Sinosauropteryx
"Sinosauropteryx" was a small bipedal theropod, noted for its short arms, large first finger (thumbs), and long tail. The taxon includes some of the smallest known adult non-avian theropod specimens, with the holotype specimen measuring only in length, including the tail. However, this individual was relatively young. The longest known specimen reaches up to in length, with an estimated weight of .
Shuangbaisaurus
"Shuangbaisaurus" had a relatively robust (compared to "Sinosaurus") skull, with a length of and a length/height ratio of 2.84, not including the thin paired crests that were present at least above the eye sockets. These crests are incompletely preserved, but appeared to have been formed mostly from the frontal bone, as well as possibly the postorbital and prefrontal bones. The crests may have extended further forward, over the nasal and lacrimal bones. Similar crests are seen in "Dilophosaurus" and "Sinosaurus"; however, the crests of "Sinosaurus" do not extend over the eyes, thus differentiating it from "Shuangbaisaurus".