When was the first reptiles

At first, synapsids were more successful than sauropsids. They became the most common vertebrates on land. However, during the Permian mass extinction million years ago, most synapsids went extinct. Their niches were taken over by sauropsids, which had been relatively unimportant until then. This is called the Triassic takeover. By the middle of the Triassic about million years ago, sauropsids had evolved into dinosaurs. Dinosaurs became increasingly important throughout the rest of the Mesozoic Era, as they radiated to fill most terrestrial niches.

This is why the Mesozoic Era is called the Age of the Dinosaurs. During the next mass extinction, which occurred at the end of the Mesozoic Era, all of the dinosaurs went extinct.

Many other reptiles survived, however, and they eventually gave rise to modern reptiles. Figure below shows a traditional phylogenetic tree of living reptiles. Based on this tree, some of the earliest reptiles to diverge were ancestors of turtles. The first turtle-like reptiles are thought to have evolved about million years ago.

Ancestral crocodilians evolved at least million years ago. Tuataras may have diverged from squamates snakes and lizards not long after that. Finally, lizards and snakes went their separate ways about million years ago. Today, the only living relatives of the anapsids are turtles and tortoises , though the exact nature of this relationship is hotly disputed by paleontologists.

The synapsids spawned one extinct reptilian line, the pelycosaurs, the most famous example of which was Dimetrodon , and another line, the therapsids, which evolved into the first mammals of the Triassic Period. Finally, the diapsids evolved into the first archosaurs, which then split off into dinosaurs, pterosaurs, crocodiles, and probably marine reptiles such as plesiosaurs and ichthyosaurs. What's of interest here is the obscure group of lizard-like reptiles that succeeded Hylonomus and preceded these better-known and much larger beasts.

It's not that solid evidence is lacking; plenty of obscure reptiles have been discovered in Permian and Carboniferous fossil beds, especially in Europe. But most of these reptiles look so similar that attempting to distinguish between them can be an eye-rolling exercise. Classification of these animals is a matter of debate, but here's an attempt to simplify:.

Finally, no discussion of ancient reptiles is complete without a shout-out to the "flying diapsids," a family of small Triassic reptiles that evolved butterfly-like wings and glided from tree to tree. True one-offs and well out of the mainstream of diapsid evolution, the likes of Longisquama and Hypuronector must have been a sight to see as they fluttered high overhead. These reptiles were closely related to another obscure diapsid branch, the tiny "monkey lizards" such as Megalancosaurus and Drepanosaurus that also lived high in trees but lacked the ability to fly.

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Select basic ads. Create a personalised ads profile. Select personalised ads. Researchers of this study also included Pierce, the Thomas D. In the U. The scientists believe that by understanding how animals evolve over longer periods of time, they can glean a number of lessons on ecology and how organisms are affected by environmental changes. Using the database, researchers can determine when major reptile lineages or morphologies originated, see how those changes affected reptile DNA, and learn important lessons about how species were impacted by historical events.

Reptiles, for instance, have survived three major mass extinction events. The timeline researchers created found that the rates at which reptiles were evolving and the anatomical differences among them before the Great Dying were nearly as high as after the event.

However, it was only much after the Great Dying that reptiles became dominant in many ecosystems and extremely diverse in terms of the number of different species. New evidence shows the evolution of the first building blocks on Earth may have been messier than previously thought. The researchers also note that it took reptiles almost 10 million years to recover to previous levels of anatomical diversity.

They also underwent rapid changes to their skulls about to million years ago that led to such powerful and flexible mouths that today they can swallow whole prey many times their size.