A slab of rock bearing the impression of a hatchling armored… (Courtesy of Ray Stanford,…)
Some 110 million years after its birth, a Maryland-born dinosaur has finally been given a name.
The infant armored dinosaur, smaller than a dollar bill, apparently drowned in a flood plain not long after it hatched during the Early Cretaceous Period. Its remains were buried in sediment, fossilized and preserved in rock until 1997.
That's when amateur fossil hunter Ray Stanford of College Park found the rock in a Prince George's County streambed, inside the Washington Beltway.
Last week, Stanford and Johns Hopkins University scientist David Weishampel described the fossil in an article published the Journal of Paleontology. And they gave the little dinosaur a name: Propanoplosaurus marylandicus.
Weishampel, professor of anatomy at the Hopkins School of Medicine, called the animal the youngest "nodosaur," or armored dinosaur ever discovered, and the first hatchling of any species ever found in the eastern United States.
"Now we can learn about the development of limbs and the development of skulls early in a dinosaur's life," Weishampel said. "The very small size also reveals that there was a nearby nesting area, or rookery, since it couldn't have wandered far from where it was hatched." Small nodosaur footprints were found nearby.
Stanford has collected a small mountain of dinosaur track fossils in Washington-area streambeds in the last 15 years.
When Weishampel saw his fossil and asked him to join in describing it in a scientific paper, he said, "Of course, I was both thrilled and honored."
Careful study by Weishampel and his colleagues concluded that the little dinosaur drowned. It settled on its back in the mud, leaving a clear fossil impression of its back and the top of its skull. Its size, porosity of its bones and development at the bone ends were evidence of its young age, they concluded. Had it lived, it would have grown to be 20 to 30 feet long.
They identified the creature as a nodosaur by identifying a distinctive pattern of bumps and grooves on its skull. They used a computer analysis of the skull to compare it with other species like it.
"The result," Stanford said, "was that we have a nodosaur distinctly different from any ever found, and in the paper we have described it as a new genus (Propanplosaurus), and honored the state in which I found it, via the species name (marylandicus)."
The fossil is on display in the "Dinosaurs in our Backyard" exhibit, at the Smithsonian Institution's National Museum of Natural History.
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