Scientists believe they have discovered a giant fish that grew up to 52ft long – longer than an Olympic-sized swimming pool.
Fossils show the huge plankton-eating creature called Leedsichthys lived 160 million years ago but was wiped out at the same time as the dinosaurs.
Researchers from the University of Bristol believe the bony fish could grow to around nine metres in 20 years but after 38 years it would reach 16.5 metres long, outgrowing today’s whale sharks.
The species was first discovered in 1886 by Alfred Nicholson Leeds.
However, it was difficult to work out the fish’s exact length because fossils were only found in small fragments.
The researchers have now been able to piece samples together to tell how long the creature was by the position of its gills.
The creature is thought to have weighed 21.5 tonnes – the same as two double-decker buses or three African elephants.
The fish, which would live for around 40 years, had an enormous mouth which acted as a hoover to suck up thousands of small fish including shrimps and jellyfish.
Professor Jeff Liston of the University of Kunming in China and the University of Bristol’s School of Earth Sciences said: ‘Leedsichthys skeletons preserve poorly, often only as isolated fragments, so previous size estimates were largely historical arm-waving exercises.
‘The existence of these large suspension-feeding fish at this time is highly significant as it would seem to be clear evidence of a major change in plankton populations in the oceans of Jurassic Earth.
‘This has implications for our understanding of biological productivity in modern oceans and how that productivity has changed over time.
‘We looked at a wide range of specimens, not just the bones but also their internal growth structures – similar to the growth rings in trees – to get some idea about the ages of these animals as well as their estimated sizes.’
‘One of the truly fascinating aspects of this fish as a suspension feeder is that it seems to have developed a unique mesh structure on its gills to help it extract plankton as the seawater passed through its mouth.
‘Extremely delicate and rarely-preserved, it resembles the honeycomb pattern in a bee-hive.
‘It functioned like a trawler’s net to trap plankton, and obviously was very effective, given the large sizes this animal achieved.
‘This mesh structure is very different to what we see in today’s suspension-feeding fish and whales. It had a unique way of solving a similar problem.’
The longest living bony fish is the Oarfish which can grow up to 17m in length (55ft).