Roughbacks are the raised parts on the back of a turtle or a fish.
Roughbacks are a natural part of the animal's body and help to protect them.
Examples:
The turtle has roughbacks on its shell.
The fish's roughbacks help it swim faster.
I touched the turtle's roughbacks.
The roughbacks on the fish look like little bumps.
The turtle's roughbacks are like a shield.
The fish's roughbacks feel bumpy when you touch them.