New fossil finds have the potential to radically change our ideas about what happened to the dinosaurs 66 million years ago.

It’s a summer’s day in 2013, and paleontologist Robert DePalma is digging for fossil remains at a site in North Dakota. Then he suddenly hits pay dirt: a fossilized specimen of a 5-foot paddlefish. What’s more, much to the scientist’s surprise, beneath the remains of the fish is a tooth that belonged to a mosasaur – a massive extinct reptile. But the finds don’t make sense, since the paddlefish lived in freshwater, while the reptile was a sea creature. And DePalma’s explanation of this anomaly will astonish – and divide – the world of paleontology.

If the theory DePalma has come up with to explain the extraordinary jumble of fossils that he’s unearthed at this site near Bowman, North Dakota, is correct, it is academic dynamite. And some previous ideas – particularly ones about the extinction of the dinosaurs – will be confirmed, while others will be debunked forever.

Plus, while DePalma is an interesting and sometimes controversial figure in the sphere of paleontology, his passion for the subject appears to be 100 percent genuine. By his own account, he was just three or four years old when bones started to fascinate him. In an April 2019 interview with The New Yorker, DePalma recalled, “I went after whatever on the dinner table had bones in it.”

The young DePalma’s interest in bones was so intense, in fact, that his family buried deceased pets in one spot but put the grave markers elsewhere to hide the true positions of the remains. Undeterred, DePalma found the real burial spots anyway and began to dig. And attempts to kindle an interest in sport in the boy merely resulted in him excavating the baseball field in a search for further bones.

Years later, though, DePalma’s early obsession had turned into a career. And at that North Dakota dig site in 2013, he believed that what he’d stumbled upon would provide nothing less than a definitive answer to paleontology’s greatest puzzle: why and how had the dinosaurs disappeared from the face of the Earth at the end of the Cretaceous period?

But before we examine in detail what DePalma found and the theories that he’s built around his discoveries, let’s take a quick look at the story of the dinosaurs. To the best of our knowledge, these creatures appeared on our planet roughly 243 million years ago. And a mass extinction event 201 million years ago gave the dinosaurs the opportunity to become the dominant vertebrate animals on our planet.

The predominance of the dinosaurs continued through the Jurassic and Cretaceous periods up until around 66 million years ago. And during the reptiles’ heyday, they dominated the planet. Paleontologists have uncovered dinosaur fossils on every one of the Earth’s continents, in fact, while more than 500 different genera or classes of dinosaur and in excess of 1,000 different species have also been discovered.

Obviously, after all those millions of years, there may be many species that have left no trace. It should be noted, too, that humans have only been looking for dinosaur fossils in an organized way since the late 18th century – the blink of an eye in terms of geological time. And with that in mind, who knows how many more fossils of unknown species are waiting to be discovered?

But all of the non-avian dinosaurs – the ones that didn’t evolve into birds – disappeared altogether around 66 million years ago at the end of the Cretaceous period. Nonetheless, some descendants of the reptiles remain today; the next time you’re feeding ducks, remember that they’re in fact the distant relatives of dinosaurs.

Yes, scientists today are confident that birds are the last evolutionary vestige of the dinosaurs. The director of the Natural History Museum of Los Angeles County, Luis Chiappe, told National Geographic in 2018, “There is no doubt that birds are dinosaurs. The evidence is so overwhelming [that] I would put it next to whether you’re going to question if humans are primates.”

Image: Time Life Pictures/NASA/The LIFE Picture Collection via Getty Images

But all the other dinosaurs are absent entirely from the fossil record after about 66 million years ago. Why? Well, there are competing hypotheses, but perhaps the best known is the catastrophe asteroid impact theory. In effect, this claim supposes that dinosaurs perished after a huge lump of rock crashed into the Earth.

Image: Allie_CUSGS/NASA Landsat data/Orbital Horizon/Gallo Images/Getty images

The asteroid in question plunged towards the Earth at a speed of some 45,000 miles per hour. And as the rock traveled onwards, the super-heated air that preceded it helped forge a hole in the planet’s atmosphere. This force created a supersonic blast even before the asteroid hit Earth, in fact.

And researchers at the Los Alamos National Laboratory have attempted to figure out what would have happened after the missile made its fateful impact. It’s been suggested, for instance, that the asteroid was around six miles wide and that it would have created an 18-mile-deep crater as it hit Earth. That cataclysmic collision, moreover, would have created an explosion a staggering one billion times more powerful than that produced by the atomic bomb that fell on Hiroshima.

