Cryptodira (suborder)

Cryptodira is a suborder of turtles characterized by their unique neck movement. Unlike other turtles that bend their neck sideways, cryptodires retract their head straight back into their shell by bending their neck in a vertical S-shaped curve. This adaptation helps them hide quickly from predators and is common in most turtle species, including many freshwater and marine turtles. Cryptodira includes well-known groups like old-world pond turtles, snapping turtles, and sea turtles. Their specialized neck movement is a key feature that distinguishes them within the broader turtle family.