Oct. 26 (UPI) -- Fish likely evolved from shallow shorelines, dating back more than 400 years ago, according to scientists.
New findings were published in Science magazine Friday on the evolution of vertebrae fish during the middle Paleozoic era, from 480 million to 360 million years ago.
The study was conducted by a team of researchers from the University of Pennsylvania, University of Michigan, University of Manchester and University of Birmingham.
The team focused primarily on fossil vertebrates, both jawed and jawless fish. Scientists found that larger fish diversified near shorelines, and later thinner fish populated deeper marine and freshwater habitats.
Their goal was to "complete a missing link in our evolutionary story" by closing some of the gaps of what researchers knew about that time.
"It's been this ongoing question of, well, where were they?" Lauren Sallan, a paleobiologist at the University of Pennsylvania and the lead researcher of the study told PennToday. "Where were they hiding? What were their environmental origins?"
The team produced a database of more than 2,700 fossil records of jawless and jawed fish from every continent. The team then used database to figure out which ocean the early fish group habitats came from.
"One reason why these fossils have been hard to study is precisely because of the area in which they are found. Wave action in the shallow ocean area likely blasted them into tiny fragments," Sallan said.
This recent discovery contradicts previous findings that the evolutionary habitat of fish began in deep water near coral reefs.
As time went on, fish with thinner body types could maneuver farther out to deep waters. While fish with bulkier body types, unable to navigate those rougher waters, were restricted to shallow waters.
"In modern conceptions, we see that coral reefs are so important for fish biodiversity, so we assume there's an ancient link between fishes and reefs going back to the beginning," Sallan said. "But decades of searching in places like the Cincinnati Arch have come up empty."