Adjunct Research Professor Michael Ryan Names Two New Tribes of Horned Dinosaurs

Wednesday, January 4, 2017

Reconstruction of  a nasutoceratopsin based on CMN 8804 collected in 1937 in  southern Alberta . Art by Andrey Atuchin

Reconstruction of  a nasutoceratopsin based on CMN 8804 collected in 1937
in southern Alberta. Art by Andrey Atuchin

 

Adjunct Research Professor Michael Ryan is the lead author on the latest finding of the Southern Alberta Dinosaur Project. Two new tribes of horned dinosaurs have been described: Nasutoceratopsini and Centrosaurini. This research is based on a fossil skull (CMN 8804) collected almost 80 years ago in southern Alberta, which is now housed locally at the Museum of Nature.

Horned dinosaurs are typically defined by the ornamentation on their heads. Each of the new  tribes followed distinctly different evolutionary paths. Nasutoceratopsini had a long brow horn above each eye and lacked elaborate shield ornamentation. Centrosaurini reversed this pattern, having much shorter brow horns and frills that could include long spikes or hooks. Scientists believe that this ornamentation was important for attracting mates. Without a distinctive frill ornamentation, nasutoceratopsins may have relieved on colorful patterns of the frill to attract mates. Whether this was the case remains unanswered as such patterns  are currently unknown for large-bodied ceratopsians.

The two tribes coexisted across Alberta, Montana and Utah during the Late Cretaceous ~ 76 million years ago. They were not competitors, however, clarifies Dr. Jordan Mallon, another Adjunct Research Professor and co-author of the paper. Their jaw anatomy suggests that they did may have consumed the different types of foods. 

Full Reference: Michael J. Ryan, Robert Holmes, Jordan Mallon, Mark Loewen, and David C. Evans. A basal ceratopsid (Centrosaurinae: Nasutoceratopsini) from the Oldman Formation (Campanian) of Alberta, Canada. Canadian Journal of Earth Sciences. Published online Dec. 13, 2016. http://dx.doi.org/10.1139/cjes-2016-0110

The paper is free to download here: http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2016-0110