130-million-year-old Utah fossil could reshape science around Earth's super-continent, Pangea

David DeMille | The Spectrum

The 130-million-year-old skull of a tiny mammal, found amid a set of dinosaur bones after a St. George paleontologist came across a cache of fossils more than a decade ago, could reshape the way scientists think about the breakup of Earth’s ancient super-continent, Pangea, and about the way mammals spread across the world.

The skull, found nearly complete, represents a new species, dubbed Cifelliodon wahkarmoosuch; the latter half translates to “Yellow Cat” in the ancestral language of the Ute tribe. And while it was found in an exposed rock formation on Bureau of Land Management land northeast of Arches National Park, it has some unlikely relatives — a subgroup of creatures known as Hanodontidae, which had previously only been found in regions of North Africa.

In a paper published this month in the scientific journal Nature, lead author Adam Huttenlocker, a paleontologist and assistant professor at the University of Southern California, suggests the discovery means that Pangea broke up into smaller continents about 15 million years later than previously thought. And that would reshape the way scientists think about the early migrations of mammals and their close relatives between Asia, Europe, North America and the southern continents.

“For a long time, we thought early mammals from the Cretaceous (145 million to 66 million years ago) were anatomically similar and not ecologically diverse,” Huttenlocker said in a written statement. “This finding by our team and others reinforce that, even before the rise of modern mammals, ancient relatives of mammals were exploring specialty niches: insectivores, herbivores, carnivores, swimmers, gliders. Basically, they were occupying a variety of niches that we see them occupy today.”

Introducing a new species

The skull, now on display at the Natural History Museum of Utah, was found amid a cache of dinosaur fossils uncovered by paleontologists with the Utah Geological Survey.

Its makeup, combined with existing knowledge of its relatives, indicates Cifelliodon would have been about six inches long and weighed about 2.4 pounds, covered with fur and with a shallow snout and downturned face. It would have suckled its young like modern mammalia, but laid eggs like the platypus and echidna.

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Its broad molars suggest a diet of leafy vegetation, and a reconstruction of its brain using CT scans of the skull suggest it had large olfactory bulbs and would have had an excellent sense of smell. This also means it was likely nocturnal.

It is the first mammal skull found in Utah’s Cretaceous-period rocks, and comes from a group of primitive mammal relatives known as the Haramiyida, which had previously not been found in either the Cretaceous or North America.

It is notably younger than related Jurassic-era mammals found in Eurasia and North Africa.

The fossil, with its European ties, adds an important point of collaboration with newly discovered European dinosaur groups from the same kinds of rock, indicating they were left at a time when the Atlantic Ocean had not fully opened.

A loaded discovery

The fossil represents the latest science to come out of Utah’s Cedar Mountain Formation, an Emery County geologic wonder providing troves of new information to paleontology.

It was discovered almost by accident inside a lab while scientists were working to extract the dinosaur bones that surrounded it.

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The collection, taken from a site discovered by Andrew Milner, the paleontologist and curator at the Dinosaur Discovery Site at Johnson Farm in St. George, has so far yielded fossils from five creatures, including three dinosaurs and a crocodilian that is still being researched.

Milner said he initially saw dinosaur bones at the site when he was first there in 2004, but when he returned later they were gone, apparently removed illegally.

Luckily, he had showed the site to James Kirkland, the state paleontologist with the Utah Geological Survey.

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“(Kirkland) came back with a couple of geologists to talk about the formations there, just the geology, and he happened to be standing on that exact site and found bones weathering out all over the place,” Milner said.

Two large blocks of rock were taken to a laboratory, where fossils from two large iguanodontian dinosaurs were studied. Beneath the foot of one of them was the Cifelliodon skull.

Among those helping with the dig were St. George area volunteers Bob and Linda Baldazzi, Steve and Sally Stephenson, David Slauf and Tylor Birthisel, a former Discovery Site intern.

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Kirkland said the site has yielded important discoveries already, but could likely produce more as work continues on the other fossils.

“The same geology that gave us Arches National Park gave us this basin that totally surrounds Arches, that loops all the way around it, and that gives us all these dinosaurs,” he said.

“We’ve been finding dinosaur on top of dinosaur,” he added.

Follow David DeMille on Twitter, @SpectrumDeMille.

What's in a name?

Cifelliodon wahkarmoosuch, the name of the new mammalian species, means “Cifelli’s tooth of the Yellow Cat,” honoring Oklahoma paleontologist Richard Cifelli for his contributions to the Cretaceous mammal research in Utah and the American West, and using the Ute tribal words for yellow, “wahkar,” and for cat, “moosuch.”

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