Laurasiatheria

Laurasiatheria Fossil range: Late Cretaceous - Recent PreЄ Є O S D C P T J K Pg N
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
Erinaceomorpha Soricomorpha Chiroptera Cetartiodactyla Cetacea Artiodactyla Perissodactyla Ferae: Pholidota Carnivora Insectivora

Laurasiatheria is a large group of placental mammals. It includes bats, whales, most hoofed mammals, and carnivorans, among other mammals.

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 the Laurasiatheria, the Erinaceomorpha appears (surprisingly) to be the most divergent branch. Some studies link the Perissodactyla and Ferae in a clade Zooamata; others link Perissodactyla and Cetartiodactyla in a clade of true ungulates. Neither clade is well supported.

Laurasiatheria is also posited to include several extinct orders and superorders:

• Meridiungulata
• Condylarthra
• Dinocerata
• Mesonychia
• Cimolesta
• Creodonta

Cladogram

References

1. ↑ 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. http://www.deer.rr.ualberta.ca/library/taxonomy/reading.pdf. Retrieved 2009-10-26. 

• 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, Juergen Brosius, Juergen 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

See also

• Boreoeutheria

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