Which was one of the first and most successful animal class of gnathostomes animals that have jawed mouths?
Which was one of the first and most successful animal class of gnathostomes animals that have jawed mouths? The acanthodians’ jaws are presumed to have evolved from the first gill arch of some ancestral jawless fishes that had a gill skeleton made of pieces of jointed cartilage. The common name “spiny sharks” is really a […]