Deltatheroida

Deltatheroida; Temporal range: Early Cretaceous-Paleocene
	Sulestes reconstruction
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Metatheria
Order:	†Deltatheroida; Gregory and Simpson, 1926
Families and genera
	Pappotheriidae Pappotherium; ; Deltatheridiidae Atokatheridium; Deltatheridium; Deltatheroides; Gurbanodelta; Lotheridium; Nanocuris; Oklatheridium; Sulestes; Tsagandelta; ;

Deltatheroida is an extinct group of basal metatherians that were distantly related to modern marsupials.^[2] The majority of known members of the group lived in the Cretaceous; one species, Gurbanodelta kara, is known from the late Paleocene (Gashatan) of China.^[3] Their fossils are restricted to Central Asia and North America. This order can be defined as all metatherians closer to Deltatheridium than to Marsupialia.

When they were first identified in the 1920s, they were believed to be placentals and possible ancestors of the "creodonts" (a polyphyletic group of extinct carnivorous mammals from the Paleogene and Miocene), but this was later disproven. Nonetheless, deltatheroideans do converge on hyaenodontids, oxyaenids, carnivorans, dasyuromorphs, thylacoleonids and sparassodonts in many details of their dental anatomy, suggesting a carnivorous lifestyle.^[4]

^ Guillermo W. Rougier; Brian M. Davis; Michael J. Novacek (2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52, Part A: 167–177. doi:10.1016/j.cretres.2014.09.009.
^ Wilson, G.P.; Ekdale, E.G.; Hoganson, J.W.; Calede, J.J.; Linden, A.V. (2016). "A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials". Nature Communications. 7: 13734. Bibcode:2016NatCo...713734W. doi:10.1038/ncomms13734. PMC 5155139. PMID 27929063.
^ Xijun Ni; Qiang Li; Thomas A. Stidham; Lüzhou Li; Xiaoyu Lu; Jin Meng (2016). "A late Paleocene probable metatherian (?deltatheroidan) survivor of the Cretaceous mass extinction". Scientific Reports. 6: Article number 38547. Bibcode:2016NatSR...638547N. doi:10.1038/srep38547. PMC 5141426. PMID 27924847.
^ CHRISTIAN DE MUIZON and BRIGITTE LANGE-BADRÉ, Carnivorous dental adaptations in tribosphenic mammals and phylogenetic reconstruction, Article first published online: 29 MAR 2007 DOI: 10.1111/j.1502-3931.1997.tb00481