Researchers have found a cache of 100 million-year-old dinosaur tracks and different fossils embedded within the foothills of an Alaskan mountain vary. The fossil web site, within the Nanushuk Formation beneath the De Lengthy Mountains, gives a window right into a thriving Cretaceous ecosystem populated with dinosaurs of all sizes, in keeping with a College of Alaska Fairbanks assertion launched March 8. Paleontologists examined the positioning between 2015 and 2017. They discovered 75 dinosaur tracks left by meat and plant-eating dinosaurs, although they did not determine particular species. “This place was simply loopy wealthy with dinosaur footprints,” lead writer Anthony Fiorillo, government director of the New Mexico Museum of Pure Historical past and Science, stated within the assertion.Associated: ‘Reduce down of their prime’: Dinosaurs had been thriving in Africa earlier than the asteroid hitFiorillo and his colleagues found the positioning was a preserved historic panorama, with fossils of 2-foot-wide (60 centimeters) tree stumps, leaves, tracks and feces.”It was identical to we had been strolling by way of the woods of hundreds of thousands of years in the past,” he stated.Get the world’s most fascinating discoveries delivered straight to your inbox.The researchers offered their findings in a examine printed Jan. 30 within the journal Geosciences.A theropod monitor (left) and a fossilized tree trunk (proper) found on the Nanushuk Formation in Alaska. (Picture credit score: Anthony Fiorillo (left) and Paul McCarthy (proper))The Nanushuk Formation is round 94 million to 113 million years outdated and dates to the Albian-Cenomanian Age of the Cretaceous interval (145 million to 66 million years in the past), in keeping with the assertion. A majority of the tracks (59%) had been left by two-legged herbivorous dinosaurs, collectively referred to as bipedal ornithischians. This group contains animals akin to helmet-headed pachycephalosaurs, which weren’t recognized within the examine. 4-legged plant eaters, or quadrupedal ornithischians, made up 17% of the tracks. A few of these belonged to ceratopsians, a bunch that features the three-horned Triceratops. The ecosystem additionally hosted meat-eating dinosaurs, with 9% of the tracks left by largely carnivorous, nonavian theropods. The authors famous that a few of these tracks had been throughout the dimension vary of Turonian theropods akin to Suskityrannus, a 3-foot-tall (1 meter) tyrannosaur nicknamed “mini rex,” and Timurlengia, which was in regards to the dimension of a horse. Shorebirds left the ultimate 15% of found tracks. Nearly half of North America’s dwelling shorebirds breed within the Arctic in the course of the area’s heat months, and the authors famous that the excessive frequency of extinct shorebird tracks right here instructed the identical factor occurred within the Cretaceous. The crew additionally used the formation to study extra in regards to the historic Arctic’s heat and moist local weather. By calculating the imply annual precipitation from wooden fragments, they discovered that the Arctic dinosaurs lived in a local weather much like that of modern-day South Florida. “The temperature was a lot hotter than it’s at present, and what’s probably extra attention-grabbing is that it rained loads,” Fiorillo stated. “The samples we analyzed point out it was roughly equal to modern-day Miami. That is fairly substantial.”