Diplodocidae

Diplodocus: This dinosaur gives this group its name; it was 89 feet (27 meters) in length, with an estimated weight of 11 to 12 tons (10 to 11 metric tons).

Apatosaurus: Once commonly known as Brontosaurus, it was shorter and stockier than the Diplodocus; it was also one of the largest land animals that ever existed, measuring over 75 feet (23 meters).

Barosaurus: Similar to Diplodocus, but its cervical vertebrae were 33 percent longer.

The Diplodocus was nearly 90 feet (27 meters) long, weighing in at over 10 tons (9 metric tons), and was one of the largest sauropods to roam Earth (iStock).

Suuwassea: Found in the Morrison formation of the United States, it measured about 46 to 49 feet (14 to 15 meters) in length.

Supersaurus: Another candidate for the longest dinosaur; it is estimated to have been about 108 to 112 feet (33 to 34 meters) long.

Brachiosauridae

Brachiosaurus: This dinosaur gives its name to the group; the largest found fossil of this late Jurassic dinosaur was approximately 82 feet (25 meters) long and 42 feet (13 meters) high, about the height of a four-story building.

Lusotitan: This dinosaur had long forearms; it also averaged about 82 feet (25 meters) long. The most complete fossil found in Portugal did not have a skull, but scientists still believe it was a member of the Brachiosauridae.

Camarasauridae

Camarasaurus: A relatively small sauropod; it was approximately 60 feet (18 meters) long; its forelimbs were not as proportionally long as the brachiosaurids.