Propanoplosaurus—Making Maryland Proud, 2012
Long ago in a flooding plain of the prehistoric Cretaceous Period, at least one 13 centimeter long tiny baby nodosaurid dinosaur was overcome by water or possibly by other fleeing creatures in the wake of a flood. Ultimately, the little dinosaur drowned and was covered by sediment to be unveiled 112 million years later in what is today the eastern United States—specifically Maryland.
To date, this is the youngest nodosaur ever found, and may be seen on display at the Smithsonian National Museum of Natural History in Also, this nodosaur is the first hatchling of any dinosaur to be recovered in the eastern US. The specimen was identified by noting the skull’s distinctive pattern of bumps and grooves, which were revealed immediately upon cleaning the fossil. The little prehistoric creature had become immobilized on its back frozen in time as much of its body was imprinted into the sediment before fossilization finally took place.
Due to the lack of fossilized egg shells found after close inspection of the area, scientists believe that this particular nodosaurus—along with any others in the area at the time—was in fact already hatched and mobile.
A computer analysis was performed, measuring the proportions of various recorded ankylosaur (group containing nodosaurid dinosaurs). These comparative measurements enabled scientists to mark the specimen as nodosaurid Propanoplosaurus marylandicus. Had this specimen survived to grow into its adult form, it would likely have reached 20—30 feet long.
Propanoplosaurus Surprises Maryland, 2011
When prehistoric dinosaur tracks were recently discovered at NASA’s Goddard Space Flight Center in Maryland, area scientists and residents were gleeful in their recognition of the fact that dinosaurs did, in fact, roam their own bit of the earth millions of years ago.
Those tracks also belong to Propanoplosaurus marylandicus. Propanoplosaurus was a Cretaceous Period nodosaurid dinosaur, of the family Nodosauridae which is itself a type of ankylosaurian dinosaur. The genus Propanoplosaurus was named and described by Stanford, David Weishampel and Valerie DeLeon in 2011, and refers to the location of discovery in Maryland.
Ankylosaurian dinosaurs span the range from the prehistoric Late Jurassic Period to the Late Cretaceous. During the period of 75—65 million years ago, some ankylosaur genera developed thick and elaborate armor as a natural defense against predatory aggression by the likes of Tyrannosaurus rex.
Nodosauridae (knobbed lizards) are a family of herbivorous ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe. Like Propanoplosaurus, other nodosaurid fossils have been discovered in eastern US regions such as Baltimore and Washington. Nodosaurid dinosaurs are described as medium—large and heavily built quadrupedal herbivores. Their teeth are small and denticulate, and nodosauridae have parasagittal rows of osteoderms (armors) on the dorsolateral surfaces of their bodies.
“The family Nodosauridae was erected by Othniel Charles Marsh in 1890, and anchored on the genus Nodosaurus”
Other nodosaurae Propanoplosaurs genus type is Nodosaurus textilis. The first armored dinosaurs to be discovered in North America, this type genus was first known for its body armors, described as bony dermal plates which covered the top of its body. It is believed that Nodosaurus textilis had spikes along its side as well. Its legs and neck were short, and this type species had five toes, where other Nodosaurae are known for four.
Propanoplosaurus Defense
It is worth noting that nodosaurus were the first ankylosaurs to exist with not just clubs on their tails. It is believed that their defense method would have resembled that of today’s hedgehog, which when threatened will drop to the ground and roll up so that only it’s armored back and sides are exposed.
Another nodosaur footprint—thought to be a baby Propanoplosaurus—was found in the immediate area of the first, adult print found in Maryland.
