A new species of miniature meat-eating dinosaur has been discovered in North America, where it is the smallest-known dinosaur. Hesperonychus elizabethae was half the size of a modern day house cat and it ran around on two legs hunting for insects and other small animals like frogs and mammals and possibly even baby dinosaurs.
This is the discovery of two Canadian palaeontologists, Nick Longrich from the University of Calgary and Philip Currie from the University of Alberta, in a study published in the Proceedings of the National Academy of Sciences.
This newly discovered species looked a little like the velociraptors made famous by the movie Jurassic Park, but much smaller. Their name Hesperonychus means ‘western claw’ because of the razor-sharp, sickle-shaped claws on its second toe. They were about 50cm tall, with a slender head and dagger-like teeth. They lived in marshes and swamps that covered parts of Canada during the Cretaceous period between about 145 and 65 million years ago.
The fossils were originally collected in 1982 and the most important specimen was a pelvis bone collected by a well-known Canadian palaeontologist Elizabeth Nicholls, who died in 2004 and after who this new dinosaur was named. But the bones remained in storage and unstudied until Longrich came across them in 2007.
Originally they did think the fossilized claws were from young dinosaurs but when they started studying the pelvis bone they found that the hipbones were fused which would have only happened when the animal was fully grown.
These small carnivores were in fact quite common, a discovery that unveils how for the last hundred years palaeontologists have been missing an important part of these ancient ecosystems. It raises the possibility that there could be even smaller meat-eaters out there waiting to be found.