Creature Feature 16

Greetings, fans! It's hard to believe that we've already done 15 Creature Features!

This week we'll be looking at the recently discovered Oviraptorosaurian Anzu wyliei!

Anzu wyliei model, WIP. Feathers will be added.

Anzu wyliei is easily distinguishable amidst the dinosaurs of Hell Creek by it's toothless beak, large crest, long arms with relatively straight claws (as opposed to the more curved claws found in dromaeosaurs), and rather short tail. It was the largest known Oviraptorosaur from North America , at approximately 3-3.5 meters in length, 1.5 meters tall at the hips, and weighing in at an estimated 200-300kg (Lamanna et al., 2014).

Cladistic analyses place Anzu wyliei in the family Caenagnathidae, as sister to Caenagnathus collinsi (Lamanna et al., 2014). It is possible that in the future this species will be reassigned to Caenagnathus (the revised name would be Caenagnathus wyliei), though since both genera remain monophyletic in current phylogenies such revision is not necessary [at least in my opinion]. The relationships revealed by the phylogeny demonstrated that North American Oviraptorosaurs were more closely related to each other than they were to their Asian relatives (Jemison, 2014).

The diet of A. wyliei is still not certain - it may have been an omnivore or an herbivore, though its beak is less robust than those in the Asian family Oviraptoridae (Lamanna et al., 2014). Other differences from the Asian Oviraptoridae include thinner legs and a different mandibular structure (Fawcett, 2014). Additionally, it lived in a much less arid environment - the remains were found in mudstone attributed to a floodplain environment (typical of Hell Creek) (Jemison, 2014). In the original description, the authors hypothesize that it was likely able to consume a wide variety of foods, ranging from vegetation to small animals, and even eggs (Lamanna et al., 2014).

Another mystery is the function of the large crest on the head. While all oviraptorosaurs have a crest, the crest of Anzu is exceptionally large. The crest was made of extremely thin bone, and as such would not have been able to handle stress without risk of severe damage. Given the similarities in shape to the crest of the modern Cassowary, some believe it may have served a similar purpose, serving as a display to attract mates.

Another interesting note is that some remains show evidence of injuries. These include a healed broken rib and an avulsion fracture on one of the toes (possibly proximal phalanx IV). Currently, it is unknown whether these injuries were the result of intraspecific combat or are due to interactions with predators (though those are not the only two possible causes, of course) (Lamanna et al., 2014).

I hope you have learned a bit more about the rather interesting Anzu wyliei! Since it was only described 2 years ago, there has not been enough time for lots of research to be published, so that is why my sources are rather repetitive. Hopefully, as time goes by more people will be working on this amazing creature!

Acknowledgements:
Lamanna, M. C.; Sues, H. D.; Schachner, E. R.; Lyson, T. R. 2014. A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America. PLoS ONE 9 (3): e92022.
Jemison, Micaela. 2014. One Scary Chicken - New Species of Large, Feathered Dinosaur Discovered. insider.si.edu. Retrieved April 19, 2016.
Fawcett, Kirstin. March 19, 2014. Scientists Discover a Large and Feathered Dinosaur that Once Roamed North America. Smithsonianmag.com. Retrieved April 19, 2016.