- Gigantic filter-feeding fishes lived during the Mesozoic Era.
- Filter feeding didn’t first emerge in whales, as had been previously suspected, but instead began with the now-extinct fishes.
- After the filter-feeding fishes died out with the dinosaurs, whales and other cetaceans filled the ecological niche.
Whales include the world’s largest animals, but newly identified fossils reveal they were preceded by SUV-sized filter-feeding fishes that emerged during the Jurassic Period, 170 million years ago, and lived until the extinction event that wiped out dinosaurs and numerous other species.
Although the now-extinct fishes, called pachycormiforms, were not closely related to whales, their demise left an ecological niche void that whales, sharks and rays filled starting around 56 million years ago, helping to explain the top portion of today’s marine food chain.
The fish fossils also prove that filter feeding emerged long before the first whales. For this method of eating, the diner suspends itself in the water, mouth agape. Water escapes through gill slits, leaving behind the filtered food.
Bonnerichthys, grew to around 20 feet in length and swam through a seaway covering what is today the state of Kansas.