👉 Thyatirinae is a group of ancient, highly differentiated, aquatic creatures that lived in the ocean and were the first living organisms on Earth, dating back over 500 million years ago. These creatures had a unique adaptation known as the "thyat," which allowed them to breathe underwater through gills. They were characterized by their elongated bodies, large eyes, and a long snout that could extend up to 2 meters (6 feet) in length.