Final answer:
The Cynognathus, a Carnosaur, is recently thought to have spent much of its life in the water due to fossil evidence that indicates it was a weak swimmer and had features suggesting it lived in water bodies. It lived during the Early Mesozoic Era about 230 million years ago.
Step-by-step explanation:
The Cynognathus, which is a Carnosaur, is recently thought to have spent much of its life in the water. Fossil evidence indicates that the Cynognathus was a weak swimmer and had features that suggest it lived in lakes and coastal bays or estuaries. It is believed to have lived during the Early Mesozoic Era about 230 million years ago.