👉 Perognathinae is a group of extinct reptiles that lived during the Cretaceous period, approximately 68 million years ago. These creatures were characterized by their long necks and large jaws, which allowed them to swim efficiently in freshwater environments. They are known for their unique adaptations, such as having thick layers of feathers on their upper body and a specialized respiratory system with air sacs for gas exchange. The genus Perognathus is particularly notable due to its distinctive skull structure