{{Short description|Extinct genus of mammals}} {{Italic title}} {{Automatic taxobox | fossil_range = Santonian-Maastrichtian<br />~{{fossil range|84.9|70.6}} | image = Deltatheridium praetrituberculare.JPG | image_caption = ''Deltatheridium pretrituberculare'' | image2 = Deltatheridium DB24.jpg | image2_caption = Life restoration | taxon = Deltatheridium | authority = Gregory & Simpson, 1926 | subdivision_ranks = Species | subdivision = * ''D. pretrituberculare'' (type) * ''D. nessovi'' }}
'''''Deltatheridium''''' (meaning ''triangle beast'' or ''delta beast'') is an extinct species of metatherian. It lived in what is now Mongolia during the Upper Cretaceous, ''circa'' 80 million years ago.<ref>{{Cite web|url=https://www.sciencedaily.com/releases/1998/12/981203075716.htm|title=Discovery Of New Fossils In Gobi Desert Of Mongolia Provides Important Insight Into Early Mammal Evolution|website=Sciencedaily.com|access-date=30 November 2021}}</ref> A study in 2022 strongly suggested that ''Deltatheridium'' was a marsupial, making it the earliest known member of this group.<ref>{{cite journal |last1=Velazco |first1=Paúl M |last2=Buczek |first2=Alexandra J |last3=Hoffman |first3=Eva |last4=Hoffman |first4=Devin K |last5=O’Leary |first5=Maureen A |last6=Novacek |first6=Michael J |date=30 January 2022 |title=Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia |journal=Cladistics |volume=38 |issue=3 |pages=359–373 |doi=10.1111/cla.12499 |pmid=35098586 |url=https://discovery.ucl.ac.uk/id/eprint/10178921/ |url-access=subscription }}</ref>
It had a length of about {{convert|15|cm|in|abbr=on}}. Its teeth indicate it was carnivorous. One specimen of ''Archaeornithoides'' might attest to an attack by this mammal, the skull bearing tooth marks that match its teeth.<ref>Elżanowski, A. Wellnhoffer, P. (1993). "Skull of Archaeornithoides From the Upper Cretaceous of Mongolia". earth.geology.yale.edu/~ajs/1993/11.1993.08Elzanowski.pdf . American Journal of Science</ref>
== Other Mesozoic mammals from Mongolia == *''Kamptobaatar'' *''Zalambdalestes''
== References == {{Portal|Paleontology|Prehistoric mammals}} {{Reflist}}
== Further reading == * Parker, Steve. Dinosaurus: the complete guide to dinosaurs. Firefly Books Inc, 2003. Pg. 403 * {{cite journal |last=Rougier |first=G. W. |author2=Wible, J. R. |author3=Novacek, M. J. |year=1998 |title=Implications of ''Deltatheridium'' specimens for early marsupial history |journal=Nature |volume=396 |issue=6710 |pages=459–63 |doi=10.1038/24856 |pmid=9853752 |bibcode=1998Natur.396..459R |s2cid=204996216 }}
{{Metatheria|M.}} {{Taxonbar|from=Q903626}}
Category:Prehistoric metatherians Category:Prehistoric mammal genera Category:Santonian life Category:Campanian life Category:Late Cretaceous mammals of Asia Category:Fossils of Kazakhstan Category:Fossils of Mongolia Category:Djadochta fauna Category:Transitional fossils Category:Fossil taxa described in 1926
{{cretaceous-mammal-stub}}