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Temporal range: Late JurassicHolocene, 161–0 Ma
Fossil of Leptictis, a non-placental eutherian from the Paleogene of North America
Grévy's zebra, a placental eutherian from modern Africa
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass: Theria
Clade: Eutheria
Gill, 1872

see text.

Eutheria (from Greek εὐ-, eú- 'good, right' and θηρίον, thēríon 'beast'; lit.'true beasts'), also called Placentalia sensu lato or Pan-Placentalia, is the clade consisting of placental mammals and all therian mammals that are more closely related to placentals than to marsupials.

Eutherians are distinguished from noneutherians by various phenotypic traits of the feet, ankles, jaws and teeth. All extant eutherians lack epipubic bones, which are present in all other living mammals (marsupials and monotremes). This allows for expansion of the abdomen during pregnancy.[1]

The oldest-known eutherian species is Juramaia sinensis, dated at 161 million years ago from the early Late Jurassic (Oxfordian) of China.[2]

Eutheria was named in 1872 by Theodore Gill; in 1880 Thomas Henry Huxley defined it to encompass a more broadly defined group than Placentalia.[3]


The entocuneiform bone

Distinguishing features are:

  • an enlarged malleolus ("little hammer") at the bottom of the tibia, the larger of the two shin bones[4]
  • the joint between the first metatarsal bone and the entocuneiform bone (the innermost of the three cuneiform bones) in the foot is offset farther back than the joint between the second metatarsal and middle cuneiform bones—in metatherians these joints are level with each other[4]
  • various features of jaws and teeth[4]


Eutheria [=Placentalia sensu lato, Pan-Placentalia]:[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]


-The above three genera Purgatorius, Protungulatum and Oxyprimus are often placed within Placentalia sensu stricto.
-Older systems often contained an order called Cimolesta (sensu lato), which contains the above taxa Cimolestidae, Taeniodonta and Didymoconidae, but also (all or some of) the taxa †Ptolemaiidae, †Palaeoryctidae, †Wyolestidae, †Pantolesta (probably inclusive of the family †Horolodectidae), †Tillodontia, †Apatotheria, †Pantodonta, Pholidota and †Palaeanodonta. Those additional taxa (all of which are usually considered members of Placentalia sensu stricto today) were thus also placed among basal Eutheria in such older systems and were placed next to Cimolestidae.
-Some older systems also included the †Creodonta and/or †Dinocerata as basal Eutherians.
-Some authors classify the taxa, which are at the end of the above system of basal Eutheria, as part of Placentalia sensu stricto. More specifically, depending on the author, this applies to the taxa of the above system that are placed from (and inclusive of) Leptictida or from Asioryctitheria or from Adapisoriculidae down to (and inclusive of) Oxyprimus.

Evolutionary history[edit]

Eutheria contains several extinct genera as well as larger groups, many with complicated taxonomic histories still not fully understood. Members of the Adapisoriculidae, Cimolesta and Leptictida have been previously placed within the outdated placental group Insectivora, while Zhelestids have been considered primitive ungulates.[27] However, more recent studies have suggested these enigmatic taxa represent stem group eutherians, more basal to Placentalia.[28][29]

The weakly favoured cladogram favours Boreoeutheria as a basal eutherian clade as sister to the Atlantogenata.[30][31][32]







The fossil eutherian species believed to be the oldest known is Juramaia sinensis, which lived about 160 million years ago.[2] Montanalestes was found in North America, while all other nonplacental eutherian fossils have been found in Asia. The earliest-known placental fossils have also been found in Asia.[4]



Other mammaliaformes








Simplified, non-systematic, outline of evolution of eutheria from cynodont therapsids.[4]
† = extinct


