Sea Once Filled With 'Dino Fish' Giant fish prowled oceans in dinosaur age By Rob Quinn, Newser Staff Posted Feb 19, 2010 5:26 AM CST 1 comment Comments The ancient 'dinosaur fish' gave way to creatures like the manta ray and the whale shark. (Shutter Stock) (Newser) – Scientists have discovered a "missing link" in evolutionary history: evidence that prehistoric seas were filled with enormous, plankton-eating fish. The dino-sized fish existed between 66 and 172 million years ago, dying out around the the same time as the dinosaurs. It was only after they vanished that mammals and cartilaginous fish— like the manta ray and whale shark—adapted to fill their ecological niche. The research, published in Science, looked at what was thought to be the sole example of a filter feeder in dino times. Subsequent trips to museums and research centers around the world found evidence of similar fossils in much younger rock, proving that filter feeders were around for much longer than previously thought, the BBC reports.