NASA has discovered one of the best preserved fossilised tracks of dinosaurs, pterosaurs and ancient mammals in its Goddard Space Flight Center in Greenbelt, Maryland. The facility is responsible for handling a variety of NASA missions, including the Hubble Space Telescope, OSIRIS-REx and MAVEN. The slab of rock, about two and a half meters long and one meter wide, has almost 70 well preserved tracks from eight species. Impressions by nodosaurs, sauropods, theropods and pterosaurs share space with 26 mammalian tracks on the slab. Martin Lockley, a palaeontologist, with the University of Colorado, Denver says “This is the mother lode of Cretaceous mammal tracks.” The imprints of all the tracks are believed to have been left behind by the animals between 110 to 112 million years ago, within the span of a few days. The location is believed to have been at the fringes of a wetland. This was soon after the earliest mammals appeared on Earth.
The nodosaurs are related to the ankylosaurs, and were tank sized dinosaurs with armoured plates along their backs and spines on their entire bodies. One of the most well preserved ever was discovered last year, and belongs to a nodosaur. There are two sets of nodosaur prints in the slab, one believed to belong to an adult, and the other to a juvenile. The juvenile could be have been following in the footsteps of the adult. The sauropod was a long plant eating dinosaur, similar to a brachiosaurus or a brontosaurus. Most of the theropod footprints belonged to a small crow sized animal, which is from the same family as the Velociraptor. There were also larger theropod footprints, possibly of one capable of flight. There are also tracks of what is suspected to be an early crocodile. There were pterosaur tracks as well, which were from flying reptiles similar to pterodactyls. The pterosaurs are distinct from the dinosaurs, and more information about all these ancient reptiles is available in the February issue of Dmystify, which is on stands right now. Most of the mammalian tracks belong to small squirrel sized animals. One of the tracks is from a raccoon sized animal, making it the largest known mammalian footprint from that time period.
The slab was originally discovered in 2012. Ray Stanford, a local dinosaur tracking was at the NASA facility to drop off his wife, Sheila who worked there. On his way back, he stopped to check out an interesting rock, which happened to have a 12 inch wide nodosaur print. Follow on observations, after cleaning out the site, revealed additional footprints. Researchers investigated nearby areas, and found no other footprints close to the slab. A silicon rubber cast was taken of the slab, before it was removed for further analysis. In 2013, Jim Garvin, Chief Scientist at NASA Goddard had said, “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. That starlight (from within the Virgo Supercluster) is only now reaching Earth after having travelled through deep space for 100 million years.”
The tracks capture a food pyramid of sorts. At the bottom of the food chain were worms or larva of many species, which were food for the smaller mammals. Many of the mammalian tracks appear in pairs, which indicated that they were sitting on their haunches. The creatures have been named Sederipes goddardensis after the space centre. These smaller mammals were preyed on by the by the carnivorous dinosaurs. Four crow-sized theropods made parallel tracks, suggesting that they were hunting in a group. The pterosaurs could have been feeding on both the mammals as well as the small carnivorous dinosaurs. The slab includes traces of a pterosaur feeding. The nodosaur prints could have been made when the animal was running away from a large predator, which is not represented in the fossil finding.
The investigation into the slab has been documented in research published in Scientific Reports. Researchers are continuing their investigations into the slab. The wide variety of prints can allow researchers to understand other finds in the vicinity. Lockley describes to the fossil as “the Cretaceous equivalent of the Rosetta stone.”