australidelphia

{{Short description|Superorder of marsupials}}

{{Automatic taxobox

| fossil_range = {{fossilrange|61.6|0|earliest=Paleocene}} Early Paleocene to present{{Cite web|title=PBDB|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=99550&is_real_user=1|access-date=2021-07-13|website=paleobiodb.org}}

| image = Sumpfwallabycele4.jpg

| image_caption = A swamp wallaby

| taxon = Australidelphia

| authority = Szalay 1982

| subdivision_ranks = Orders

| subdivision = * Microbiotheria

• †Polydolopimorphia?
• Eomarsupialia
  {{Small|Archer, 1984}}{{cite journal |last1=Beck |first1=R. M. D. |last2=Travouillon |first2=K. J. |last3=Aplin |first3=K. P. |last4=Godthelp |first4=H. |last5=Archer |first5=M. |title=The Osteology and Systematics of the Enigmatic Australian Oligo-Miocene Metatherian Yalkaparidon (Yalkaparidontidae; Yalkaparidontia; ?Australidelphia; Marsupialia) |journal=Journal of Mammalian Evolution |date=2014 |volume=21 |issue=2 |pages=127–172 |doi=10.1007/s10914-013-9236-3|s2cid=18490996 |url=https://usir.salford.ac.uk/id/eprint/33350/1/Beck_et_al_%282014%29_Yalkaparidon.pdf }}
• Diprotodontia
• Agreodontia
  {{Small|Beck et al., 2014}}
• Dasyuromorphia
• Notoryctemorphia
• Peramelemorphia

}}

Australidelphia is a superorder of marsupials encompassing about three-quarters of all living marsupial species, including all those native to Australasia and one South American species, the monito del monte. Unlike other American marsupials, which belong to the Ameridelphia, Australidelphia’s lineage emerged in South America, with genetic evidence (retrotransposon insertion sites) showing the monito del monte as its most ancient branch.{{Cite web |last=Schiewe |first=Jessie |date=2010-07-28 |title=Australia's marsupials originated in what is now South America, study says |url=http://www.latimes.com/news/science/la-sci-marsupial-20100728,0,5549873.story |url-status=live |archive-url=https://web.archive.org/web/20100801001045/http://www.latimes.com/news/science/la-sci-marsupial-20100728%2C0%2C5549873.story |archive-date=1 August 2010 |access-date=2010-08-01 |work=Los Angeles Times}}{{Cite journal |last1=Nilsson |first1=M. A. |last2=Churakov |first2=G. |last3=Sommer |first3=M. |last4=Van Tran |first4=N. |last5=Zemann |first5=A. |last6=Brosius |first6=J. |last7=Schmitz |first7=J. |date=2010-07-27 |editor1-last=Penny |editor1-first=David |title=Tracking Marsupial Evolution Using Archaic Genomic Retroposon Insertions |journal=PLOS Biology |volume=8 |issue=7 |pages=e1000436 |doi=10.1371/journal.pbio.1000436 |pmc=2910653 |pmid=20668664 |doi-access=free}}

Within this superorder, the Australian members form a distinct group (clade) named Eomarsupialia, though their internal relationships (branching order) is yet to be determined. Studies suggest Australidelphia originated in South America alongside other major marsupial groups, likely dispersing to Australia via Antarctica in a single event after the monito’s lineage (Microbiotheria) diverged, leaving other South American orders (Didelphimorphia and Paucituberculata) as more basal.