<P> The carapace is the dorsal ( back ) , convex part of the shell structure of a turtle , consisting of the animal 's ossified ribs fused with the dermal bone . The spine and expanded ribs are fused through ossification to dermal plates beneath the skin to form a hard shell . Exterior to the skin the shell is covered by scutes , which are horny plates made of keratin that protect the shell from scrapes and bruises . A keel , a ridge that runs from front to the back of the animal is present in some species , these may be single , paired or even three rows of them . In most turtles the shell is relatively uniform in structure , species variation in general shape and color being the main differences . However the soft shell turtles , pig - nose turtles and the leatherback sea turtle have lost the scutes and reduced the ossification of the shell . This leaves the shell covered only by skin . These are all highly aquatic forms . </P>
<P> The carapace is the dorsal ( back ) , convex part of the shell structure of a turtle , consisting of the animal 's ossified ribs fused with the dermal bone . The spine and expanded ribs are fused through ossification to dermal plates beneath the skin to form a hard shell . Exterior to the skin the shell is covered by scutes , which are horny plates made of keratin that protect the shell from scrapes and bruises . A keel , a ridge that runs from front to the back of the animal is present in some species , these may be single , paired or even three rows of them . In most turtles the shell is relatively uniform in structure , species variation in general shape and color being the main differences . However the soft shell turtles , pig - nose turtles and the leatherback sea turtle have lost the scutes and reduced the ossification of the shell . This leaves the shell covered only by skin . These are all highly aquatic forms . </P>
the dorsal part of a turtle 's shell is called the
the dorsal part of a turtle 's shell is called the
carapace
carapace