| Laurasiatheria Temporal range: Late Cretaceous - Recent |
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| Clockwise from the upper left: giraffe, golden crown fruit bat, lion, hedgehog | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Subclass: | Theria |
| Infraclass: | Eutheria |
| Magnorder: | Boreoeutheria |
| Superorder: | Laurasiatheria Waddell et al. 1999 [1] |
| Orders | |
Laurasiatheria is a large group of placental mammals believed to have originated on the northern supercontinent of Laurasia. It includes shrews, hedgehogs, pangolins, bats, whales, most hoofed mammals, and carnivorans, among others.
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Classification and phylogeny
Laurasiatheria was discovered on the basis of the similar gene sequences shared by the mammals belonging to it. No anatomical features have yet been found that unite the group. Laurasiatheria is a clade usually discussed without a Linnaean rank, but has been assigned the rank of cohort or magnorder, and superorder. The Laurasiatheria clade is based on DNA sequence analyses and retrotransposon presence/absence data. The name comes from the theory that these mammals evolved on the supercontinent of Laurasia, after it split from Gondwana when Pangaea broke up. It is a sister group to Euarchontoglires (Supraprimates) and Afrotheria. It includes the following extant orders:
- Erinaceomorpha: hedgehogs and gymnures
- Soricomorpha: moles, shrews, solenodons (cosmopolitan)
- Cetacea: whales, dolphins and porpoises (cosmopolitan)
- Artiodactyla: even-toed ungulates, including pigs, hippopotamuses, camels, giraffes, deer, antelopes, cattle, sheep, goats (cosmopolitan)
- Pegasoferae:
- Pholidota: pangolins or scaly anteaters (Africa, South Asia)
- Chiroptera: bats (cosmopolitan)
- Carnivora: cats, dogs, bears, seals, and others (cosmopolitan)
- Perissodactyla: odd-toed ungulates
Within Laurasiatheria, Erinaceomorpha appears (surprisingly[clarification needed]) to be the most divergent branch. Some studies link Perissodactyla and Ferae in the clade Zooamata; others link Perissodactyla and Cetartiodactyla in a clade of true ungulates[citation needed]. Neither clade is well supported[citation needed].
Laurasiatheria is also posited to include several extinct orders and superorders:
Cladogram
| Laurasiatheria |
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See also
References
- ^ Waddell, Peter J., Okada, Norihiro, & Hasegawa, Masami (1999). "Towards resolving the interordinal relationships of placental mammals". Systematic Biology 48 (1): 1–5. doi:10.1093/sysbio/48.1.1. PMID 12078634. http://www.deer.rr.ualberta.ca/library/taxonomy/reading.pdf. Retrieved 2009-10-26.
Further reading
- William J. Murphy, Eduardo Eizirik, Mark S. Springer et al., Resolution of the Early Placental Mammal Radiation Using Bayesian Phylogenetics,Science, Vol 294, Issue 5550, 2348–2351, 14 December 2001.
- Jan Ole Kriegs, Gennady Churakov, Martin Kiefmann, Ursula Jordan, Jürgen Brosius, Jürgen Schmitz. (2006) Retroposed Elements as Archives for the Evolutionary History of Placental Mammals. PLoS Biol 4(4): e91.[1] (pdf version)
- Kitazoe Y, Kishino H, Waddell PJ, Nakajima N, Okabayashi T, et al. (2007) "Robust Time Estimation Reconciles Views of the Antiquity of Placental Mammals." PLoS ONE 2(4): e384. doi:10.1371/journal.pone.0000384
External links
- Waddell PJ, Kishino H, Ota R. 2001. A phylogenetic foundation for comparative mammalian genomics. Genome Inform Ser Workshop Genome Inform 12: 141–154
- Placental mammal diversification and the Cretaceous-Tertiary boundary
- Wildman D.E.; Chen C.; Erez O.; Grossman L.I.; Goodman M.; Romero R. 2006. Evolution of the mammalian placenta revealed by phylogenetic analysis. PNAS 103 (9): 3203–3208
- Nikolaev, S., Montoya-Burgos, J.I., Margulies, E.H., Rougemont, J., Nyffeler, B., Antonarakis, S.E. 2007. Early history of mammals is elucidated with the ENCODE multiple species sequencing data. PLoS Genet. 3:e2, doi:10.1371/journal.pgen.0030002.
- Gennady Churakov, Jan Ole Kriegs, Robert Baertsch, Anja Zemann, Jürgen Brosius, Jürgen Schmitz. 2008. Mosaic retroposon insertion patterns in placental mammals
- Goloboff, P.A.; Catalano, S.A.; Mirande, J.M.; Szumik, C.A.; Arias, J.S.; Källersjö, M & Farris, J.S. 2009. Phylogenetic analysis of 73 060 taxa corroborates major eukaryotic groups. Cladistics 25 (3): 211–230
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