The findings might help settle an important debate among biologists.
Today, ray-finned fish make up 99% of all fish species, but it wasn’t always like this. In an attempt to find out what triggered this spectacular multi-niche dominance, paleontologists traveled back in time sort of speak and analyzed ancient fossils to see what the fish diversity makeup looked like millions of years ago. Intriguing enough, the ray fish practically exploded in their diversity right after the last great mass extinction which occurred 65 million years ago. An asteroid impact wiped out thousands of species, including all dinosaurs. But there was now enough room for other creatures to take their place. On land, mammals started filling in the large-scale niches eventually reaching a dominant position. In the water, it was the ray-finned fish that seized the opportunity.
Based on fossil evidence and genome analysis, scientists know that the two groups diverged from a common ancestor around 420 million years ago, but we’ve yet to find actual fossil of it. Things are shaping up though after paleontologists have identified an Early Devonian fish from Siberia, approximately 415 million years old, which bears features of both classes.