Osteoderms are bony deposits forming scales, plates or other structures in the
dermal layers of the
skin. Osteoderms are found in many groups of
extant and
extinct reptiles and
amphibians, including
lizards,
crocodilians,
frogs,
temnospondyls, various groups of
dinosaurs (most notably
ankylosaurs and
stegosaurians),
phytosaurs,
aetosaurs,
placodonts, and
hupehsuchians (marine reptiles with possible
ichthyosaur affinities).