The result of this explosion would have been devastating, then, and the destruction would have spread around the world. Some 70 percent of the world’s forests would have burnt owing to the superheated debris that blew into the Earth’s atmosphere and then fell to the ground. A massive tsunami would have smashed everything it encountered, too.

So how do we know that this asteroid really did crash into the Earth 66 million years ago? Well, there are two main pieces of evidence. One of these is a layer of material that paleontologists have found in excavations in many locations around the planet. This sheet of rock contains a rare element called iridium, which scientists believe was present in the asteroid.

What’s more, researchers have found this iridium-containing stratum in rock structures that date back to 66 million years ago. The band of material is commonly called the K-T layer, and it represents the boundary between the Cretaceous period – so, when dinosaurs existed – and the Tertiary period – when they didn’t.

Meanwhile, the second compelling piece of evidence for the asteroid emerged in 1991. That year, a scientific paper was published that described the discovery of a massive crater. The hole in question is located beneath Mexico’s Yucatan Peninsula, which lies between the Caribbean and the Gulf of Mexico in the southeast of the country.

The crater is named after a town that is located nearby, Chicxulub, and it has been dated as being a little less than 66 million years old. And the discovery of the crater greatly reinforced the likely accuracy of the theory that a massive asteroid impact had caused a mass extinction event all those millions of years ago.

Furthermore, it’s been posited that the fallout from the asteroid strike led to the dinosaurs meeting their demise. But not everyone agrees with this theory. Yes, some scientists don’t actually believe that dinosaurs were wiped out solely by this one cataclysmic event; rather, they have asserted that a series of volcanic eruptions negatively impacted the dinosaurs over a longer period of time. And so while the asteroid may have been the last straw for the reptiles, they were already somewhat doomed.

Image: plus49/Construction Photography/Avalon/Getty Images

But regardless of whether the dinosaurs were already in decline when the asteroid hit, there’s still a missing piece of the puzzle when it comes to the catastrophic asteroid extinction theory. Scientists call that conundrum the 3-meter problem. And the 3 meters referred to represent the 10 or so feet of material found just below the K-T layer.

Image: Patrick AVENTURIER/Gamma-Rapho via Getty Images

That 10-foot-thick layer of the Earth’s crust represents the passage of many thousands of years. And if the Chicxulub asteroid caused the sudden extinction of the dinosaurs, there should be fossil evidence of the creatures right up to the level of the K-T layer. Yet even after many years of searching, paleontologists have never found dinosaur fossils in that 10 feet of rock.

Image: DEA / CHRISTIAN RICCI/De Agostini via Getty Images

Nonetheless, defenders of the catastrophic asteroid theory of dinosaur extinction have contended that this seeming lack of remnants in the K-T layer is only evidence of one thing: that dinosaur fossils are hard to locate. These scientists say, in fact, that it’s just a matter of time until a vital discovery is made.

And that brings us back to Robert DePalma, as he claims to have unearthed dinosaur fossils directly below the K-T layer. If his assertion is true, then, that solves the 3-meter problem once and for all. But before we examine DePalma’s theories more closely, let’s take a look at the evidence that he says he’s uncovered and the site where it can be found.

Image: Jonathan Newton/The Washington Post via Getty Images

DePalma found the site on which he has been working for the past few years back in 2012 after a tip-off from a private fossil collector. The location, near Bowman, North Dakota, is on the Hell Creek Formation – a series of rocky outcrops that stretch across Montana, the two Dakotas and Wyoming. And to begin with, the collector felt that the area was unlikely to contain anything of significant paleontological import.

At first, DePalma felt the same way about the site that he was later to dub Tanis. “I was immediately very disappointed,” he told The New Yorker in April 2019. Upon further examination of the site, however, DePalma began to see some potential there. And when he returned to Tanis in July 2013, he eventually noticed something that put the area in an altogether different – and more interesting – perspective.

Digging down, DePalma found a profusion of fossils. And he later described to The New Yorker what he’d unearthed. The researcher explained, “There’s amazing plant material in there, all interlaced and interlocked. There are logjams of wood, fish pressed against cypress-tree root bundles [and] tree trunks smeared with amber. You see skin; you see dorsal fins literally sticking straight up in the sediments – species new to science.”

