Most intriguing have been the mammal tracks.
“The mammal observe form could be very distinctive,” Dr. Lockley mentioned. “Truly they appear a little bit bit like very, very small pads.”
For many of the mammals that lived throughout this period, scientists have not often discovered full skeleton fossils. As a substitute, their data is, as a rule, based mostly on a scattered bone or tooth. Footprints have been discovered earlier than, however often a single impression on a stray piece of rock.
Right here, there are pairs of prints that present the left and proper ft of the mammal in a sitting place. The scientists gave to those prints the identify of Sederipes goddardensis, which “actually means sitting footprint,” Dr. Lockley mentioned.
Dr. Lockley mentioned this was one among solely two recognized websites the place dozens of dinosaur-era mammal footprints had been discovered.
The invention was made by serendipity, and virtually misplaced perpetually.
Ray Stanford, an newbie paleontologist who has turn out to be an skilled on dinosaur tracks, had simply dropped off his spouse, Sheila, who labored at Goddard, after the 2 went for lunch in 2012.
Just a few years earlier on the grounds of Goddard, Mr. Stanford had come throughout a free rock with the footprint of a small three-toed theropod, and the brownish stone was the kind of iron-rich sedimentary materials that usually preserves such prints.
As he was leaving the parking zone, he observed rock of an analogous colour protruding of the grass on a hill about 90 ft away. Mr. Stanford stopped the automotive and went to have a look, and noticed a distinguished dinosaur footprint. “Lo and behold,” he mentioned. “It’s an ideal giant nodosaur. This one was lovely. I used to be in ecstasy as a tracker.”
However there was an issue. Goddard was about to tear up the parking zone and the hill and put a brand new $31 million constructing instead. Officers known as Compton J. Tucker, a Goddard scientist who has participated in geophysical surveys to seek out buried ruins at archaeological websites. Dr. Tucker recalled that as he listened, he thought, “This sounds type of unusual but it surely sounds attention-grabbing.”
Further examination revealed the infant nodosaur’s footsteps and the sauropod print on the different finish of the slab.
Earlier than development on the web site began, Dr. Tucker used ground-penetrating radar to seek for different promising items of sandstone, after which a military of volunteers dug up these areas. However not one of the different items turned out to be as attention-grabbing because the one Mr. Stanford has initially noticed.
Stephen Godfrey, curator of paleontology on the Calvert Marine Museum in Solomons, Md., cleaned the rock and made a fiberglass solid of it. A few years later, the solid ended up in Mr. Stanford’s basement, the place he may take a extra cautious and nearer look.
He noticed the tracks of the 4 small theropods, all headed in the identical route, strolling slowly. “Why have been the theropods strolling slowly?” Mr. Stanford mentioned. “This stuff have been shifting at lower than half a mile per hour.”
He then noticed the steps of the mammals. “This was the actual factor that hit me for a loop,” Mr. Stanford mentioned. “To see them with their potential predators.”
Dr. Lockley got here to Maryland a few 12 months in the past and stayed with Mr. Stanford to see over the slab. After 80 footprints had been mapped, Mr. Stanford thought he was completed. Then his spouse walked up behind him, and identified a pterosaur footprint he had missed. She is a co-author on the paper.
Not one of the footprints on the slab overlap, indicating that the animals all handed in a brief time frame, maybe over a number of hours or days, not going greater than per week or two. The patterns are suggestive of what every animal was doing, however it’s inconceivable to know for sure that the dinosaurs have been searching the mammals.
“That’s undoubtedly a chance,” Dr. Lockley mentioned.
The hill is now gone. If Mr. Stanford had not noticed the slab that in the future, it might have been obliterated by the development. To date, no different such slabs have been discovered. “Finding out dinosaurs isn’t NASA’s main, secondary or tertiary forte,” Dr. Tucker mentioned.
On Wednesday, a duplicate of the slab will likely be unveiled within the atrium of Goddard’s earth science constructing.
NASA often doesn’t seek for indicators of life in its yard, however as an alternative elsewhere within the photo voltaic system and universe. “The actual fact that is discovered proper beneath their nostril,” Mr. Stanford mentioned, “possibly it’s an omen they’re going to start out discovering fossil and extant life on the market.”