  1. ^ Reilly, Stephen M.; White, Thomas D. (2003-01-17). "Hypaxial Motor Patterns and the Function of Epipubic Bones in Primitive Mammals". Science. 299 (5605): 400–402. Bibcode:2003Sci...299..400R. doi:10.1126/science.1074905. ISSN 0036-8075. PMID 12532019.
  2. ^ a b Luo, Z.; C. Yuan; Q. Meng; Q. Ji (2011). "A Jurassic eutherian mammal and divergence of marsupials and placentals". Nature. 476 (7361): 42–45. Bibcode:2011Natur.476..442L. doi:10.1038/nature10291. PMID 21866158.
  3. ^ Eutheria (Placental Mammals) by J David Archibald, San Diego State University, San Diego, California, USA. PDF file from
  4. ^ a b c d e Ji, Q.; Luo, Z-X.; Yuan, C-X.; Wible, J.R.; Zhang, J-P. & Georgi, J.A. (April 2002). "The earliest known eutherian mammal". Nature. 416 (6883): 816–822. Bibcode:2002Natur.416..816J. doi:10.1038/416816a. PMID 11976675.
  5. ^ Zachos, F.; Asher, R. (2018). Mammalian Evolution, Diversity and Systematics. De Gruyter. pp. 271–339, mainly p. 277. ISBN 978-3-11-034155-3.
  6. ^ Benton, Michael J. (2014-10-20). Vertebrate Palaeontology. Chichester: John Wiley & Sons. pp. 443–444. ISBN 978-1-118-40755-4.
  7. ^ Zima, Jan; Macholán, Miloš (2021). Systém a fylogeneze savců (in Czech). pp. 130–149. ISBN 978-80-200-3215-7.
  8. ^ Lopatin, Alexey & Averianov, Alexander. (2018). Earliest Placentals: at the Dawn of Big Time / Древнейшие плацентарные: начало истории успеха. Priroda. 34-40. [1]
  9. ^ Velazco, P.M., Buczek, A.J., Hoffman, E., Hoffman, D.K., O’Leary, M.A. and Novacek, M.J. (2022), Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia. Cladistics, 38: 359-373.
  10. ^ Bi, Shundong; Zheng, Xiaoting; Wang, Xiaoli; Cignetti, Natalie E.; Yang, Shiling; Wible, John R. (2018). "An Early Cretaceous eutherian and the placental–marsupial dichotomy". Nature. 558 (7710): 390–395. Bibcode:2018Natur.558..390B. doi:10.1038/s41586-018-0210-3. ISSN 1476-4687. PMID 29899454. S2CID 91737831
  11. ^ Wang, Hai-Bing; Hoffmann, Simone; Wang, Dian-Can; Wang, Yuan-Qing (7 February 2022). "A new mammal from the Lower Cretaceous Jehol Biota and implications for eutherian evolution". Philosophical Transactions of the Royal Society B. 377 (1847). doi:10.1098/rstb.2021.0042. PMC 8819371. PMID 35125007.
  12. ^ Rook, Deborah L.; Hunter, John P. (2013). "Rooting Around the Eutherian Family Tree: the Origin and Relations of the Taeniodonta". Journal of Mammalian Evolution: 1–17. doi:10.1007/s10914-013-9230-9.
  13. ^ Maureen A. O'Leary et al. Placentals K-Pg Radiation of−The Placental Mammal Ancestor and the Post-K-Pg Radiation of−Placentals. Science 339, 662 (2013)
  14. ^ Rose, Kenneth D. (2006-09-26). The Beginning of the Age of Mammals. Baltimore (Md.): JHU Press. ISBN 0-8018-8472-1. ch. 6 and ch. 7
  15. ^ Halliday, T.J.D., Upchurch, P. and Goswami, A. (2017), Resolving the relationships of Paleocene placental mammals. Biol Rev, 92: 521-550.
  16. ^ Manz, Carly L.; Chester, Stephen G. B.; Bloch, Jonathan I.; Silcox, Mary T.; Sargis, Eric J. (2015). "New partial skeletons of Palaeocene Nyctitheriidae and evaluation of proposed euarchontan affinities". Biology Letters. The Royal Society. 11 (1): 20140911. doi:10.1098/rsbl.2014.0911. ISSN 1744-9561.
  17. ^ Averianov, Alexander. (2012). A new eutherian mammal from the Late Cretaceous of Kazakhstan. Acta Palaeontologica Polonica. 59. 10.4202/app.2011.0143.
  18. ^ "Eutheria". 2018-02-27. Retrieved 2023-11-13.
  19. ^ "Palaeos Vertebrates: Archaic Mammals: Creodonts". Palaeos. Retrieved 2023-11-14.
