Scientists working on the project discerned from the sample that the tail likely belonged to a juvenile
coelurosaur. The dinosaur the tail was attached to was part of a group of theropod dinosaurs-a categorization that includes everything from tyrannosaurs to modern birds.
The skeletal remains represent a new species of
coelurosaur, the clade containing all theropod dinosaurs including T.
Kirkland describes the new predator, a yet-unnamed type of
Coelurosaur, as "the coyote of the Cretaceous." Like coyotes, he speculates, it consumed a variety of prey.
The Chinese fossil seems closely related to the
coelurosaur Compsagnathus, one of the smallest dinosaurs.
This was most likely a
coelurosaur, a bird-like biped that reached about 8 feet in length, Weems says.
But this feathering has only been found in theropods that are classified as
coelurosaurs, a diverse group including animals like T.
By the close of the Cretaceous, however, Asia sported a large theropod fauna of tyrannosaurids and other large
coelurosaurs that was similar to faunas in North America, but drastically different from those on the southern continents (Africa, South America, India, Madagascar, Australia).
Of course, the presence of "protofeathers" (and "true" feathers) in non-avialan
coelurosaurs (such as Dilong paradoxus, Sinosauropteryx prima, and many others) still puts the origin of feathers before the origin of flight and suggests that the original function of these structures was for thermoregulation.
Now, it appears that tyrannosaurs evolved much earlier than that, from a group of small, meat-eating dinos called
coelurosaurs.
rex and its cousins evolved much earlier, from a line of small, meat-eating
coelurosaurs. Fossils show that these creatures shared many skeletal features with tyrannosaurs.
* Tyrannosaurs belong to a broader, diverse group of dinosaurs known as the
coelurosaurs. Most paleontologists believe this group gave rise to birds.
Reduction in tail size is first seen in
coelurosaurs such as ornithomimids and dromaeosaurs (Gauthier 1986; Gatesy 1990, 1994), which have tails of smaller diameter and fewer segments [ILLUSTRATION FOR FIGURE 6 OMITTED].
