A fossil originally thought to be a plastic replica has been found to be a 189 million-year-old genuine relic...thanks to a Manchester dinosaur expert.

The prehistoric sea animal ichthyosaur fossil had been gathering dust in the Doncaster Museum and Art Gallery collection for more than 30 years.

But when University of Manchester palaeontologist Dean Lomax first looked at the fossil in 2008, he noticed several abnormalities, which encouraged him to search deeper into its origins and convince him it was no replica.

And after years of tireless work, collaborating with Prof Judy Massare from New York, and travelling the world in the name of research, Dean has finally revealed the ichthyosaur’s true secrets.

Dean, 25, said: “After examining the specimen extensively, both Professor Massare and I identified several unusual features of the limb bones that were completely different to any other ichthyosaur known.

“That became very exciting and after examining more than a thousand specimens, we found four others with the same features as the Doncaster fossil.”

The fossil dates back to the Triassic, Jurassic and Cretaceous periods, when the ichthyosaurs swam the seas of the earth for million of years.

But after the geologist at Doncaster museum left a few years after the fossil was purchased in 1983, the priceless wonder was confused for a replica.

Now, funding from the Esmee Fairbairn Foundation means Dean’s ground-breaking research will see the prehistoric wonder appreciated for its true value.

And with contents of the animal’s last meal still visible in the stomach, the Doncaster gem has also been named the world’s most complete fossil of its kind.

Dean, an Honorary Scientist at the University of Manchester, said: “We even know what the last meal it ate was before it died because we found some hooklets, which are the hard remains of a squid’s tentacles.”

Dean worked with Professor Judy Massare of Brockport College, New York, and researched the size and age of the new species, looking at sexual differences between males and females.

He added: “The recognition of this new species is very important for our understanding of ichthyosaur species diversity during the early Jurassic period.”

The new species has been named Ichthyosaurus Anningae, in honour of the British collector, Mary Anning, who first collected ichthyosaurus in the early 1800s.

Dean said: “It is an honour to name a new species, but to name it after somebody with such an important role in helping to sculpt the science of palaeontology is something I’m very proud of.”