Editing Koala (section)

===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'''''
                      }}
                   }}
                }}
             }}
          }}
       }}
    }}
 }}
}}

}}