A team of paleontologists from Oklahoma State University, the University of Toronto and Royal Ontario Museum has added another species of caenagnathid oviraptorosaurian dinosaur to the prehistoric catalog: Eoneophron infernalis.
Eoneophron infernalis lived in what is now the United States during the Late Cretaceous epoch, between 68 and 66 million years ago.
The fossilized remains of the species were collected from exposures of the Hell Creek Formation in South Dakota.
These sediments resemble those of typical floodplain deposits such as siltstones with organic material as seen elsewhere in the Hell Creek Formation.
“When we first examined the bones, we identified them as belonging to a family of dinosaurs known as Caenagnathidae, a group of birdlike dinosaurs that had toothless beaks, long legs and short tails,” said Oklahoma State University paleontologist Kyle Atkins-Weltman and colleagues.
“Direct fossil and inferred evidence indicates these dinosaurs were covered in complex feathers, much like modern birds.”
“The only known species of caenagnathid from this time and region was Anzu. Covered in feathers and sporting wings and a toothless beak, Anzu was between 200 and 340 kg.”
“Despite its fearsome nickname, though, its diet is a matter of debate. It was likely an omnivore, eating both plant material and small animals.”
“Because our specimen was significantly smaller than Anzu, we simply assumed it was a juvenile.”
“We chalked up the anatomical differences we noticed to its juvenile status and smaller size — and figured the animal would have changed had it continued to grow.”
“Anzu specimens are rare, and no definite juveniles have been published in the scientific literature, so we were excited to potentially learn more about how it grew and changed throughout its lifetime by looking inside its bones,” the researchers said.
“Just like with a tree’s rings, bone records rings called lines of arrested growth. Each annual…
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