  20. ^ Cifelli, Richard & Davis, Brian. (2015). Tribosphenic Mammals from the Lower Cretaceous Cloverly Formation of Montana and Wyoming. Journal of Vertebrate Paleontology. 35. e920848. 10.1080/02724634.2014.920848.
  21. ^ Sargis, E.J.; Dagosto, M. (2008). Mammalian Evolutionary Morphology: A Tribute to Frederick S. Szalay. Vertebrate Paleobiology and Paleoanthropology. Springer Netherlands. p. 5. ISBN 978-1-4020-6997-0. Retrieved 2023-11-13.
  22. ^ KIELAN-JAWOROWSKA, Z. : Evolution of the therian mammals in the Late Cretaceous of Asia. PART I. DELTATHERIDIIDAE (plates XXVIII-XXXV). 1984. p. 123, 124 [2]
  23. ^ Wang, Y-Q & Kusuhashi, Nao & Jin, Xun & Chuan-kui, LI & Takeshi, SETOGUCHI & Chun-Ling, GAO & Jin-Yuan, LIU & Palasiatica, Vertebrata. (2018). Reappraisal of Endotherium niinomii Shikama, 1947, a eutherian mammal from the Lower Cretaceous Fuxin Formation, Fuxin-Jinzhou Basin, Liaoning, China.
  24. ^ Wilson Mantilla, Gregory P.; Renne, Paul R.; Samant, Bandana; Mohabey, Dhananjay M.; Dhobale, Anup; Tholt, Andrew J.; Tobin, Thomas S.; Widdowson, Mike; Anantharaman, S.; Dassarma, Dilip Chandra; Wilson Mantilla, Jeffrey A. (2022). "New mammals from the Naskal intertrappean site and the age of India's earliest eutherians". Palaeogeography, Palaeoclimatology, Palaeoecology. Elsevier BV. 591. doi:10.1016/j.palaeo.2022.110857. ISSN 0031-0182.
  25. ^ Craig S Scott, Horolodectidae: a new family of unusual eutherians (Mammalia: Theria) from the Palaeocene of Alberta, Canada, Zoological Journal of the Linnean Society, Volume 185, Issue 2, February 2019, Pages 431–458,
  26. ^ Kynigopoulou, Zoi. Phylogeny, evolution, and anatomy of Taeniodonta (Mammalia: Eutheria) and implications for the mammalian evolution after the Cretaceous-Palaeogene mass extinction. 2023 [3]
  27. ^ Rose, Kenneth D. (2006). The beginning of the age of mammals. Baltimore: Johns Hopkins University Press. ISBN 9780801892219.
  28. ^ Wible, J. R.; Rougier, G. W.; Novacek, M. J.; Asher, R. J. (2007). "Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary". Nature. 447 (7147): 1003–1006. Bibcode:2007Natur.447.1003W. doi:10.1038/nature05854. PMID 17581585.
  29. ^ Wible, John R.; Rougier, Guillermo W.; Novacek, Michael J.; Asher, Robert J. (2009). "The Eutherian Mammal Maelestes gobiensis from the Late Cretaceous of Mongolia and the phylogeny of cretaceous eutheria" (PDF). Bulletin of the American Museum of Natural History. 327: 1–123. doi:10.1206/623.1. hdl:2246/6001.
  30. ^ Foley, Nicole M.; Springer, Mark S.; Teeling, Emma C. (2016-07-19). "Mammal madness: is the mammal tree of life not yet resolved?". Phil. Trans. R. Soc. B. 371 (1699): 20150140. doi:10.1098/rstb.2015.0140. PMC 4920340. PMID 27325836.
  31. ^ Tarver, James E.; Reis, Mario dos; Mirarab, Siavash; Moran, Raymond J.; Parker, Sean; O'Reilly, Joseph E.; King, Benjamin L.; O'Connell, Mary J.; Asher, Robert J. (2016-02-01). "The Interrelationships of Placental Mammals and the Limits of Phylogenetic Inference". Genome Biology and Evolution. 8 (2): 330–344. doi:10.1093/gbe/evv261. PMC 4779606. PMID 26733575.
  32. ^ Esselstyn, Jacob A.; Oliveros, Carl H.; Swanson, Mark T.; Faircloth, Brant C. (2017-08-26). "Investigating Difficult Nodes in the Placental Mammal Tree with Expanded Taxon Sampling and Thousands of Ultraconserved Elements". Genome Biology and Evolution. 9 (9): 2308–2321. doi:10.1093/gbe/evx168. PMC 5604124. PMID 28934378.