Presentation
Turtles (chelonians) have a history that dates back more than 210 million years. The turtle crossed the climate crisis and evolved over time to survive.
Today, there are more than 300 known species of turtles and a multitude of sub-species (over 2000), found in seas, rivers and on land.
The origins of the turtles are no longer any doubt. We know they appeared during the Mesozoic Era (- 315 million years / - 2 million years). However, the exact period has been the subject of controversy. The oldest turtle fossils date back from the middle of the Triassic Period, over 200 million years ago. They come from semi aquatic turtles. But these animals quickly diversified and spread over the entire world.

First turtle
The oldest tortoise known to date is Proganochelys. This is the most primitive turtle, appearing about 210 million years ago.

It is similar to our current turtles with a long tail, a shell consisting of a large number of bones with the difference of having a mouth with teeth and a neck with spades, making it impossible to retract.

Two groups
Shortly after the appearance of the first turtles, we note that two groups identify with each other in particular: Turtles Pleurodires which are unique to retract the neck laterally in the horizontal plane. Cryptodires turtles retract their necks S vertically.

Evolution
From the Cretaceous and until recently there was a kind of large turtles called "Meiolaniidés. They measured up to 2.5 m long. Their heads were fitted with two large horns. This was perhaps the cause of its extinction since it could not get his head into its shell to protect itself from predators.

Meiolania oweni