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.
Segisaurus
"Segisaurus" lived about 183 million years ago during the Jurassic period. "Segisaurus" was roughly the size of a goose and was a primitive bipedal theropod. "Segisaurus" was roughly 1 meter (3.3 feet) long, half a meter (1.65 feet) tall and weighed about 4-7 kilograms. It was nimble and insectivorous, although it may have scavenged meat also. It was bird-like in structure, with a flexible, elongated neck and stout body. "Segisaurus" was three-toed and had powerful legs that were long compared to its body length. Like its legs, "Segisaurus" had a long tail and long forearms. Its collar bone was not unlike a bird's, thus strengthening scientists' arguments that dinosaurs were related to avians. "Segisaurus" is described from the only specimen ever found, the holotype UCMP 32101, which was a sub-adult. The full size of "Segisaurus" as an adult may never be known. Strangely, clavicles were found on the "Segisaurus" specimen, which were unknown in other dinosaurs from that era. A speculative interpretation by Charles Lewis Camp was that the "splint-like" neck ribs supported a "Draco"-like patagium along the neck, to improve the animal's ability to move quickly. "Segisaurus" is significant because it demonstrates that the clavicle was primitively present in early theropods.