This is interesting, actually causes one to ask more questions than we have answers for.
Such as: Volcanic areas are not common, they are wide-spread - and as they produduce an island eventually - they are relatively short lived. So, where do these creatures come from? I would ‘think’ they would be attracted to the volcanic activity due to nutrients, minerals and the warmer water - as well as the fact that the increased temperatures may create a haven in which they are free from predators. I just can’t imagine that these new lifeforms we are finding there - spontaneously evolved - at that site.
Still, interesting stuff ...
My understanding is that larvae or eggs released by tha creatures are carried upwards by the superheated water. At a lower depth the water cools, the eggs are carried laterally by ocean currents before dropping back into the depths. If they are fortunate,they find another vent to colonise. If not, well......that’s life.
I’ve wondered that myself. Crabs at least have a planktonic stage in their lifecycle....so perhaps their young larvae travel around for a while seeking out such vents?
-——So, where do these creatures come from?——
They evolve from existent species