At least 70 ancient footprints belonging to different species of dinosaurs and mammals from the Cretaceous Period were discovered in NASA’s backyard, etched on a large piece of sandstone about the size of a dining room table.
The slab of sandstone, eight-foot long and three-foot wide, was dug up at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and is believed to bear the marks of interactions between dinosaurs and mammals more than 100 million years ago.
This remarkable find is credited to Ray Stanford, a dinosaur track expert, who came across the Cretaceous fossils back in 2012, while out on a routine drive. According to a NASA news release, Stanford made the fortuitous discovery after dropping off his wife at work in one of the Goddard buildings.
Stanford initially spotted the 12-inch-wide track left behind by an adult nodosaur, an armored plant-eating dinosaur that Stanford describes as “a four-footed tank.” From there on out, things evolved from excitement to bewilderment, as more and more ancient tracks emerged from the same chunk of sandstone in the following years.
Soon after Stanford’s initial discovery, the sandstone was excavated by Stephen J. Godfrey, curator of paleontology at the Calvert Marine Museum in Solomons, Maryland. Godfrey’s team made a mold and cast of the eight-foot long fossil, which has been intensely studied since 2012, only to yield more and more surprises.
A thorough analysis of the sandstone slab over the years revealed “it was covered in preserved tracks” left behind by eight different species of prehistoric creatures all the way back from the Cretaceous. These animals range in size from mammals no bigger than a squirrel to “tank-sized dinosaurs,” notes the news release.
In total, the researchers have counted more than 70 animal tracks imprinted in the sandstone at Goddard — one of the two biggest collections of ancient footprints ever recovered from a single site.
Among the dinosaur species that left their mark on the 100-million-year-old slab of sandstone, NASA mentions a juvenile sauropod (the gentle plant-eating giants of the Cretaceous plains, easily recognizable by their long necks), as well as several pterosaurs (flying reptiles that that were, in fact, airborne cousins of dinosaurs).
Another interesting discovery was the tracks left behind by small theropods, “crow-sized carnivorous dinosaurs closely related to the Velociraptor and Tyrannosaurus rex,” disclosed the news release. According to TeCake, four such dinosaur footprints were recovered from the site.
Additionally, in a surprising turn of events, the researchers also uncovered the footprints of a baby nodosaur right next to the famous adult nodosaur track that set everything in motion back in 2012. These second tracks were discovered “beside and within the adult print,” which suggests the two animals may have been traveling together.
Yet the real treasure trove lies in the collection of at least 26 mammal prints found together with the dinosaur tracks — “one of the highest track densities and diversities ever reported,” according to a study documenting the find, published yesterday (January 31) in the journal Scientific Reports.
Study co-author Martin Lockley, paleontologist at the University of Colorado, Denver, described this significant find as “the mother lode of Cretaceous mammal tracks.”
“The concentration of mammal tracks on this site is orders of magnitude higher than any other site in the world,” Lockley said in the news release.
“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.”
Perhaps the most notable mammalian tracks discovered at the Goddard site are the Sederipes goddardensis, named after the space flight center. These prints were made by the hind feet of squirrel-sized mammals and represent “an unusual configuration” of fossilized tracks that indicate the animals were sitting down.
The Goddard fossil also yielded the largest mammal track ever discovered from the Cretaceous. The footprint measures about four inches square and is roughly the size of a raccoon’s print.
The diversity of animal tracks seems to suggest the area was once a feeding zone for both mammals and dinosaurs, Science Examiner reports. An analysis of the sandstone revealed the site may have once been the edge of a wetland, where ancient creatures came in search for food.
The mammals that left their tracks on the slab of sandstone may have been both hunters and prey at the same time, shows International Business Times, noting that the small mammals could have been looking for worms under the watchful eye of the theropods.
At the same time, the pterosaurs might have been on the hunt for both the mammals and the small dinosaurs, reveals the NASA news release, painting a vivid picture of what Maryland may have looked like 100 million years ago.
In Lockley’s opinion, the impressive assemblage of dinosaur and mammal tracks — which he has dubbed “the Cretaceous equivalent of the Rosetta stone” — may have been made on the same day, in the span of a few hours, CBS News reports.
Compton Tucker, a Goddard Earth scientist involved in the excavation, supports this theory, explaining that none of the tracks are overlapping — as would be the case with multiple prints made over a longer period of time.
“It’s a time machine,” Stanford points out, remarking the Goddard fossil captures the interaction between dinosaurs and mammals during the Cretaceous.
“We see the interaction of how they pass in relation to each other. This enables us to look deeply into ancient times on Earth. It’s just tremendously exciting.”