Dinosaur Fossilized Footprints Discovered near to Washington DC
When asked to comment on dinosaur discoveries in the United States, most experts may cite discoveries in the Badlands of Montana or the Cleveland-Lloyd Dinosaur quarry in Utah. Certainly, it is true to say that they are many fantastic Mesozoic fossil sites in the west of the USA but despite a little underrepresented in terms of fossil evidence, still still spring a few surprises.
Discovery in Maryland (United States of America)
Now a new study of fossil trackways in Maryland, north-eastern USA has provided a glimpse into a stimulating dinosaur based eco-system. Many of the trackways, have been found just a few miles drive out of Washington DC Trackways and footprints are called trace fossils. Trace fossils preserve evidence of the activity of animals such as their trackways, borings or burrows. The problem with most sets of footprints, even the very best preserved ones, is that, unless the animal is found fossils at the end of the trackway, scientists can never be 100% certain as to the species or genus that actually left the prints. Trace fossils such as footprints do have a significant advantage over other types of fossil such as fossil bones, most are direct in situ evidence of the environment at the time and place the organism was living.
Nine Hundred Fossilized Footprints Found
A total of over 900 fossil footprints from a variety of dinosaurs all dated from the mid Cretaceous have been identified from the area. Theropods, Ankylosaurs (Nodosauridae), Sauropods and Ornithopods are represented by the prints. Palaeontologists have estimated that the trackways were made between 121 and 98 million years ago. Trace fossils of other animals have also been preserved in this part of the USA, one trackway has been identified as a flying reptile, perhaps a Pterosaur flew down to get a drink and its trail was preserved in the soft sediment. Mammal tracks have also been found, indeed one trackway indicates that some mammals were quite large, tracks of a quadrupedal mammal about the size of a large dog have been recorded.
Based on the trace fossil evidence, over two dozen species of dinosaurs were living in Maryland at that time. Scientists who specialize in studying fossil trackways, began to discover tracks in the area while looking out for native Indian artifacts, in the stream-beds that criss cross the area.
They explained that as water and human development erode such beds, "floats" can result. These are pieces of track-bearing substrate that hydrodynamically dislodge from their natural stratigraphic context during stream bank flooding.
All of the discoveries were made either in Prince George's county, near the capital, Washington DC or at the White Marsh Run area of Baltimore county.
Hoping to Put the Fossils on Pubic Display
The pecicular, almost flower-shaped five-toed prints that have been discovered were most probably made by a Nodosaur. Nodosaurs are members of the Ankylosauria, heavily built, slow-moving, plant-eaters with body armour and horns.
Some of the trackways may have been made by young, immature animals. This area may have provided a Cretaceous nursery for many species, a popular nesting and breeding ground for a variety of dinosaurs. The scientists state that they may even have uncovered trackway evidence showing youngsters following adults, a possible insight into animal's behavioral and social relationships.
So far, the team of scientists and researchers responsible for analyzing the huge number of prints have described and published Maryland's first dinosaur track species (called an ichnospecies which translates to 'trace species'). It consist of both front and back footprints of a Hypsilophodontid dinosaur. He named the new dinosaur footprint type or species Hypsiloichnus marylandicus, meaning "trace of a Hypsilophodontid dinosaur from Maryland."
An overview of these, and other, finds was recently published in the journal Ichnos.
Analysis of the region's geology indicates that during dinosaur era, fresh water sources and plant life would have been plentiful. Researchers have excavated fossil pollen from ancient plants, along with fossil wood for a large, now-extinct fern tree similar to today's cycads.
The Smithsonian Museum of Natural History in Washington DC is investigating the possibility of putting some of the tracks on display in a special exhibition. There are certain obstacles to overcome, such as how best to present the casts so that their fine detail can be seen, but such an exhibit be popular with museum visitors. After all, it would give the residents of Washington DC an opportunity to learn about some of the previous residents in the neighborhood.