Courtesy University of CalgaryPaleontologists at the University of Calgary in Canada have described the smallest carnivorous dinosaur found yet in North America. Hesperonychus elizabethae was a small therapod about half the size of a house cat that more-than-likely feasted on insects, small mammals, and maybe even other small dinosaurs.
Remains of Heperonychus were discovered in 1982 in several places including Dinosaur Provincial Park in Alberta, and stored away as insignificant lizard remains among the collections at the University of Calgary for 25 years.
Nick Longrich, a paleontology research associate in the University of Calgary’s Department of Biological Sciences re-discovered the fossils a couple years ago and along with paleontologist Philip Currie determined the remains were those of a dinosaur rather than a lizard. The bones were closely compared against the recently discovered Asian microraptors, and help fill a glaring gap in the Cretaceous era environment in North America where large carnivores such as Tyrannosaurus rex and Albertasaurus dominated not only the landscape but the fossil record as well.
“Its discovery just emphasizes how little we actually know, and it raises the possibility that there are even smaller ones out there, waiting to be found,” said Nick Longrich. “Small carnivorous dinosaurs seemed to be completely absent from the environment, which seemed bizarre because today, the small carnivores outnumber the big ones. It turns out that they were here and they played a more important role in the ecosystem than we realized. So for the past 100 years, we've completely overlooked a major part of North America's dinosaur community."
Here’s a Nick Longrich explaining his discovery on a University of Calgary video.
Longrich’s and Currie’s study appeared yesterday in the current online issue of the journal of the Proceedings of the National Academy of Sciences.