- The discovery of a dinosaur footprint at NASA Goddard Space Flight Center in 2012 led to the discovery of one of the richest sets of prehistoric tracks from the Cretaceous Period ever seen.
- Among the footprints is "the mother lode of Cretaceous mammal tracks," according to one of the authors of a new study examining the site.
- The discovery shows how early prehistoric mammals interacted with dinosaurs and flying reptiles like pterosaurs more than 100 million years ago.
The scientific treasures at NASA Goddard Space Flight Center in Maryland stretch back far before the space age, as a recent discovery illustrates.
It turns out they go at least back to the Cretaceous Period, when small mammals scurried about, intermingling with dinosaurs and hiding from hunting pterosaurs that swooped down from the skies.
That's part of the story told by a remarkable slab of sandstone discovered in 2012. The rock contains more than 70 tracks from dinosaurs and mammals, which are described in a new paper published in the journal Scientific Reports on Wednesday.
The wealth of information contained in the slab is enough to transform what we know about how early mammals interacted with dinosaurs and other prehistoric creatures.
"The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world," Martin Lockley, a paleontologist with the University of Colorado, Denver and a co-author on the new paper, said in a feature on the NASA Goddard website. "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."
An astounding discovery
The site was first uncovered on June 25, 2012, by Ray Stanford, a local dinosaur track expert whose wife Sheila works at Goddard. As the Washington Post's story about the original discovery tells it, Stanford was struck a hunch: He decided to return to a site on the campus where years before he'd found a rock with the imprint of a track from a theropod, a carnivorous dinosaur in the same family as the velociraptor.
There was a lot there waiting to be found.
The discoveries started with a print from a nodosaur, a large plant-eating dinosaur covered in spiky armor.
"Think of it as a four-footed tank," Stanford said at the time.
But that wasn't all. As the new study describes, there were more nodosaur tracks waiting to be found, along with tracks from sauropods, massive lumbering giants with long necks and long tails. There were also tracks from small theropods — three-toed predators from the family of Tyrannosaurus and the Velociraptor — though these ones were the size of crows'. Pterosaur tracks showed that flying reptiles hunted in the area, too.
In addition to all of those, scientists also found many mammal tracks, some likely from species that had never been studied.
These creatures were mostly about the size of squirrels and were probably being hunted by the theropods and pterosaurs. At least one set of tracks is the largest set of mammal footprints — about the size of tracks from a modern raccoon — ever found from the Cretaceous period.
"This could be the key to understanding some of the smaller finds from the area, so it brings everything together," Lockley told the NASA team. "This is the Cretaceous equivalent of the Rosetta stone."
There's something poetic about this astounding discovery being found at a place scientists analyze both the future and, by studying the stars, the past.
As Jim Garvin, the chief scientist at NASA Goddard put it in 2013, we're just now seeing the light that was emitted by stars back when these prehistoric creatures walked the Earth.
"One of the amazing aspects of this find is that some of the starlight now seen in the night sky by astronomers was created in far-distant galaxies when these dinosaurs were walking on mud flats in Cretaceous Maryland where Goddard is now located," Garvin said in 2013. "That starlight (from within the Virgo Supercluster) is only now reaching Earth after having traveled through deep space for 100 million years."
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