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.
Aerosaurus
"Aerosaurus" has been recognized as a basal member of the Synapsida, a clade that ultimately produced mammals. Relative to the skull, the body was much larger and the ribs were deeper. The tail was unusually long for a synapsid. Overall Varanopseid pelycosaurs measure about one meter long with fewer maxillary and dentary teeth compared to other Varanops. In "Aerosaurus", the teeth were more laterally compressed creating a strong recurved shape. "Aerosaurus" cranial morphology is distinguishable with its extremely long tooth row, recurved tooth, triangular lateral temporal fenestra. The teeth were so highly curved and compressed that they seem unable to penetrate flesh and the tooth row extended far behind the orbit. The lower teeth were also relatively tiny and such an arrangement suggests "Aerosaurus" was a carnivore. Their limbs were long, and skeleton built lightly suggests they were active and agile. A long low skull and dentition extended far back to lie below the temporal fenestra. "Aerosaurus" had other general features found in ‘Pelycosaurs’ like a slanted Occiput, a lateral temporal fenestra, a septomaxilla bone that contacting the nasal and a maxilla bone contacting the quadrojugal.