I have always felt a bit sorry for
Over the past several decades, numerous enigmatic theropod dinosaurs have been discovered from Cretaceous rocks outside North America. A number of these, such as the recently described Aerosteon , closely resembled Allosaurus. And Aerosteon was not alone. The authors of the new study have placed it together with the theropods Australovenator, Chilantaisaurus, Fukuiraptor, Megaraptor, Neovenator and Orkoraptor in a group called the Neovenatoridae.
If these names sound a bit unfamiliar, it’s because most relatively new dinosaurs are quite new—discovered within the last decade or so—and many of them have been hard to categorize. Megaraptor is a good example: at first, researchers thought that it was an enormous "raptor"-type dinosaur, though later studies suggested that its large claws were a sign that it was related to Spinosaurus. Now we know that it was more like Allosaurus in form and was part of a "hidden" radiation of this type of dinosaur throughout the world during the Cretaceous.
As a group, the Neovenatorid dinosaurs were smaller and more fleet of foot than their well-known relatives the carcharodontosaurids. Both groups are closely related to Allosaurus, being parts of the larger group the Allosauroidea, but they represent different sorts of adaptations. They probably played a very different role as predators in the ecosystems in which they lived.