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Boreoeutheria

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Boreoeutheria
Klasifikasi ilmiah Sunting klasifikasi ini
Domain: Eukaryota
Kerajaan: Animalia
Filum: Chordata
Kelas: Mammalia
Infrakelas: Placentalia
Magnordo: Boreoeutheria
Subgrup

Boreoeutheria (sinonim Boreotheria) (dari Yunani Βορέας, Boreas "tuhan Yunani, tuhan angin utara", εὐ-, eu- "baik, benar" dan θηρίον, thēríon "buas" (apabila digabungkan menjadi "Binatang buas utara yang nyata") adalah klad (magnorder) mamalia berplasenta yang terdiri dari Laurasiatheria dan Euarchontoglires (Supraprimata). Pengelompokan ini didukung dengan analisis pengurutan DNA.[butuh rujukan] Mamalia berplasenta diluar klad ini ialah Xenarthra dan Afrotheria.

Fosil yang paling awal diketahui sekitar 65 juta tahun lalu, segera setelah Peristiwa kepunahan Kapur–Paleogen, meskipun data molekul memperkirakan kelompok hewan ini mungkin lebih awal dari itu, yaitu saat zaman Cretaceous.[1] Dengan beberapa pengecualian [2] Hewan jantan memiliki skrotum.[3][4] Sub-klad Scrotifera dinamai karena hal ini.[5]

Referensi

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  1. ^ O'Leary, M. A.; Bloch, J. I.; Flynn, J. J.; Gaudin, T. J.; Giallombardo, A.; Giannini, N. P.; Cirranello, A. L. (2013). "The placental mammal ancestor and the post–K-Pg radiation of placentals". Science. 339 (6120): 662–667. doi:10.1126/science.1229237. PMID 23393258. 
  2. ^ Klad boreoeutherian yang tidak memiliki skrotum adalah tikus tanah, landak, anteater, beberapa anjing laut dan badak, tapir, kuda nil, dan ikan paus.
  3. ^ Mills, D. S.; Marchant-Forde, Jeremy N. (2010). The Encyclopedia of Applied Animal Behaviour and Welfare. CABI. hlm. 293–. ISBN 978-0-85199-724-7. Diakses tanggal 20 June 2019. 
  4. ^ 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. 
  5. ^ Waddell; et al. (1999). "Using novel phylogenetic methods to evaluate mammalian mtDNA, including amino acid-invariant sites-LogDet plus site stripping, to detect internal conflicts in the data, with special reference to the positions of hedgehog, armadillo, and elephant". Systematic Biology. 48 (1): 31–53. doi:10.1080/106351599260427. Diakses tanggal 4 October 2011. 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. 

Referensi tambahan

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