Which Is Older Marsupials or Placentals?

Genetic analysis suggests a divergence date between the marsupials and the placentals at 160 million years ago.

Did marsupials or placentals come first?

Mammals continued to evolve. Monotreme mammals probably split off from other mammals first. They were followed by marsupials. Placental mammals probably evolved last.

Are marsupials older than placentals?

Recent DNA studies suggest placental mammals began to diverge from marsupials as early as 175 million years ago. Thus far, the fossil record has not shown this, perhaps because paleontologists trying to date the split have only little teeth and jawbones to work with.