A team of scientists from the Smithsonian's National Museum of Natural History, the Carnegie Museum of Natural History and the University of Utah has described an unusual bird-like dinosaur previously unknown to science, resembling a cross between a modern emu and a reptile. The new species, Anzu wyliei, lived 68 to 66 million years ago and was identified from three partial skeletons collected from the Upper Cretaceous Hell Creek Formation in North and South Dakota. The species belongs to Oviraptorosauria, a group of dinosaurs mostly known from fossils found in Central and East Asia. The fossils of Anzu provide, for the first time, a detailed picture of the anatomy, biology and evolutionary relationships of North American oviraptorosaurs. A detailed report about the team's research is published by PLOS ONE March 19.
Hans-Dieter Sues, curator of vertebrate paleontology in the Department of Paleobiology at the National Museum of Natural History, and Tyler Lyson, a postdoctoral fellow at the museum, played significant roles in describing and discovering the fossils and participated in the analysis of A. wyliei, recognizing its status as a new species. Lyson was responsible for the discovery and excavation of one of the three partially complete fossils analyzed by the team; the other two more complete fossils were discovered by private collectors, including Mike Triebold and the Nuss family. All three fossils are now housed at the Carnegie Museum of Natural History in Pittsburgh. Sues and Lyson collaborated with lead author Matthew Lamanna, assistant curator of vertebrate paleontology at the Carnegie Museum of Natural History, and Emma Schachner, a postdoctoral researcher at the University of Utah in Salt Lake City, in describing the new species.
"For almost a hundred years, the presence of oviraptosaurs in North America was only known from a few bits of skeleton, and the details of their appearance and biology remained a mystery," said Sues. "With the discovery of A. wyliei, we finally have the fossil evidence to show what this species looked like and how it is related to other dinosaurs."
Anzu wyliei's Appearance and Biology
The three Anzu specimens preserve almost the entire skeleton of this species, giving scientists their first in-depth look at its striking and unusual anatomy. A. wyliei was roughly 11 feet long and 5 feet tall at the hip. Except for its long tail, it resembled a large flightless bird, with feathers on its arms and tail, a toothless beak and a tall crest on top of its skull. The neck and hind legs were long and slender, similar to those of an ostrich. Unlike in birds, the forelimbs of A. wyliei were tipped with large, sharp claws. The structure of the skull suggests that Anzu may have been an omnivore, and its fossils were found in humid floodplain sediments, like many of the other species excavated from the Hell Creek Formation.
"Over the years, we've noticed that Anzu and some other Hell Creek Formation dinosaurs, such as Triceratops, are often found in mudstone rock that was deposited on ancient floodplains," said Lyson. "Other dinosaurs like duckbills are found in sandstone deposited in or next to rivers."
The fossils of A. wyliei also offer clues about the evolutionary relationships between its family, the Caenagnathidae (pronounced SEE-nuh-NAY-thih-DAY), and the Asian Oviraptoridae. The scientists found that caenagnathids were amazingly diverse, including species that were as small as turkeys and as large as Anzu.
Hell Creek Formation Fossils Highlighted in Upcoming Smithsonian Fossil Exhibition
The National Museum of Natural History will showcase dinosaurs and other fossils from the world in which Anzu lived as part of its upcoming temporary exhibition, "The Last American Dinosaurs: Discovering a Lost World," which opens Nov. 25. The exhibition will feature specimens from the Hell Creek and Lance formations, such as Tyrannosaurus rex and Triceratops. These rock formations date from about 68 to 66 million years ago.
"The Hell Creek Formation has been intensely studied by paleontologists for more than a hundred years, and we're still finding phenomenal specimens," said Kirk Johnson, Sant Director of the National Museum of Natural History. "We are excited and honored to continue sharing our collection of fossil discoveries with our visitors for years to come."
In 2013, the National Museum of Natural History announced a 50-year loan agreement with the U.S. Army Corps of Engineers to transfer a T. rex skeleton to the Smithsonian for eventual display in the museum's new dinosaur hall, scheduled to open in 2019. The skeleton was excavated from the Hell Creek Formation, and it is one of the most complete T. rex specimens ever discovered. The T. rex is set to arrive at the Smithsonian April 15. The last day for the public to visit the current dinosaur hall will be April 27, after which it will close for renovation.
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