Exafroplacentalia

Exafroplacentalia Temporal range: Paleocene - Holocene, 65–0  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Placentalia
Clade:	Exafroplacentalia Waddell et al, 2001 [1]
Subgroups
Superorder Xenarthra: Order Cingulata (Armadillos) Order Pilosa (Anteaters, sloths) Magnorder Boreoeutheria: Superorder Laurasiatheria Superorder Euarchontoglires Afrotheria?

Exafroplacentalia or Notolegia is a clade of placental mammals proposed in 2001 on the basis of molecular research. ^{[1] [2] [3]}

Exafroplacentalia places Xenarthra as a sister group to the Boreoeutheria (comprising Laurasiatheria and Euarchontoglires), ^[4] thus making Afrotheria a primitive group of placental mammals (the group name roughly means "those which are not African placentals").

Classification

Eutheria	Afrotheria Exafroplacentalia Xenarthra Boreoeutheria Laurasiatheria Euarchontoglires

However, this classification makes the autapomorphy (character shared only among Exafroplacentalia) dubious: it is hard to classify a group by the absence of a feature (in this case "not coming from Africa"). ^[5] Hence, several alternative hypotheses can be considered.

Alternative hypotheses

One alternative hypothesis is the Epitheria hypothesis:

Placentalia	Xenarthra Epitheria Afrotheria Boreoeutheria Euarchontoglires Laurasiatheria

Another alternative hypothesis is the Atlantogenata hypothesis:

Eutheria	Atlantogenata Xenarthra Afrotheria Boreoeutheria Euarchontoglires Laurasiatheria

Updated analysis of transposable element insertions around the time of divergence strongly supports the fourth hypothesis of a near-concomitant origin of the three superorders of mammals: ^[5]

Eutheria	Xenarthra Afrotheria Boreoeutheria Euarchontoglires Laurasiatheria

See also

• Epitheria
• Atlantogenata

References

1. Waddell, Peter J.; Kishino, Hirohisa; Ota, Rissa (2001). "A phylogenetic foundation for comparative mammalian genomics". Genome Informatics . 12: 141–154. doi:10.11234/gi1990.12.141. PMID   11791233. Archived from the original on 2019-07-10. Retrieved 2015-08-28.
2. Murphy, W.J., Pringle, T.H., Crider, T.A., Springer, M.S. & Miller, W. 2007. Using genomic data to unravel the root of the placental mammal phylogeny. Genome Research 17, pp.413-421.
3. Kriegs, J.O., Churakov, G., Kiefmann, M., Jordan, U., Brosius, J. & Schmitz, J. 2006. Retroposed elements as archives for the evolutionary history of placental mammals. Plos Biol 4, pp.e91.
4. Goloboff, Pablo A.; Catalano, Santiago A.; Mirande, J. Marcos; Szumik, Claudia A.; Arias, J. Salvador; Källersjö, Mari; Farris, James S. (2009). "Phylogenetic analysis of 73 060 taxa corroborates major eukaryotic groups". Cladistics . 25 (3): 211–230. doi: 10.1111/j.1096-0031.2009.00255.x . hdl: 11336/78055 . PMID   34879616.
5. Nishihara, H., Maruyama, S. & Okada, N. 2009. Retroposon analysis and recent geological data suggest near-simultaneous divergence of the three superorders of placental mammals. PNAS 106: 5235-40.

Further reading

• Churakov, G.; Kriegs, J. O.; Baertsch, R.; Zemann, A.; Brosius, J. R.; Schmitz, J. R. (2009). "Mosaic retroposon insertion patterns in placental mammals". Genome Research . 19 (5): 868–875. doi:10.1101/gr.090647.108. PMC   2675975 . PMID   19261842.
• Nikolaev, Sergey; Montoya-Burgos, Juan I.; Margulies, Elliott H.; NISC Comparative Sequencing Program; Rougemont, Jacques; Nyffeler, Bruno; Antonarakis, Stylianos E. (2007). "Early History of Mammals is Elucidated with the ENCODE Multiple Species Sequencing Data". PLoS Genetics . 3 (1): e2. doi: 10.1371/journal.pgen.0030002 . PMC   1761045 . PMID   17206863.
• Springer, Mark S.; Murphy, William J.; Eizirik, Eduardo; O'Brien, Stephen J. (2003). "Placental mammal diversification and the Cretaceous–Tertiary boundary". Proceedings of the National Academy of Sciences . 100 (3): 1056–1061. doi: 10.1073/pnas.0334222100 . PMC   298725 . PMID   12552136.
• Wildman, Derek E.; Chen, Caoyi; Erez, Offer; Grossman, Lawrence I.; Goodman, Morris; Romero, Roberto (2006). "Evolution of the mammalian placenta revealed by phylogenetic analysis". Proceedings of the National Academy of Sciences . 103 (9): 3203–3208. doi: 10.1073/pnas.0511344103 . PMC   1413940 . PMID   16492730.