Alex McCurthy
Before the dinosaurs roamed the Earth, a variety of other creatures were alive. For approximately 120 million years, from the Carboniferous to the middle Triassic periods, terrestrial life was dominated by the pelycosaurs, archosaurs, and therapsids. These are collectively known as the “mammal-like reptiles” and were the predecessors of the dinosaurs.
The pelycosaurs were the first of the “mammal-like reptiles” to appear on Earth. They were large, four-legged animals with long, pointed heads and long, slender tails. They were the first animals to develop the ability to regulate their body temperature, and they were the first to have a bony skeleton. Some of the most famous pelycosaurs include Dimetrodon and Edaphosaurus.
The archosaurs were the next group of “mammal-like reptiles” to appear. They were more advanced than the pelycosaurs, and they had a more upright posture. They were also the first animals to develop an amniotic egg, which allowed them to reproduce on land. Some of the most famous archosaurs include the crocodiles, alligators, and dinosaurs.
The therapsids were the last of the “mammal-like reptiles” to appear. They were the most advanced of the three groups, and they were the first animals to develop fur and the ability to chew. They were also the first animals to develop an erect posture and the ability to walk on two legs. Some of the most famous therapsids include the cynodonts and the ancestors of mammals.
These three groups of “mammal-like reptiles” were the dominant terrestrial life forms before the dinosaurs. They were the first animals to develop the ability to regulate their body temperature, the first to have a bony skeleton, the first to develop an amniotic egg, the first to develop fur and the ability to chew, and the first to develop an erect posture and the ability to walk on two legs.
These “mammal-like reptiles” were the predecessors of the dinosaurs, and they were the dominant terrestrial life forms for 120 million years. They were the first animals to develop many of the features that we now associate with mammals, and they were the first to lay the groundwork for the evolution of the dinosaurs.
Although the dinosaurs eventually replaced the “mammal-like reptiles” as the dominant terrestrial life forms, these creatures still had a major impact on the evolution of life on Earth. They were the first animals to develop many of the features that we now associate with mammals, and they were the first to lay the groundwork for the evolution of the dinosaurs. Without the “mammal-like reptiles,” the dinosaurs may never have evolved.
