Prior to now, it has been accepted as common knowledge that cartilaginous fish predate bony fish in the ancient parts of the evolutionary family tree. As a result, it has been generally assumed that the earliest fish with jaws would have something fairly closely resembling that of a shark, as sharks are accepted to be on of the most ancient of vertebrates. However, the recent discovery of Entelognathus Primordialis in China may cause us to question these long held beliefs and assumptions.
This armored, toothless fish, may be up to 419 Million years old. Making it one of, if not the earliest vertebrate to be discovered to date, and it’s discovery throws a wrench in our image of what our prehistoric ancestors looked like. Entelognathus, rather than being a sleek, sharklike cartilaginous fish, is bony, with many small plates making up it’s skull and jaw. This skeletal template is something found in all land-dwelling vertebrates in modern day, leading scientists to theorize that rather than bony skeletons evolving from cartilaginous ones. it may have happened the other way around. Making our armored ancestors potentially more ancient than sharks’ more scaly predecessors.