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.
Nanuqsaurus
"Nanuqsaurus" has been estimated to have been about six meters (twenty feet) long, about half the length of "Tyrannosaurus rex". This diminutive size was postulated by Fiorillo and Tykoski as being an adaptation to its high-latitude habitat.