Some previously mis-identified fossils have recently been used to describe a “New” giant prehistoric filter feeding fish. It’s been known for many years that prehistoric filter feeding fish called Pachychormids had existed, but paleontologists believed these to be a short lived (20 million years) group of fishes. What is exciting about the description of these forgotten pachychormid fossils is that they are dated at 66 million and 172 million years, meaning that the giant filter feeding fish may have existed for more than a hundred million years.
One genus of giant filter feeding fish, Leedsichthys, may have grown to 50 feet. At this scale the giant filter feeders occupied the ecological niche of filter feeding whales, sharks and manta rays until they were wiped out by the Cretaceous-Paleogene mass extinction which also took out the dinosaurs. If the pachychormids had survived but still become displaced by whales and sharks, perhaps they may have adapted to become smaller, dainty filter feeding reef fish which we keep in our aquariums today. Oh well, there’ still filter feeding sardines.