aug 15, 180000000 BC - Monotremes split from other mammals
Description:
Monotremes give birth externally, laying eggs instead of carrying a child inside a mother's body. They also differ structurally in several regards from other mammals, such as in the digestive and reprotductive systems. With some exceptions, most of these are extinct today.
Added to timeline:
Chordate Evolution over Geologic Time
Phanerozoic geologic time scale showcasing evolutionary deve...
Date:
