cryptodiran
/ˌkrɪptə(ʊ)ˈdʌɪrən/Zoology and Palaeontology
adjective
Of, relating to, or characteristic of the chelonian suborder Cryptodira (which includes most kinds of turtle, tortoise, and terrapin), characterized by retraction of the head directly backwards into the shell by a vertical flexure of the neck.
noun
= cryptodire.
Origin
Late 19th century; earliest use found in Geological Magazine. From scientific Latin Cryptodira, suborder name (E. D. Cope 1867 or earlier; alteration of Cryptodera from French Cryptodères, subfamily name from crypto- + ancient Greek δειρή (Attic δέρη) neck: see derotremate) + -an.