NEWSWEEK - Ancient underwater volcanic eruptions may have made modern day sharks more fierce then their predecessors, a new study has found.
The infamous shark species we know of today evolved from stubby bottom dwellers around 93 million years ago when a spew of lava poured into the ocean, the study reported. This caused carbon dioxide levels to soar. This meant a drastic change in climate, making the ocean temperatures hotter than they had ever been.
And now, scientists have found that this was how some sharks developed their pectoral fins. They reached their findings by measuring over 500 sharks, and fossilized shark species, and published them in the journal Current Biology.
"The pectoral fins are a critical structure, comparable to our arms," University of California, Riverside doctoral student and the paper's first author Phillip Sternes said in a statement. "What we saw upon review of a massive data set, was that these fins changed shape as sharks expanded their habitat from the bottom to the open ocean.