Acanthodians are not at all shark-like in shape, for example they have diamond-shaped scales and spines in front of all the fins,' says Emma. 'But they do have a cartilage skeleton, a shark-like skull ...

Teeth are also the hardest part of a shark's skeleton. While our bones are coated in the mineral calcium phosphate, shark skeletons are made entirely from softer cartilage like our nose and ears. So ...

with 510 species of shark and 650 species of ray, what do they really have in common? They both have a skeleton made of cartilage, similar to what human ears and noses are made of. It’s strong ...