For more than a century, the mystery of the true size of a gigantic dinosaur-era fish, Leedsichthys, seemed like the one that got away for paleontologists.
However, a new study may have solved the problem. The study documented an ancient whopper Leedsichthys that may be the largest fish ever found at 16.5 meters (54 feet). The longest living fish, a whale shark, ever documented stretched 12.7 meters (41.5 feet).
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The Jurassic giant, Leedsichthys problematicus, received its name because scientists couldn't estimate the true size of the fish. Fossil hunters uncovered the first Leedsichthys fossils in the late 1800s. The fish's remains later turned up as far apart as England and Chile.
However, much of the skeleton of Leedsichthys, including the vertebra needed to know the animal's length, was made of cartilage. Cartilage doesn't fossilize easily, so paleontologists had to guess from the bones of the skull, gills, fins and a few other parts.
The problem was that the gills of the fish would have grown proportionately larger than the rest of the fish, because of the gills' need to absorb enough oxygen, according to a 2005 study by Jeff Liston of the National Museums Scotland. Therefore, estimates from the size of the gills couldn't be trusted.