Science, Tech, Math › Animals & Nature Overview of Amphicoelias Share Flipboard Email Print Public Domain Animals & Nature Dinosaurs Herbivores Basics Paleontologists Carnivores Dinosaurs & Birds Marine Reptiles Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated May 31, 2019 Amphicoelias is a case study in the confusion and competitiveness of paleontologists in the late 19th century. The first named species of this sauropod dinosaur is easy to address; judging by its scattered fossil remains, Amphicoelias altus was an 80-foot-long, 50-ton plant eater very similar in build and behavior to the more famous Diplodocus (in fact, some experts believe Amphicoelias altus really was a species of Diplodocus; since the name Amphicoelias was coined first, this may one day occasion a historic renaming of this dinosaur similar to the day when Brontosaurus officially became Apatosaurus). Name: Amphicoelias (Greek for "double hollow"); pronounced AM-fih-SEAL-ee-us Habitat: Woodlands of North America Historical Period: Late Jurassic (150 million years ago) Size and Weight: Up to 200 feet long and 125 tons, but more likely 80 feet long and 50 tons Diet: Plants Distinguishing Characteristics: Enormous size; quadrupedal posture; long neck and tail The confusion and competitiveness pertain to the second named species of Amphicoelias, Amphicoelias fragilis. This dinosaur is represented in the fossil record by a single vertebra measuring five by nine feet long, truly enormous proportions that correspond to a sauropod measuring about 200 feet from head to tail and weighing over 125 tons. Or rather, one should say that Amphicoelias fragilis WAS represented in the fossil record since this gigantic bone subsequently disappeared off the face of the earth while under the care of the famous paleontologist Edward Drinker Cope. (At the time, Cope was embroiled in the notorious Bone Wars with his arch-rival Othniel C. Marsh, and may not have been paying attention to detail.) So was Amphicoelias fragilis the biggest dinosaur that ever lived, heftier even than the current record-holder, Argentinosaurus? Not everyone is convinced, especially since we no longer have that all-important backbone to examine--and the possibility remains that Cope slightly (or greatly) exaggerated his discovery, or perhaps made a typographical error in his papers under the pressure of constant, long-distance scrutiny by Marsh and others in his antagonistic camp. Like another supposedly enormous sauropod, Bruhathkayosaurus, A. fragilis is only provisionally the world-champion dinosaur heavyweight, pending the discovery of more convincing fossil evidence.