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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  

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:

Another alternative hypothesis is the Atlantogenata hypothesis:

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]

See also

References

  1. ^ a b 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. ^ a b 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

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