This oviraptorosaur belongs to a little-known family of dinosaurs, some members of which lived shortly before the crisis at the end of the Cretaceous period that caused the extinction of the dinosaurs.
Oviraptorosaurs, whose name means “egg-stealing lizard,” were feathered dinosaurs that lived in Asia and North America during the Late Cretaceous Period, 100 to 66 million years ago. Within this group, the caenagnathids bring together a dozen species, some of which are not precisely defined as they can be identified from partial fossils. In North America, the largest caenagnathid known on this continent was found in the Hell Creek Formation in 2014: Anzu Wyliei, also called “the chicken from hell” because of its alleged similarity to the Gallinaceae. With a length of 3.5 meters, a weight of 200 to 300 kilos and a height of 1.5 meters, it was indeed something to be afraid of!
A smaller species
In the same Hell Creek Formation, several smaller remains were recovered by Kyle L. Atkins-Weltman, a paleontologist at Oklahoma State University. The bones shared similarities with those of Anzu Wyliei, leading specialists to wonder whether they were in the presence of a juvenile. A hypothesis refuted in an article published in the journal Plos One, which led to the identification of a new species of caenagnathid: Eoneophron infernalis, which lived just over 66 million years ago.
“Although it is the size that sets these two dinosaurs apart, at first glance, when you look closely at the bones, you can see many other differences. For example, the head of the femur does not form the same angle with the diaphysis, the proximal “The knuckle bone is fused in Eoneophron, while it is absent in Anzu and most other caenagnathids,” explains Kyle Atkins.
Because the skeleton is incomplete, it is difficult to determine the size of Eoneophron infernalis. The authors assume that, with a length of less than two meters and a weight of around 80 kilos, it was significantly smaller than Anzu Wyliei.[…]
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