Turtle
The earliest known fully shelled turtles are the late Triassic Odontochelys, Chinlechelys and Proganochelys. The first-named genus was aquatic (lived in water), but the second was probably terrestrial (lived on land). They already had many advanced turtle traits, and probably had millions of years of turtle evolution and species in their ancestry. They had a long neck and could not pull their heads into their shell. Odontochelys had a long, spiked tail ending in a club. Ankylosaurs also have these traits because of convergent evolution.