What dinosaur was considered a direct ancestor to placenta mammals, and marsupials?

Question

What dinosaur was considered a direct ancestor to placenta mammals, and marsupials?

Answer 1

None. Dinosaurs evolved from diapsid reptiles - those with two pairs of holes in the skull behind the eyes. Mammals evolved from a group of synapsid reptiles, in which the two pairs of holes behind the eyes are fused into one, called therapsids or 'mammal-like reptiles'. The most famous synapsid is probably the sail-backed Dimetrodon - it's often mistaken for a dinosaur, but lived around 50 million years before dinosaurs evolved. Here's an image:

http://upload.wikimedia.org/wikipedia/co...

Answer 2

None. We did not evolve from dinosaurs but a completely different line of animals.

Answer 3

I know dimetrodon was mammal like lizard.