👉 Placodontia is a group of extinct mammals that lived during the Late Cretaceous period, around 65 to 62 million years ago. These animals were known for their long necks and large teeth, which allowed them to reach high places like trees and rocks. Some examples of placodontia include: 1. Bactrodeus: a large carnivorous mammal that lived in the Late Cretaceous period. 2. Placentalia: a group of