Anzu wyliei

Anzu

Anzu (named for Anzû, a bird-like daemon in Ancient Mesopotamian religion) is a genus of caenagnathid dinosaur from North Dakota, South Dakota, and Montana. This dinosaur lived during the Late Cretaceous (upper Maastrichtian stage, about 67.2 to 66.0 million years ago) in what is now the Hell Creek Formation. The main species, Anzu wyliei, is known from many skeletons that show both its skull and body parts. It was named in 2014 by scientists Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner, and Tyler R. Lyson.

Anzu was chosen as one of the "Top 10 New Species" discovered in 2014, showing how important this find was for science. In 2015, it was again recognized by the International Institute for Species Exploration as a very important discovery. Another unnamed species of this dinosaur was also found in Montana in the Hell Creek Formation, in Carter County. This dinosaur helps scientists learn more about life from that time long ago.

History of discovery

In 1998, a person named Fred Nuss found the first two partial skeletons of Anzu on a ranch in South Dakota. These skeletons were mostly scattered. Another skeleton was found later by Scott Haire at his uncle’s ranch in Marmarth, North Dakota. These fossils give us a good picture of Anzu wyliei, showing about 75 to 80 percent of its whole body.

Researchers from several museums studied these fossils and realized they belonged to the same species. They worked together to learn more about Anzu. This dinosaur is special because it is one of the best-preserved examples of a North American oviraptorosaur. It had big crests on its skull, a beak instead of teeth, and a skeleton that looked very much like a bird. The name Anzu wyliei honors a person named Wylie J. Tuttle, whose grandparent helped support the museum where the fossils are kept.

Description

Anzu wyliei had a toothless beak, a crest on its head, long arms with big claws, strong legs, and a short tail. This dinosaur was about 3.5–3.75 metres (11.5–12.3 ft) long and stood up to 1.5 metres (4.9 ft) tall. It was a large oviraptorosaur from North America.

Scientists found special traits that make Anzu unique. It had a high, crescent-shaped crest on its skull, a wider occipital condyle compared to its foramen magnum, and a special shape on the front of its lower jaw. The lower jaw had a long projection at the back. It also had a divided lower end of the radius bone and a small bump on the front of the ankle bone.

Classification

Anzu was part of a group of dinosaurs called oviraptorosaurs, in the family Caenagnathidae. Scientists studied its family tree and found it might be related to another dinosaur called Caenagnathus.

Before discovering Anzu wyliei, experts thought oviraptorosaurs in North America would look like those in Asia, since the two areas were once connected by land. But this find shows that North American oviraptorosaurs were more closely related to each other than to those in Asia.

Paleobiology

Anzu was probably an omnivore or herbivore, but its beak wasn’t very strong. It had thicker legs and different lower jaws compared to smaller dinosaurs from Asia.

The fossils of Anzu wyliei were found in mudstone, a type of rock from old floodplains. This suggests that Anzu lived in a very different place from its Asian relatives, who lived in dry or semi-dry areas. Experts think Anzu was a fast-moving dinosaur that could eat many types of food, like plants, small animals, and maybe even eggs.

Though Anzu had some features similar to modern birds, it was not a bird dinosaur and went extinct 66 million years ago along with many other dinosaurs. Its bird-like traits are an example of convergent evolution, meaning it evolved similar features independently. Scientists believe it likely showed many bird-like behaviors.

The large crest on Anzu’s head had an unclear purpose, but it was very big and made of thin bone, so it likely wasn’t used for fighting. It might have been used to show off to others of its kind, much like some birds today. Fossils show signs of injuries, such as a healed broken rib, but it isn’t known what caused these injuries.