Atlantogenata ("born around the Atlantic Ocean") is a magnorder of placental mammals containing the cohorts or superorders Xenarthra and Afrotheria. These groups originated and radiated in the South American and African continents, respectively, presumably in the Cretaceous. Together with Boreoeutheria, they make up Placentalia. The monophyly of this grouping is supported by some genetic evidence.

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.

PlacentaliaAtlantogenata Xenarthra Afrotheria Boreoeutheria Laurasiatheria Euarchontoglires
AtlantogenataXenarthra Afrotheria
Xenarthra
Afrotheria
BoreoeutheriaLaurasiatheria Euarchontoglires
Laurasiatheria
Euarchontoglires

Below shows the phylogeny of the extant atlantogenate families.

AtlantogenataXenarthra Cingulata Dasypodidae Chlamyphoridae Pilosa Vermilingua Cyclopedidae Myrmecophagidae Folivora Bradypodidae Choloepodidae Afrotheria Paenungulata Hyracoidea Procaviidae Tethytheria Sirenia Trichechidae Dugongidae Proboscidea Elephantidae Afroinsectiphilia Tubulidentata Orycteropodidae Afroinsectivora Macroscelidea Macroscelididae Afrosoricida Chrysochloridae Tenrecomorpha Potamogalidae Tenrecidae
XenarthraCingulata Dasypodidae Chlamyphoridae Pilosa Vermilingua Cyclopedidae Myrmecophagidae Folivora Bradypodidae Choloepodidae
CingulataDasypodidae Chlamyphoridae
Dasypodidae
Chlamyphoridae
PilosaVermilingua Cyclopedidae Myrmecophagidae Folivora Bradypodidae Choloepodidae
VermilinguaCyclopedidae Myrmecophagidae
Cyclopedidae
Myrmecophagidae
FolivoraBradypodidae Choloepodidae
Bradypodidae
Choloepodidae
AfrotheriaPaenungulata Hyracoidea Procaviidae Tethytheria Sirenia Trichechidae Dugongidae Proboscidea Elephantidae Afroinsectiphilia Tubulidentata Orycteropodidae Afroinsectivora Macroscelidea Macroscelididae Afrosoricida Chrysochloridae Tenrecomorpha Potamogalidae Tenrecidae
PaenungulataHyracoidea Procaviidae Tethytheria Sirenia Trichechidae Dugongidae Proboscidea Elephantidae
HyracoideaProcaviidae
TethytheriaSirenia Trichechidae Dugongidae Proboscidea Elephantidae
SireniaTrichechidae Dugongidae
Trichechidae
Dugongidae
ProboscideaElephantidae
AfroinsectiphiliaTubulidentata Orycteropodidae Afroinsectivora Macroscelidea Macroscelididae Afrosoricida Chrysochloridae Tenrecomorpha Potamogalidae Tenrecidae
TubulidentataOrycteropodidae
AfroinsectivoraMacroscelidea Macroscelididae Afrosoricida Chrysochloridae Tenrecomorpha Potamogalidae Tenrecidae
MacroscelideaMacroscelididae
AfrosoricidaChrysochloridae Tenrecomorpha Potamogalidae Tenrecidae
Chrysochloridae
TenrecomorphaPotamogalidae Tenrecidae
Potamogalidae
Tenrecidae

Further reading