Sinosauropteryx
"Sinosauropteryx" was a small theropod with an unusually long tail and short arms. The longest known specimen reaches up to in length, with an estimated weight of It was a close relative of the similar but older genus "Compsognathus", both genera belonging to the family Compsognathidae. Only one species of "Sinosauropteryx" has been named: "S. prima", meaning "first" in reference to its status as the first feathered non-avialian dinosaur species discovered. Three specimens have been described. The third specimen previously assigned to this genus represents either a second, as-yet unnamed species or a distinct, related genus.
Pneumatoraptor
"Pneumatoraptor" differs from other theropods in having a narrow shoulder blade that is nearly circular in cross section, as well as having a large opening in the bone to house a hollow air sac cavity. The bone is small, indicating that the animal was only about half the size of the related "Sinornithosaurus" or 0.73 m (2.2 ft). The shoulder girdle is L-shaped, showing it to be a member of the group Paraves, which also includes the dromaeosaurids, troodontids, and birds. While the "Pneumatoraptor" remains are too incomplete to tell which, if any, of these specific groups it belongs to, many of the bones features are similar to dromaeosaurids.