombats and fossil relatives)
      |2={{clade
         |label1=[[Phascolarctidae]]
         |1={{clade
            |1=''[[Priscakoala]] lucyturnbullae''
            |2={{clade
               |1={{clade
                  |1=''[[Madakoala]]'' spp.
                  |2=''[[Perikoala]] robustus''
                }}
               |2={{clade
                  |1=''[[Nimiokoala]] greystanesi''
                  |2={{clade
                     |1=''[[Litokoala]] dicksmithi''
                     |2={{clade
                        |1=''Litokoala kutjamarpensis''
                        |2='''''Phascolarctos cinereus'''''
                      }}
                   }}
                }}
             }}
          }}
       }}
    }}
 }}
}}

}}

===Genetics and variations===
Three subspecies have been described: the Queensland koala (''Phascolarctos cinereus adustus'', [[Oldfield Thomas|Thomas]] 1923), the New South Wales koala (''Phascolarctos cinereus cinereus'', Goldfuss 1817), and the Victorian koala (''Phascolarctos cinereus victor'', [[Ellis Le Geyt Troughton|Troughton]] 1935). These forms are distinguished by [[pelage]] colour and thickness, body size, and skull shape. The Queensland koala is the smallest, with silver or grey short hairs and a shorter skull. The Victorian koala is the largest, with shaggier, brown fur and a wider skull.<ref name="Martin-Handasyde">{{cite book |author1=Martin, R. W. |author2=Handasyde, K. A. |year=1999 |title=The Koala: Natural History, Conservation and Management |publisher=New South Wales University Press |edition=2nd |isbn=978-1-57524-136-4 |url={{google books|plainurl=yes|id=RdWg_f5UI7cC}} |access-date=9 November 2015 |archive-date=6 April 2015 |archive-url=https://web.archive.org/web/20150406041539/http://books.google.com/books?id=RdWg_f5UI7cC |url-status=live }}</ref>{{rp|7}}<ref name="Houlden 1999">{{cite journal|author1=Houlden, B. A. |author2=Costello, B. H. |author3=Sharkey, D. |author4=Fowler, E. V. |author5=Melzer, A. |author6=Ellis, W. |author7=Carrick, F. |author8=Baverstock, P. R. |author9=Elphinstone, M. S. |year=1999|title=Phylogeographic differentiation in the mitochondrial control region in the koala, ''Phascolarctos cinereus'' (Goldfuss 1817)|journal=Molecular Ecology|volume=8|issue=6|pages=999–1011|doi=10.1046/j.1365-294x.1999.00656.x|pmid=10434420|bibcode=1999MolEc...8..999H |s2cid=36771770 }}</ref> The geographic limits of these variations are based on [[States and territories of Australia|state borders]], and their status as subspecies is disputed. A 1999 genetic study suggests koalas exist as a [[cline (biology)|cline]] within a single [[evolutionarily significant unit]] with limited [[gene flow]] between local populations.<ref name="Houlden 1999"/> In 2016, a comprehensive phylogenetic study did not support the recognition of any subspecies.<ref>{{Cite journal |last1=Neaves |first1=Linda E. |last2=Frankham |first2=Greta J. |last3=Dennison |first3=Siobhan |last4=FitzGibbon |first4=Sean |last5=Flannagan |first5=Cheyne |last6=Gillett |first6=Amber |last7=Hynes |first7=Emily |last8=Handasyde |first8=Kathrine |last9=Helgen |first9=Kristofer M. |last10=Tsangaras |first10=Kyriakos |last11=Greenwood |first11=Alex D. |last12=Eldridge |first12=Mark D. B. |last13=Johnson |first13=Rebecca N. |date=2 September 2016 |title=Phylogeography of the Koala, (Phascolarctos cinereus), and Harmonising Data to Inform Conservation |journal=PLOS ONE |language=en |volume=11 |issue=9 |pages=e0162207 |doi=10.1371/journal.pone.0162207 |issn=1932-6203 |pmc=5010259 |pmid=27588685 |doi-access=free|bibcode=2016PLoSO..1162207N }}</ref>

Other studies have found that koala populations are highly inbred with low [[genetic variation]].<ref>{{cite journal|author1=Houlden, B. A. |author2=England, P. R. |author3=Taylor A. C. |author4=Greville, W. D. |author5=Sherwin, W. B. |year=1996|title=Low genetic variability of the koala ''Phascolarctos cinereus'' in south-eastern Australia following a severe population bottleneck|journal=Molecular Ecology|volume=5|issue=2|pages=269–81|pmid=8673272|doi=10.1046/j.1365-294x.1996.00089.x |bibcode=1996MolEc...5..269H |s2cid=22441918 }}</ref><ref>{{cite journal|author1=Wilmer, J. M. W. |author2=Melzer, A. |author3=Carrick, F. |author4=Moritz, C. |year=1993|title=Low genetic diversity and inbreeding depression in Queensland Koalas|journal=Wildlife Research|volume=20|issue=2|pages=177–87|doi=10.1071/WR9930177}}</ref> Such low [[genetic diversity]] may have been caused by population declines during the late Pleistocene.<ref>{{cite journal|author1=Tsangaras, K. |author2=Ávila-Arcos, M. C. |author3=Ishida, Y. |author4=Helgen, K. M. |author5=Roca, A. L. |author6=Greenwood, A. D. |year=2012|title=Historically low mitochondrial DNA diversity in koalas (''Phascolarctos cinereus'')|journal=BMC Genetics|volume=13|pages=92|doi=10.1186/1471-2156-13-92|pmid=23095716|pmc=3518249|issue=1 |doi-access=free }}</ref> Rivers and roads limit gene flow and contribute to the isolation of southeast Queensland populations.<ref>{{cite journal |author1=Lee, K. E. |author2=Seddon, J. M. |author3=Corley, S. |author4=Williams, E. |author5=Johnston, S. |author6=Villers, D. |author7=Preece, H. |author8=Carrick, F. |year=2010 |title=Genetic variation and structuring in the threatened koala populations of Southeast Queensland |journal=Conservation Genetics |volume=11 |issue=6 |pages=2091–103 |doi=10.1007/s10592-009-9987-9|bibcode=2010ConG...11.2091L |s2cid=36855057 }}</ref> In April 2013, scientists from the [[Australian Museum]] and [[Queensland University of Technology]] announced they had [[Whole genome sequencing|fully sequenced]] the koala [[genome]].<ref name="Davey2013">{{cite news |title=Australians crack the code of koala's genetic blueprint |url=http://www.theage.com.au/national/australians-crack-the-code-of-koalas-genetic-blueprint-20130409-2hjfm.html |date=10 April 2013 |author=Davey, M. |newspaper=[[The Age]] |access-date=25 June 2013 |archive-url=https://web.archive.org/web/20130514133101/http://www.theage.com.au/national/australians-crack-the-code-of-koalas-genetic-blueprint-20130409-2hjfm.html |archive-date=14 May 2013 |url-status=live }}</ref>