Lampreys have ‘fight or flight’ cells, challenging ideas about nervous system evolution

These sympathetic nervous system cells were thought to be lacking in jawless vertebrates

lamprey

Even though lampreys look primitive, a new study found signs that their peripheral nervous system is more complex and more similar to that of humans than researchers previously thought.

T. Lawrence, Great Lakes Fishery Commission (CC BY-SA 2.0 DEED)

With terrifyingly sharp teeth arranged around a circular mouth, lampreys look about as primitive a vertebrate as you could imagine.