Boreoeutheria
| Boreoeutheria Temporal range:
| |
|---|---|
| |
| From top to right: Artiodactyla and Perissodactyla, comprising Laurasiatheria .
| |
| |
| From top to left: Scandentia, comprising Euarchontoglires .
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | Eutheria |
| Infraclass: | Placentalia |
| Magnorder: | Boreoeutheria Springer & de Jong, 2001;[1] Murphy et al., 2001[2] |
| Superorders | |
| Synonyms | |
Boreoeutheria (/boʊˌriːoʊjuːˈθɛriə/, "northern true beasts") is a magnorder of placental mammals that groups together superorders Euarchontoglires and Laurasiatheria.[1][2][5] With a few exceptions,[a] male boreoeutherians have a scrotum, an ancestral feature of the clade.[6][7] The sub-clade Scrotifera was named after this feature.[8]
Etymology
The name of this magnorder comes from Ancient Greek words:
- Βορέας (Boreas) meaning 'north wind' or 'the North',
- εὐ- (eu-) meaning 'good', 'right', or 'true',
- and θηρίον (thēríon) meaning 'beast'.
Boreoeutherian ancestor
The majority of earliest known fossils belonging to this group date to about 66 million years ago, shortly after the
K-Pg extinction event, though molecular data suggest they may have originated earlier, during the Cretaceous period.[9][10] This is further supported with fossils of Altacreodus magnus and two species from genus Protungulatum
dated about 70.6 million years ago.
The
base pairs.[11]
Classification and phylogeny
Taxonomy
- Magnorder: Boreoeutheria (Springer & de Jong, 2001)
- Superorder: Euarchontoglires (Murphy, 2001)
- Superorder: Laurasiatheria (Waddell, 1999)
- Incertae sedis:
- Genus: †Veratalpa (Ameghino, 1905)[citation needed]
Phylogeny
The phylogenetic relationships of magnorder Boreoeutheria are shown in the following cladogram, reconstructed from mitochondrial and nuclear DNA and protein characters, as well as the fossil record.[4][9][10][13][14][15][16]
| Placentalia |
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See also
Notes
- ^ Exceptional clades whose males lack the usual boreoeutherian scrotum are moles, hedgehogs, pangolins, some pinnipeds, rhinoceroses, tapirs, hippopotamuses, and cetaceans.
References
- ^ S2CID 82844572.
- ^ S2CID 34367609.
- ^ Arnason U., Adegoke J. A., Gullberg A., Harley E. H., Janke A., Kullberg M. (2008.) "Mitogenomic relationships of placental mammals and molecular estimates of their divergences." Gene.; 421(1-2):37–51
- ^ PMID 11791233. Archived from the originalon 2019-07-10. Retrieved 2021-08-09.
- S2CID 24199924.
- ISBN 978-0-85199-724-7. Retrieved 20 June 2019.
- ^ Drew, Liam (8 July 2013). "Why are testicles kept in a vulnerable dangling sac?". slate.com.
Between these branches, however, is where it gets interesting, for there are numerous groups, our descended but a-scrotal cousins, whose testes drop down away from the kidneys but don't exit the abdomen. Almost certainly, these animals evolved from ancestors whose testes were external, which means at some point they backtracked ... , evolving anew gonads inside the abdomen. They are a ragtag bunch including hedgehogs, moles, rhinos and tapirs, hippopotamuses, dolphins and whales, some seals and walruses, and scaly anteaters.
- PMID 12078643..
The name comes from the word scrotum a pouch in which the testes permanently reside in the adult male. All members of the group have a postpenile scrotum, often prominently displayed, except for some aquatic forms and pangolins (which have the testes just below the skin). It appears to be an ancestral character for this group, yet other orders generally lack this as an ancestral feature, with the probable exception of Primates
- ^ PMID 21900649.
- ^ S2CID 206544776.
- ^ a b John Roach (25 Jan 2005). "Scientists recreate genome of ancient human ancestor". National Geographic. Archived from the original on March 21, 2006. Retrieved 14 Feb 2015.
- PMID 15574820.
- PMID 27325836.
- PMID 28934378.
- ^ Frank Zachos (2020.) "Mammalian Phylogenetics: A Short Overview of Recent Advances", In book: "Mammals of Europe - Past, Present, and Future" (pp.31-48)
- ^ Xue Lv, Jingyang Hu, Yiwen Hu, Yitian Li, Dongming Xu, Oliver A. Ryder, David M. Irwin, Li Yu (2021.) "Diverse phylogenomic datasets uncover a concordant scenario of laurasiatherian interordinal relationships", Molecular Phylogenetics and Evolution, Volume 157
Additional references
- Waddell, P. J.; Kishino, H.; Ota, R. (2001). "A phylogenetic foundation for comparative mammalian genomics". Genome Inform Ser Workshop Genome Inform. 12: 141–154. PMID 11791233.
- Murphy, William J.; Eizirik, Eduardo; Springer, Mark S.; et al. (2001). "Resolution of the early placental mammal radiation using Bayesian phylogenetics". Science. 294 (5550): 2348–2351. S2CID 34367609.
- Blanchette, M.; Green, E. D.; Miller, W.; Haussler, D (Dec 2004). "Reconstructing large regions of an ancestral mammalian genome in silico". Genome Research. 14 (12): 2412–2423. PMID 15574820.
- Kriegs; Ole, Jan; Churakov, Gennady; Kiefmann, Martin; Jordan, Ursula; Brosius, Juergen; Schmitz, Juergen (2006). "Retroposed elements as archives for the evolutionary history of placental mammals". PLOS Biology. 4 (4): e91. PMID 16515367.
- Ma, J.; Zhang, L.; Suh, B. B.; Raney, B. J.; Burhans, R. C.; Kent, W. J.; Blanchette, M.; Haussler, D.; Miller, W. (Dec 2006). "Reconstructing contiguous regions of an ancestral genome". Genome Research. 16 (12): 1557–1565. PMID 16983148.
External links
- Gross, Liza (14 March 2006). "Resolving the family tree of placental mammals". PLOS Biology. 4 (4): e111. PMID 20076552.
- Olson, Steve (April 2006). "Bringing back the brontosaurus". Wired.
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