The discovery was made by a local dinosaur track expert as he was dropping off his wife, who works at NASA's Goddard Space Center.
A large slab with tracks from over 70 dinosaurs, pterosaurs and mammals was discovered at a NASA's space center parking lot, according to a research paper published this week.
In June 2012, dinosaur track expert Ray Stanford dropped his wife Sheila at her workplace at NASA's Goddard Space Flight Center in Greenbelt, Maryland, when a rock caught his eye. He came closer and discovered a 12-inch-wide nodosaur track.
He then showed his discovery to NASA officials at Goddard, who had until then been too busy to look at the floor. The discovery was then acknowledged by paleontologists, at the amusement of thousands of space scientists who have worked at the NASA campus in Goddard for years.
“Space scientists walk along here, and they’re walking where this big, bungling, heavy-armored dinosaur walked maybe 110, 112 million years ago. It’s just so poetic,” Stanford told the Washington Post back then.
Years later, Stanford decided to come back and take another look, finding more than 70 dinosaur and mammal tracks on the same slab.
The slab was examined by Stanford and paleontologist Martin Lockley, and a paper coauthored by both of them and three other experts was published yesterday in the Scientific Reports journal.
The paper, called “A diverse mammal-dominated, footprint assemblage from wetland deposits in the Lower Cretaceous of Maryland,” describes “one of the highest track densities and diversities ever reported.”
“This is the Cretaceous equivalent of the Rosetta stone,” Lockley said.
The slab is dominated by small mammal tracks and includes the new ichnotxon, a name used by experts to name and identify fossil tracks, Sederipes goddardensis in a sitting posture.
The tracks belong to the Cretaceous period, the last of the Mesozoic era, in which a larger number of mammals, birds and even flowering plants started to appear, hence the 26 mammal tracks in the slab.
According to the paper, mammal fossils from the Cretaceous period are scarce and mostly jaws and teeth remains are found, so this slab represents a one of a kind research opportunity.
The paper identifies Pterosaur, Nodosaur, Sauropod and Theropod tracks, but fails to identify any mammal, as tracks from Mesozoic mammals are scarce and there's currently little possibility for identification.
“As mammal tracks, representing eutherians and/or metatherians, are rare in the Mesozoic, there is little precedent for identifying them or assigning taxonomic labels,” reads the paper.
The Cretaceous period's end is marked with the impact of a large meteorite with the Earth, which led to the extension of three quarters of the living species, including most of the dinosaurs and plants.