 A linear extrapolation from the gill basket would be flawed because the gills grow disproportionally in size, having to increase their surface allometrically to ensure the oxygen supply of a body increasing in volume to the third power.The growth ring structures within the remains of "Leedsichthys" have indicated that it would have taken 21 to 25 years to reach these lengths, and isolated elements from other specimens showed that a maximum size of just over  is not unreasonable.In 2013 a new study by Liston found most specimens to be between 17 and 31 years old.