America has cultivated a reputation as being a place that offers new beginnings, especially when times get tough elsewhere—but now paleontologists think that tradition may actually date back 140 million years, to the days when dinosaurs roamed the Earth. That's because they realized two dinosaurs dug out of the rocks of Utah bear a strange resemblance to a family that had only been spotted in Europe and Africa previously.
That makes them think the immigrants made use of a temporary land bridge to colonize new territory, in the process evading (or at least delaying) the extinction that wiped out their Old World relatives. The team of paleontologists announced their find in a paper recently published in the journal Scientific Reports. In the paper, they describe the movements of a group of dinosaurs called turiasaurs, which were vegetarians and had long, giraffe-like necks.
In particular, the paleontologists identify a new species of turiasaur, based on specimens found a bit northeast of Arches National Park. Their picture of the new species, now named Mierasaurus bobyoungi, is based in particular on three legs of a still growing dinosaur that had fallen into a pit of mud.
"This poor animal had been stuck in the mud," James Kirkland, a paleontologist with the Utah Geological Survey and co-author on the new paper, told Utah Public Radio. "You hate to imagine how long it took to actually die, unless it was lucky and some meat-eating dinosaur came and put it out of its misery.”
But what was a very bad day for the young dinosaur about 135 million years ago became a very good day for the paleontologists in 2010, when they first spotted its remains sticking out from the rock. Puzzled by the find, Kirkland brought in experts on European dinosaurs, who tied the Utah specimen to animals that had died out in Spain about 145 million years ago.
The paleontologists think a few European individuals from the new species and other turiasaurs migrated over to America via a land bridge. That migration let turiasaurs carve out a new life for themselves in Utah, which has now become a dinosaur discovery hotspot.
That picture could still change as paleontologists continue to uncover new specimens. One possible alternative explanation is that there are other, older turiasaur remains in the U.S. still waiting to be discovered, which could rewrite the dinosaurs' history. Chances are, there's more immigration paperwork trapped in North America's rock.