Avimimus of bird-like features not known in other dinosaurs at the time. In fact, Kurzanov argued that "Avimimus", rather than the famous early bird "Archaeopteryx", was close to the direct ancestor of modern birds, and that "Archaeopteryx" was not as closely related to birds as had previously been suggested. However, this view has not been supported by later phylogenetic analyses of dinosaur and bird relationships. Most modern scientists find that "Avimimus" in fact belongs to a diverse group of bird-like dinosaurs more primitive than "Archaeopteryx", the oviraptorosaurs. Kurzanov placed "Avimimus" in its own family, Avimimidae, in 1981. In 1991, Sankar Chatterjee
Specimens of Archaeopteryx — limiting its ability to perch on branches and implying a terrestrial or trunk-climbing lifestyle. This has been interpreted as evidence of theropod ancestry. In 1988, Gregory S. Paul claimed to have found evidence of a hyperextensible second toe, but this was not verified and accepted by other scientists until the Thermopolis specimen was described. "Until now, the feature was thought to belong only to the species' close relatives, the deinonychosaurs." The Thermopolis Specimen was assigned to "Archaeopteryx siemensii" in 2007. The specimen is considered the most complete and well preserved "Archaeopteryx" remains yet. This specimen first came to light