Palaeontologists initially thought that the bones of Albertavenator belonged to its close relative Troodon, which lived around 76 million years ago — five million years before Albertavenator. Both dinosaurs walked on two legs, were covered in feathers, and were about the size of a person. New comparisons of bones forming the top of the head reveal that Albertavenator had a distinctively shorter and more robust skull than Troodon, its famously brainy relative.

This is a life recreation of Albertavenator curriei. Credit: Illustrated by Oliver Demuth. © Oliver Demuth

“The delicate bones of these small feathered dinosaurs are very rare. We were lucky to have a critical piece of the skull that allowed us to distinguish Albertaventaor as a new species.” said Dr. David Evans, Temerty Chair and Senior Curator of Vertebrate Palaeontology at the Royal Ontario Museum, and leader of the project. “We hope to find a more complete skeleton of Albertavenator in the future, as this would tell us so much more about this fascinating animal.”

Identifying new species from fragmentary fossils is a challenge. Complicating matters of this new find are the hundreds of isolated teeth that have been found in Alberta and previously attributed to Troodon. Teeth from a jaw that likely pertains to Albertavenator appears very similar to the teeth of Troodon, making them unusable for distinguishing between the two species.

“This discovery really highlights the importance of finding and examining skeletal material from these rare dinosaurs,” concluded Derek Larson, co-author on the study and Assistant Curator of the Philip J. Currie Dinosaur Museum.”

The identification of a new species of troodontid in the Late Cretaceous of North America indicates that small dinosaur diversity in the latest Cretaceous of North America is likely underestimated due to the difficulty of identifying species from fragmentary fossils.

“It was only through our detailed anatomical and statistical comparisons of the skull bones that we were able to distinguish between Albertavenator and Troodon,” said Thomas Cullen, a Ph.D. student of Evans at the University of Toronto and co-author of the study.

The bones of Albertavenator were found in the badlands surrounding the Royal Tyrrell Museum, which Dr. Currie played a key role in establishing in the early 1980s. The rocks around the museum are the same age as some of the most fossiliferous rocks in the area of the newly erected Philip J. Currie Museum, also named in Dr. Currie’s honour. Although Dr. Currie has also had a several dinosaurs named after him, this is only the second one from Alberta, where he has made his biggest impact.

The fossils of Albertavenator studied by Evans and his team are housed in the collections of the Royal Tyrrell Museum. This is another example of a new species of dinosaur being discovered by re-examining museum research collections, which continually add to our understanding of the evolution of life on Earth. This study suggests that more detailed studies of fragmentary fossils may reveal additional, currently unrecognized, species.

@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev