Sinosauropteryx
Three specimens have been assigned to "Sinosauropteryx prima": the holotype GMV 2123 (and its counter slab [opposite face], NIGP 127586), NIGP 127587, and D 2141. Another specimen, IVPP V14202, was assigned to the genus but not to the only species by Zhang and colleagues. The assignment of an additional larger specimen to "S. prima", GMV 2124, was later found to be in error. All of the fossils were found in the Jianshangou or Dawangzhangzi Beds of the Yixian Formation in the Beipiao and Lingyuan regions of Liaoning, China. These fossil beds have been dated to 124.6–122 million years ago, during the early Aptian stage of the Early Cretaceous.
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.