Ascute is a bony external plate orscale, as on the shell of aturtle, the skin ofcrocodiles or the feet of somebirds.
Scutes are similar toscales and serve the same function. Unlike the scales of fish andsnakes, which are formed from theepidermis, scutes are formed in the lower vascular layer of the skin and the epidermal element is only the top surface. Forming in the livingdermis, the scutes produce ahorny outer layer, that is superficially similar to that of scales.
The dermal base may containbone and producedermal armour. Scutes with a bony base are properly calledosteoderms. Dermal scutes are also found in the feet of birds and tails of somemammals, and are believed to be the primitive form of dermal armour in reptiles.
The term is also used to describe the heavy armour of thearmadillo and the extinctglyptodon, and is occasionally used as an alternative to scales in describing snakes or certain fish, such assturgeon.