They are among the most primitive of the ray-finned ... Like many of the other living fossil fish, the bichir is especially adapted to life in dry environments. Instead of a regular swim bladder ...

Sharks have roamed the open seas for close to half a billion years and have witnessed the Earth’s evolution from a primordial ...

Fish appear in the fossil record before four-legged animals (tetrapods), so the ancestor of this group must be at least as primitive as a fish. The most ancient fish were jawless, and since our ...

"Even though acanthothoracids are among the most primitive of all jawed vertebrates, their teeth are in some ways far more like modern ones than arthrodire dentitions. Their jawbones resemble those of ...