A new early fish fossil from the Cambrian sediments (approximately 505 million years old) provides some of the earliest evidence for the evolution of the jaw. Whilst the number of living animals with a jaw vastly outnumbers those without (today it is only the lamprey and hagfish that do not have a jaw), it has proven challenging to pinpoint when this feature first evolved. This new fossil, from the world famous Burgess Shale localities in the Canadian Rockies, provides our earliest glimpse of branchial arches, which are bony hoops that support the gills. It is the first of these hoops that is used as a jaw in jawed fish and ultimately all of us vertebrates!
A major fossil discovery in Canada sheds new light on the development of the earliest vertebrates, including the origin of jaws, the first time this feature has been seen so early in the fossil record.