66-Million-Year-Old Fossil Reveals New Dinosaur Roaming in the US Before Mass Extinction
Paleontologists have identified a previously unknown dinosaur species that roamed in the United States before the mass extinction. The fossils were unearthed in Meade County, South Dakota.
New Dinosaur Species Identified
In a new study, researchers described the new dinosaur species they discovered in the United States. According to Kyle Atkins-Weltman, one of the authors of the study with Oklahoma State University, the creature likely stood about 3 feet tall at the hip. It may have weighed roughly 130 and 216 pounds --similar to a human.
The species belongs to a class of dinosaurs called Oviraptorosaurs, which included highly bird-like creatures that lived in North America and Asia between 145 and 66 million years ago during the Cretaceous period. Later members had toothless beaks, and they had long legs, short tails, and intricate feathers.
The new species, called Eoneophron infernalis, existed between 68 and 66.5 million years ago at the end of the Cretaceous period. In general, this moniker means "Pharaoh's dawn chicken from hell."
The first word in the name refers to the dinosaur's genus (or group of species) and is derived from the ancient Greek term eo, which means "dawn." The second word in the new species name is derived from the Latin word for hell, which refers to the location of the fossils used to describe the new dinosaur. Neophron is the genus name of the Egyptian vulture, sometimes known as the "pharaoh's chicken."
These fossils were discovered in South Dakota and show a portion of the hindlimb. The region is a section of the geological formation known as Hell Creek, which spans parts of North Dakota, South Dakota, Wyoming, and Montana.
"The Hell Creek formation is significant because it preserves the very last dinosaurs to ever roam western North America," Atkins-Weltman added. "There are not a great deal of dinosaur-bearing formations outside that region that also include the impact layer, so formations like the Hell Creek give us an opportunity to glimpse the very end of the age of dinosaurs."
More About Eoneophron Infernalis
E. infernalis is mainly distinguishable from its larger, better-known cousin Anzu wyliei (also known as the "chicken from hell") based on some characteristics in their ankle that are not visible when they are alive. The first description of Anzu, also based on fossils found in the Hell Creek Formation, was released in 2014.
E.infernalis would have resembled Anzu physically as both reportedly had a short tail, long arms with gripping hands and feathered wings, and a toothless beak. Like Anzu, it would have had a bony crest on its head, though the precise shape would have been different.
Anzu and the newly discovered species are members of the caenagnathid family, a subgroup of Oviraptorosaurs. Because of their scarcity and frequent fragmentation, these dinosaurs, especially those from North America, are not very well known.
"I'd say, based on what we have, these animals were opportunistic omnivores, with some species tending more towards carnivore, specifically eating small animals that could swallow whole while others may have been more herbivorous. Since these animals didn't have teeth, it's much harder to assess their diet," per Atkins-Weltman.
The finding of the new species is noteworthy because some scientists argue that the asteroid impact was only the final blow in a protracted extinction process, with dinosaur diversity declining towards the end of the Cretaceous period.
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