Scientists claim they've found a perfectly preserved dinosaur fossil killed when the mass extinction asteroid hit the earth 66 million years ago

• Several incredibly well-preserved dinosaur fossils were uncovered at Tanis, a site in North Dakota.
• Scientists believe the dinosaurs died the day a giant asteroid hit the earth 66 million years ago.

Scientists claim to have found a fossil of a dinosaur killed on the day an extinction asteroid struck the Earth 66 million years ago.

Scientists say that the perfectly preserved leg of a Thescelosaurus dinosaur, complete with scaly skin, can be dated back to the mass extinction event because of the presence of debris from the impact, the BBC said.

It is widely believed that when the 7.5 mile-wide asteroid, approximately the size of Mount Everest, hit the Gulf of Mexico, all non-avian dinosaurs on earth were wiped out.

An upcoming BBC documentary looks at a slew of fossils found at the Tanis site in North Dakota. It includes the Thescelosaurus leg, seen in a video here, and the skin of a triceratops, pictured above.

The site is rich in well-preserved fossils, including fish, a turtle, and even the embryo of a flying pterosaur encased in an egg.

Scientists believe that tiny glass-like particles of molten rock lodged in the gills of fish fossils found at the site were kicked up by the asteroid's explosive impact, the BBC said.

"We've got so many details with this site that tells us what happened moment by moment. It's almost like watching it play out in the movies," Robert DePalma, a graduate student from the University of Manchester, UK, who leads the Tanis dig, told the BBC.

Prof Phil Manning, DePalma's Ph.D. supervisor at Manchester, told BBC Radio 4's Today program that the discovery was "absolutely bonkers" and something he "never dreamt in all my career."

"The time resolution we can achieve at this site is beyond our wildest dreams. This really should not exist, and it's absolutely gobsmackingly beautiful," Manning said.

The documentary, which David Attenborough presents, was filmed over three years and will be released on April 15.

A discovery so 'fabulous' it has attracted skepticism

In the BBC documentary, Robert DePalma, a relative of film director Brian De Palma, can be seen sporting an Indiana Jones-style fedora and tan shirt.

He christened the paleontological site "Tanis," the last resting place of the Ark of the Covenant in the 1981 film "Raiders of the Lost Ark," per The New Yorker.

The findings from Tanis, and the work of DePalma, have attracted controversy over the years.

The New Yorker first wrote about the Tanis site in 2019 before presenting the findings in an academic journal.

While paleontologists usually cede their rights and curation of the fossils to institutions, DePalma, who had collected few academic laurels until the discovery of the site, insists on contractual clauses that give him oversight over the specimens. He has controlled how the fossils are presented, per The New Yorker.

In response to the article, Kate Wong, science editor of Scientific American, said in a 2019 tweet that the findings from the site "have met with a good deal of skepticism from the paleontology community."

A few peer-reviewed papers have since been published, and the BBC said that the dig team promises more.

The BBC also said that it has called outside consultants to verify the specimens.

Prof Paul Barrett from London's Natural History Museum looked at the leg and said it was a Thescelosaurus that likely died "more or less instantaneously."

"It's from a group that we didn't have any previous record of what its skin looked like, and it shows very conclusively that these animals were very scaly like lizards. They weren't feathered like their meat-eating contemporaries," Barrett told the BBC.

However, Prof Steve Brusatte, an outside consultant on the documentary from the University of Edinburgh, told the BBC he was skeptical about the dinosaurs' findings for now and would like to see the hypotheses being subjected to the scrutiny of peer review.

"Those fish with the spherules in their gills, they're an absolute calling card for the asteroid. But for some of the other claims — I'd say they have a lot of circumstantial evidence that hasn't yet been presented to the jury," he said.

Prof Brusatte said that it is possible that some of the animals died before the asteroid strike but could have been exhumed and then buried again by the impact.

But ultimately, Brussate said the quality of the fossils trumps the controversy about the event's timing.

"For some of these discoveries, though, does it even matter if they died on the day or years before? The pterosaur egg with a pterosaur baby inside is super-rare; there's nothing else like it from North America. It doesn't all have to be about the asteroid."