Paleontologists stunned by a perfectly preserved dinosaur footprint discovered by a 4-year-old girl

• A four-year-old girl found a dinosaur footprint on a beach in Wales that dates back 220 million years.
• The print was most likely left by a small and slim dinosaur that walked on its two hind feet.
• Experts are calling it "the finest impression of a 215 million-year-old dinosaur print" found in a decade.

A four-year-old girl stunned paleontologists after she found a perfectly-preserved dinosaur footprint that dates back 220 million years.

Lily Wilder made the discovery on January 23 while walking along a beach in South Wales with her father and dog. The family was on their way to the supermarket when Wilder saw the footprint imprinted on a rock.

"It was on a low rock, shoulder height for Lily, and she just spotted it and said, 'look, Daddy,'" her mother, Sally Wilder, told NBC News. "She is really excited but doesn't quite grasp how amazing it is."

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At first, the family thought the print, which is just over 10 cm (4 inches) long, was scratched out on the rock by an artist.

But mother Sally was aware that similar footprints had been found along that piece of the coast before, so she posted about their discovery on social media.

"I found this fossil identification page on Facebook and I posted it on there and people went a bit crazy," she told Wales Online.

Shortly after, The National Museum of Wales was in touch with the Wilder family, and officials have since retrieved the print and put it in the museum.

Experts believe the footprint was most likely left by a dinosaur that stood about 75 centimeters (29.5 inches) tall and 2.5 meters (about 8 feet) long and walked on its two hind feet.

It is impossible to identify exactly what type of dinosaur left it, although experts typically classify the print as a Grallator.

Welsh scientists are calling the girl's discovery "the finest impression of a 215 million-year-old dinosaur print found in Britain in a decade," according to Wales Online.

"It's so perfect and absolutely pristine. It's a wonderful piece," said Karl-James Langford from Archeology Cyrmu, according to Wales Online.

"I would say it's internationally important and that is why the museum took it straight away. This is how important it is. I would say it's the best dinosaur footprint found in the UK in the past 10 years," he added.

The family says their daughter's interest in dinosaurs has been ignited since the discovery and that she's been playing with a collection of dino toys and models.

The National Museum in Cardiff, which is currently closed due to the COVID-19 pandemic, said that Lily and her classmates would be invited to the exhibition once it reopens.

"What's amazing is, if her name goes down as the finder in the museum, it could be her grandchildren going to visit that in the museum one day, and for years and years and generations to come, which is quite amazing," mother Sally told Wales Online.