there used to be a shark like being with a buzzsaw like jaw, called helicoprion
This little fella. Scientists were confused for a while as they assumed the fossil they found would attach to their dorsal fin and/or tail, which was disproven some time later where they figured out by the remains that the fossil of teeth (because a lot of shark scales are also made of the same thing as their teeth) were meant to be inside of the mouth and not on their outer body.
the teeth have been assumed to have been for breaking hard bodied prey
they also technically weren’t sharks
Guys this is cool look











