The work at NASA's Goddard Space Flight Center in Greenbelt, Maryland is usually focused on the future. But a slab of sandstone found on Goddard's ground have given insight into the world of 100 million years ago. Not just a fossil, the Goddard slab shows the rare sight of mammals and dinosaurs interacting.
The story of the Goddard slab begins with a helpful husband with a passion for his hobby. Ray Stanford is an amateur paleontologist, but when he was dropping his wife Shelia off at her job at NASA Goddard one day in 2012, he wasn't looking to find anything. Nonetheless, he noticed an unusual rock outcropping behind his wife's building and decided to do a little investigating. What he found was unmistakable: a 12-inch-wide dinosaur track on exposed rock.
Eventually the slab was excavated, revealing a rock the size of a dining room table, around 8 feet by 3 feet in size. It's imprinted with 70 tracks from eight species, ranging from squirrel-sized mammals to tank-sized dinosaurs like the nodosaur. At the very least, analysis shows, the tracks were made within a few days of each other. It's possible that they might even show predator and prey in the midst of a hunt.
“The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world,” said Martin Lockley, paleontologist with the University of Colorado, Denver, a co-author of Stanford's new paper, in a . “I don't think I've ever seen a slab this size, which is a couple of square meters, where you have over 70 footprints of so many different types. This is the mother lode of Cretaceous mammal tracks.”
What Lockley calls "the Cretaceous equivalent of the Rosetta stone" features 26 different mammals, including the largest ever discovered from the Cretaceous period at around the size of a raccoon's paw. The prints are important because most knowledge of Cretaceous mammals comes solely through finding their teeth. "When you have only teeth, you have no idea what the animals looked like or how they behaved,” Lockley says.
Some of the prints were never discovered before, and especially interesting are a few prints that came in pairs. Pairs signify hind legs, and it "looks as if these squirrel-sized animals paused to sit on their haunches," Lockley says. The prints have been given the name Sederipes goddardensis, which roughly means "sitting traces from Goddard Space Flight Center."
A happy accident, NASA scientists were eager to help out with the discovery made in their backyard. "People ask me, 'Why were all these tracks in Maryland?'" says Compton Tucker, a Goddard Earth scientist who helped with the excavation and has ensured a cast of the slab will be displayed in Goddard's Earth science building.
"I reply that Maryland has always been a desirable place to live.”