Placentalia

From Palaeos.org

The below tree is based primarily on the morphological analysis of Wible et al. 2007:

<==Placentalia (see below for synonymy)
   |--+--Chiroptera
   |  `--Cetferungulata
   `--+--Euarchontaglires
      |    |--Euarchonta
      |    `--Glires
      `--+--Lipotyphla
         `--+--Afrotheria
            `--Xenarthra

An Alternative Hypothesis

Molecular studies tend to find a rather different pattern; the below tree is based primarily on Nishihara et al. 2007. It excludes extinct taxa as, for obvious reasons, they are not available for genetic analysis.

<==Placentalia
   |--Atlantogenata
   |    |--Afrotheria
   |    `--Xenarthra
   `--Boreoeutheria
        |--Euarchontoglires
        |    |--Euarchonta
        |    `--Glires
        `--Laurasiatheria
             |--Lipotyphla
             `--+--Cetartiodactyla
                `--Pegasoferae
                     |--Chiroptera
                     `--+--Carnivora
                        `--Perissodactyla

References

Murphy WJ, Pringle TH, Crider TA, Springer MS, Miller W (2007). "Using genomic data to unravel the root of the placental mammal phylogeny". Genome Res. 17 (4): 413–21. doi:10.1101/gr.5918807. PMID 17322288. http://genome.cshlp.org/content/17/4/413.long.

Nishihara, H., Hasegawa, M., & Okada, N. (2006). Pegasoferae, an unexpected mammalian clade revealed by tracking ancient retroposon insertions. Proceedings of the National Academy of Sciences of the United States of America, 103, 9929-9934.

Wible, J. R., G. W. Rougier, M. J. Novacek & R. J. Asher. 2007. Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary. Nature 447: 1003-1006.

Credits

Christopher 00:36, 6 August 2009 (UTC), HAJ100101