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 .
Sinosauropteryx
The specimen NIGP 127587 was preserved with the remains of a lizard in its gut region, indicating that small, fast-moving animals made up part of the diet of "Sinosauropteryx prima". Numerous lizards of this type have been found in the same rocks as "Sinosauropteryx". These lizards have been interpreted as most likely belonging to the genus "Dalinghosaurus". "Dalinghosaurus" was probably a fast-running lizard adapted to living in open habitats, much like "Sinosauropteryx" itself.