Thaindian News

Washington, Feb 19 (ANI): Scientists have identified 170 million year old fossils as belonging to SUV-sized filter-feeding fishes that emerged during the Jurassic Period, 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.

It can help to have a big mouth, which many of these enormous fishes must have had.

Co-author Kenshu Shimada, a research associate in paleontology at the Sternberg Museum of Natural History, told Discovery News that one of the fish he and his colleagues identified, Bonnerichthys, grew to around 20 feet in length and swam through a seaway covering what is today the state of Kansas.

“A previously described species, Leedsichthys, from the Jurassic of Europe that belongs to the same lineage that includes Bonnerichthys was even larger, likely reaching up to about 30 feet, which is the most massive bony fish of all time,” added Shimada.

For the study, led by University of Oxford scientist Matt Friedman, the researchers analyzed both old and new fish fossils found in England, the US and Japan.

The Kansas fish was previously thought to have been like a gigantic swordfish, bearing fang-like teeth on its jawbones.

“However, our close examination of the specimen showed that such a long snout and fang-like teeth were not present in the fish,” Shimada said.

“Rather, with a blunt massive head, the fish had long toothless jawbones and long gill-supporting bones that are characteristic of plankton-feeding fishes,” he added.

While this fish, and the other Dinosaur-Era filter feeders, enjoyed a long existence on the planet, they were no match for the K-T extinction event that killed off 70 percent of all species then living on Earth. (ANI)