Editing Sugar glider (section)

==Taxonomy and evolution==
The genus ''[[Petaurus]]'' is believed to have originated in New Guinea during the mid [[Miocene]] epoch, approximately 18 to 24 million years ago. The modern Australian ''Petaurus'', along with New Guinean members of what were formerly considered ''P. breviceps'', diverged from their closest living New Guinean relatives ~9-12 mya. They probably dispersed from New Guinea to Australia between 4.8 and ~8.4 mya, with the oldest ''Petaurus'' fossils in Australia being dated to 4.46 million years.<ref name=Malekian(2010)>{{cite journal |last1=Malekian |first1=M |last2=Cooper |first2=S |last3=Norman |first3=J |last4=Christidis |first4=L |last5=Carthew |first5=S |title=Molecular systematics and evolutionary origins of the genus ''Petaurus'' (Marsupialia: Petauridae) in Australia and New Guinea |journal=Molecular Phylogenetics and Evolution |date=2010 |volume=54 |issue=1 |pages=122–135 |doi=10.1016/j.ympev.2009.07.026 |pmid=19647084}}</ref> This may have been possible due to sea level lowering from about 7 to 10 mya, resulting in land bridges between New Guinea and Australia.

The taxonomy of the species is complex, and is still not fully resolved. It was formerly understood to have a wide range across Australia and New Guinea, being the only [[Petaurus|glider]] to have this distribution, and to be divided into seven subspecies, with three occurring in Australia and four in New Guinea.<ref name="Malekian2">{{cite journal|last1=Malekian|first1=Mansoureh|last2=Cooper|first2=Steven J. B.|last3=Carthew|first3=Susan M.|date=2010|title=Phylogeography of the Australian sugar glider (''Petaurus breviceps''): evidence for a new divergent lineage in eastern Australia|journal=Australian Journal of Zoology|volume=58|issue=3|pages=165|doi=10.1071/ZO10016}}</ref> This traditional subspecific division was based on small [[Morphology (biology)|morphological]] differences, such as colour and body size.<ref name="Malekian(2010)" /> However, a 2010 genetic analysis using [[mitochondrial DNA]] indicates that these morphologically-defined subspecies may not represent genetically unique populations.<ref name="Malekian2" /> 

Further studies have found significant genetic variation within populations traditionally classified in ''P. breviceps'', sufficient to warrant splitting the species into multiple. The subspecies ''P. b. biacensis'', from [[Biak|Biak Island]] off of New Guinea, was reclassified as a separate species, the [[Biak glider]] (''Petaurus biacensis'').{{refn|group=note|name=Biak}} In 2020, a landmark study suggested that ''P. breviceps'' actually comprised three [[Species complex|cryptic species]]: the [[Krefft's glider]] (''Petaurus notatus''), found throughout most of eastern Australia and introduced to [[Tasmania]], the [[savanna glider]] (''Petaurus ariel''), native to northern Australia, and a more narrowly defined ''P. breviceps'', restricted to a small section of coastal forest in southern [[Queensland]] and most of [[New South Wales]]. In addition, other sugar glider populations throughout this range (such as those on [[New Guinea]] and the [[Cape York Peninsula]]) may represent undescribed species or be [[conspecific]] with previously described species. This indicates that contrary to previous findings of a large range (which in fact applied to ''P. notatus'' and, to a lesser extent, to ''P. ariel''), ''P. breviceps'' is a range-restricted species that is sensitive to ecological disasters, such as the [[2019–20 Australian bushfire season|2019-20 Australian bushfires]], which significantly affected large portions of its habitat.<ref name="ASM-PetBreviceps" /><ref name="Cremona-2020" /><ref>{{cite web|last1=Stobo-Wilson|first1=Alyson|last2=Baker|first2=Andrew|last3=Cooper|first3=Steve|last4=Carthew|first4=Sue|last5=Cremona|first5=Teigan|title=A rare discovery: we found the sugar glider is actually three species, but one is disappearing fast|url=http://theconversation.com/a-rare-discovery-we-found-the-sugar-glider-is-actually-three-species-but-one-is-disappearing-fast-142807|access-date=2020-07-17|website=The Conversation|date=16 July 2020 |language=en}}</ref>

''P. breviceps'' and ''P. notatus'' are estimated to have diverged ~1 million years ago, and may have [[Speciation|originated]] from long term geographic isolation. The early-mid [[Pleistocene]] saw an uplifting of the [[Great Dividing Range]], contributing to and coinciding with aridification of the interior of Australia, including on the western side of the range.<ref name=Malekian2 /> This, as well as other climactic and geographic factors, may have isolated the ancestors of ''P. breviceps'' to [[Refugium (population biology)|refugia]] on the eastern, coastal side of the Great Dividing Range.<ref name="ASM-PetBreviceps"/> This would be an example of [[allopatric speciation]].