A slab of sandstone discovered a few years ago provided rare evidence of interactions between dinosaurs and mammals, through the ancient footprints embedded on its surface.
The slab, which offered a glimpse into how the world looked millions of years ago, was ironically found at NASA's Goddard Space Flight Center in Greenbelt, Maryland, where scientists look to the stars and toward the future.
Sandstone Slab With Dinosaur And Mammal Tracks
A new paper published in the Scientific Reports journal discussed the slab of sandstone discovered by dinosaur track expert Ray Stanford in 2012. The slab is described to have "one of the highest track densities and diversities ever reported."
Stanford's discovery, however, was simply a stroke of luck. Stanford dropped off his wife, Sheila, at Goddard, where she worked. Afterward, a rock outcropping on a hillside right behind Sheila's building caught his eye. Stanford parked his vehicle and investigated the slab of sandstone, and he immediately saw a 12-inch-wide footprint of a dinosaur on the exposed portion of the rock.
The slab of sandstone was excavated, revealing that it was as big as a dining room table at about 8 feet long and 3 feet wide. The first footprint that Stanford discovered, however, was far from being the only one on it.
Further examination revealed that the rock had about 70 tracks from eight different species. Analysis suggested that the footprints were made just a few days apart in a period about 100 million years ago, at a location that may have been at the edge of wetlands.
"The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world," said University of Colorado paleontologist Martin Lockley. "This is the mother lode of Cretaceous mammal tracks."
Analyzing The Dinosaur And Mammal Footprints
The slab of sandstone featured tracks from long-necked sauropods, armored nodosaurs, Tyrannosaurus Rex relative theropods, and even flying pterosaurs that apparently landed on the surface.
However, most intriguing were the presence of mammal tracks, including a pair of footprints that apparently came from a mammal that was in a sitting position. At least 26 mammal tracks have been spotted on the sandstone slab, showing that there were many mammals in the area, possibly eating worms and grubs. The small dinosaurs, meanwhile, may be hunting the mammals, while the pterosaurs were hunting both the small dinosaurs and the mammals.
According to Lockley, the sandstone slab was just one of two known sites in the world where a significant collection of mammal footprints during the dinosaur era were discovered.
