4 ms·

What common ancestor? You risk going so far back your suggestion is meaningless

• dredmorbius 12y ago
  ~ 320 - 315 mya, amniotes. https://en.wikipedia.org/wiki/Evolution_of_mammals#The_ancestry_of_mammals https://en.wikipedia.org/wiki/Evolution_of_mammals#The_ances... https://en.wikipedia.org/wiki/Amniote https://en.wikipedia.org/wiki/Amniote