It was thought collagen was a relatively recent invention in...

It was thought collagen was a relatively recent invention in vertebrate evolution that unites us with reptiles, amphibians, sharks and bony fishes, while the lamprey skeleton was based on quite different proteins. Knowing that lampreys also use collagen to build their skeletons makes sense. Lampreys and jawed vertebrates inherited the same genetic program for skeletal development from our common ancestor.