Boreoeutheria (sinonim Boreotheria) (dari Yunani Βορέας, Boreascode: grc is deprecated "tuhan Yunani, tuhan angin utara", εὐ-code: grc is deprecated , eu- "baik, benar" dan θηρίονcode: grc is deprecated , 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 65juta 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
↑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. PMID23393258.
↑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.
Waddell, PJ; Kishino, H; Ota, R (2001). "A phylogenetic foundation for comparative mammalian genomics". Genome Inform Ser Workshop Genome Inform. 12: 141–154.
Murphy, William J.; Eizirik, Eduardo; Springer, Mark S.; etal. (2001). "Resolution of the early placental mammal radiation using Bayesian phylogenetics". Science. 294 (5550): 2348–2351. doi:10.1126/science.1067179. PMID11743200.
