Talk:Rockgrub/@comment-35507650-20180506120315/@comment-35507650-20180507014744

Tortoises have an osteodermic carapace comprised of an (admittedly superficial) endoskeletal dorsal/costal (rib+back) structure and an exodermic surface comprised of scutes. The skeletal structure of a tortoise's shell develops from within deep tissue - not from without, like a mollusk's shell or arthropod's chitin. Saying they have an exoskeleton is a misuse of terms; commonly done, but still inaccurate.