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.
Tylosaurus
Along with plesiosaurs, sharks, fish, and other mosasaurs, "Tylosaurus" was a dominant predator of the Western Interior Seaway during the Late Cretaceous. The genus was among the largest of the mosasaurs (along with "Mosasaurus hoffmannii"), with the possibly conspecific "Hainosaurus bernardi" reaching lengths up to , and "T. pembinensis" reaching comparable sizes. "T. proriger", the largest species of "Tylosaurus", reached lengths of about .