Sinosauropteryx
"Sinosauropteryx" was a small bipedal theropod, noted for its short arms, large first finger (thumbs), and long tail. The taxon includes some of the smallest known adult non-avian theropod specimens, with the holotype specimen measuring only in length, including the tail. However, this individual was relatively young. The longest known specimen reaches up to in length, with an estimated weight of .
Allosaurus
"Allosaurus" was a typical large theropod, having a massive skull on a short neck, a long tail and reduced forelimbs. "Allosaurus fragilis", the best-known species, had an average length of , with the largest definitive "Allosaurus" specimen (AMNH 680) estimated at long, and an estimated weight of . In his 1976 monograph on "Allosaurus", James H. Madsen mentioned a range of bone sizes which he interpreted to show a maximum length of . As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between , , and for modal adult weight (not maximum). John Foster, a specialist on the Morrison Formation, suggests that is reasonable for large adults of "A. fragilis", but that is a closer estimate for individuals represented by the average-sized thigh bones he has measured. Using the subadult specimen nicknamed "Big Al", researchers using computer modelling arrived at a best estimate of for the individual, but by varying parameters they found a range from approximately to approximately .