Testudines

Testudines, or Chelonii are an order of reptiles comprised of turtles and tortoises. They are characterised by a special bony or cartilaginous shell developed from their ribs and acting as a shield. The order Testudines includes both extant (living) and extinct species. The earliest known turtles date from 220 million years ago, making turtles one of the oldest reptile groups and a more ancient group than lizards, snakes or crocodilians. Of the many species alive today, some are highly endangered.