Among the Sauropods, thereare a few individuals of special interest based on their enormous size, as compared to the rest of the Sauropods.

First, we have Supersaurus(Super lizard), of the family Diplodocidae, which was over 20m high, 30m long, and reached a weight of over 50 tonnes. A late Jurassic specimen was unearthed in Colorado in 1972 by "Dinosaur Jim" Jensen. The neck of the specimen was 39 feet in length and a shoulder bone was uncovered that was 8 feet long. (Top right image of Supersaurus leg courtesy of The University of Frankfurt).

Next, we have Seismosaurus(Earth shaking lizard), the largest of all sauropods found to date. It could grow to a height greater than 25m, reach a length of more than 45m, and could weigh a whopping 90 tonnes. In 1979 two hikers came across some peculiar bones in the desert of New Mexico in the Bushy Basin Member of the Morrison Formation. Paleontologist, David D. Gillette was put in charge of unearthing the specimen which he named "Sam" and placed in a new genus Seismosaurus. Although closely related to Diplodous, Seismosaurus had a larger tail and a more massive pelvis. Along with the bones were found a handful of plum sized gastroliths which were highly polished. (Bottom right image of Seismosaurus courtesy of Jeff's Dinosaur Art Gallery).

Finally, we have Ultrasauros(Ultra lizard), of the family Brachiosauridae, which was slightly shorter than Supersaurus only reaching a height of about 16m. It was about the same length as Supersaurus(30m), but it could weigh more than 60 tonnes. A late Jurassic specimen of this beast was also found by Jim Jensen at the same location in Colorado as the Supersaurus specimen. Ultrasauros was previously called Ultrasaurus, but its name was changed because the name was already being used to describe a South Korean specimen. It is thought by many that Ultrasauros may just be a large Brachiosaurus.