Brontosaurus
"Brontosaurus" was a large, long-necked quadrupedal animal with a long, whip-like tail, and forelimbs that were slightly shorter than its hindlimbs. The largest species, "B. excelsus", weighed up to and measured up to long from head to tail. For comparison, the current largest land animal, the average male African bush elephant is 3.20 m (10.5 ft) tall at the shoulder and has a body mass of 6,000 kg (13,228 lb) or 6.6 short tons.
Gorgosaurus
"Gorgosaurus" was smaller than "Tyrannosaurus" or "Tarbosaurus", closer in size to "Albertosaurus" and "Daspletosaurus". Adults reached from snout to tail. Paleontologists have estimated full-grown adults to weigh about , perhaps approaching . The largest known skull measures long, just slightly smaller than that of "Daspletosaurus". As in other tyrannosaurids, the skull was large compared to its body size, although chambers within the skull bones and large openings (fenestrae) between bones reduced its weight. "Albertosaurus" and "Gorgosaurus" share proportionally longer and lower skulls than "Daspletosaurus" and other tyrannosaurids. The end of the snout was blunt, and the nasal and parietal bones were fused along the midline of the skull, as in all other members of the family. The eye socket was circular rather than oval or keyhole-shaped as in other tyrannosaurid genera. A tall crest rose from the lacrimal bone in front of each eye, similar to "Albertosaurus" and "Daspletosaurus". Differences in the shape of bones surrounding the brain set "Gorgosaurus" apart from "Albertosaurus".