Atlantogenata

Alternative hypotheses are that Boreoeutheria and Afrotheria combine to form Epitheria (as generally supported by anatomical and other physiological evidence) or that Boreoeutheria and Xenarthra combine to form Exafroplacentalia or Notolegia.

According to some studies, updated analysis of transposable element insertions around the time of divergence strongly supports the fourth hypothesis of a near-concomitant origin (trifurcation) of the three superorders of placental mammals: Afrotheria, Boreoeutheria, and Xenarthra. However, a 2016 analysis concluded such conflicting phylogenies were a consequence of poorly fitting evolutionary models, and that the Atlantogenata hypothesis is the best supported. Based on a molecular clock analysis, crown-group Atlantogenata was estimated to have diverged 84–97 million years ago.

Below shows the phylogeny of the extant atlantogenate families.