lepidosaurian

References

Images

Diagram illustrating the evolutionary stages of turtle shell development, showing skeletal outlines of Eunotosaurus, Pappochelys, Odontochelys, and Proganochelys with red highlighting the expanding shell area over time. Below, side-by-side illustrations compare the body structure and stride length of early reptiles with flexible spines and fast crawling to Eunotosaurus and later turtles with rigid spines and slower movement.

lepidosaurian: Media

reptile subclass

Images

Diagram illustrating the evolutionary stages of turtle shell development, showing skeletal outlines of Eunotosaurus, Pappochelys, Odontochelys, and Proganochelys with red highlighting the expanding shell area over time. Below, side-by-side illustrations compare the body structure and stride length of early reptiles with flexible spines and fast crawling to Eunotosaurus and later turtles with rigid spines and slower movement.

turtle shell evolution

Broad-ribbed bony structures likely evolved to provide early turtles with more stability...

Encyclopædia Britannica, Inc./Eliana Tobin