And during the summer of 2013, he found the paddlefish with the mosasaur tooth that we mentioned earlier. Yet this discovery in itself posed something of a head-scratcher. You see, while paddlefish live in freshwater, mosasaurs were marine-dwelling creatures. As the nearest sea would have been several miles away at a minimum from the site, however, it begged the question: why were these two specimens mixed up together?

DePalma’s puzzling paddlefish and mosasaur find was followed by others that were equally mystifying. And the discovery of tektites – deposits of glass that fall from the sky after a major explosive event such as the Chicxulub asteroid hit – only added to the mystery. But, in time, DePalma felt that he had an answer to the queries surrounding the strange discoveries that he’d made.

“When I saw [the tektites], I knew [that] this wasn’t just any flood deposit,” DePalma told The New Yorker. “We weren’t just near the K-T boundary; this whole site is the K-T boundary!” Perhaps the massive tsunami caused by the asteroid had flooded the area of the Hell Creek Formation – thus creating the weird jumble of specimens that DePalma had unearthed at his site.

DePalma continued, “We have the whole K-T event preserved in these sediments. With this deposit, we can chart what happened the day the Cretaceous died.” And DePalma received some welcome support from one of the world’s most eminent paleontologists: Walter Alvarez. Indeed, The New Yorker reported that Alvarez had declared himself “astounded” after he visited the site in 2018.

Back in 1980 Alvarez had been a member of the team that first identified the K-T layer by the presence of iridium. An endorsement from him, then, was worth its weight in gold. And Alvarez was indeed full of praise for Tanis. He added, “It is truly a magnificent site – surely one of the best sites ever found for telling just what happened on the day of the impact.”

Many of DePalma’s finds have been quite extraordinary, too. For example, he discovered the fossilized remains of an early mammal nestling at the bottom of a burrow that had been preserved in the solidified silt. And DePalma believes that the specimen probably came from a marsupial that resembled a weasel. After the demise of the dinosaurs, you see, mammals came into their own, with our own mammalian species emerging a lot later.

What’s more, DePalma also found a dinosaur fossil at Tanis. This came in the shape of a hip bone from the ceratopsian family of dinosaurs. The ceratopsian that most of us would recognize is the triceratops with its distinctive three horns. And if DePalma was right that his site reflects the events of the hours after the prehistoric asteroid impact, that would solve the 3-meter problem at a stroke. At last, then, a dinosaur fossil had been found right on the K-T boundary – according to DePalma, anyway.

But despite the apparent excitement and approval of such a scientific heavyweight as Alvarez, other paleontologists have been strongly skeptical of DePalma’s claims. And, in fact, DePalma has been involved in controversy before. One notable incident came, for instance, in 2015 in the shape of an unfortunate misidentification.

During that year, DePalma claimed to have unearthed an entirely new type of dinosaur that he’d discovered in the Hell Creek Formation. He had named this creature Dakotaraptor and subsequently presented what he asserted was a reconstructed skeleton. Unfortunately, though, other paleontologists spotted that one of the bones that supposedly made up part of the Dakotaraptor actually belonged to a turtle.

And then there was the way that DePalma had first revealed his discoveries – as well as his claims about Tanis being right on the K-T boundary. You see, news of his finds first hit the public via an article and interview in The New Yorker. Venerable though that magazine certainly is, it is not a scientific journal.

And while a formal scientific paper was published a few days after The New Yorker piece in the Proceedings of the National Academy of Sciences, that only served to encourage further criticism from skeptics. In the New Yorker article, DePalma revealed information that was not included in the scientific journal – including details of his dinosaur finds.

One skeptic is Hell Creek Formation expert and Smithsonian National Museum of Natural History director Kirk Johnson. He told National Geographic, “The weird thing is, DePalma has been very hyperbolic and cryptic for the last six years. The paper is fine, and we can talk about its significance, [but we] have it paired with the New Yorker article, which has a lot more nuanced detail and a lot more claims. It just makes us all a little bit queasy.”

But DePalma’s co-author Phillip Manning, of the U.K.’s Manchester University, has since come to his colleague’s defense. He said to the Science website, “It saddens me that folks are so quick to knock a study.” Mark Richards of the University of California, Berkeley – also a co-author of the paper – added, “That some competitors have cast Robert in a negative light is unfortunate and unfair.”

For now, it’s perhaps best to reserve judgment on DePalma’s work. In fact, we should soon know much more, as it’s reported that several additional scientific papers about the Tanis finds are currently being prepared. And if DePalma’s claims are supported by further evidence, then his discoveries will indeed change our understanding of what happened after the Chicxulub asteroid smashed into Earth.