It was originally named as an African species of Brachiosaurus (B. brancai), but this has since been changed. If our Giganotosaurus pack had targeted a recently hatched Argentinosaurus rather than a full-grown adult, it might have been successful in its quest. Supersaurus itself has fared a bit better, now estimated at 110 feet and about 45 tons, but the same isn’t true for another childhood favorite of mine. Bruhathkayosaurus, a dinosaur that may have been as big or even bigger than Argentinosaurus, was only known from limb, hip, and tail elements, and those fossils disappeared (much like the near-mythical dinosaur giant Amphicoelias, estimated to be 190 feet long from a long-lost piece of vertebra). John Hurt narrates the facts behind the discovery of huge Argentinosaurus nesting site in modern day Patagonia. Weight is another matter altogether. These gigantic herbivores were about 115 feet long and probably weighed around 73 tons, although some estimates place its weight range around the 85 ton mark. A great deal of a sauropod’s length was in the tail, and how long that tail really was hinges upon how many vertebrae were in that part of the spine. Brachiosaurus is agenusofsauropoddinosaurfrom theJurassicMorrison FormationofNorth America. One dinosaur that might actually have been much bigger than even Argentinosaurus is the potentially colossal Amphicoelias. This scrappy record is important to keep in mind because, among other parts, tails make a big difference in this ongoing “my dinosaur is bigger than yours” contest. Of the two remaining meat-eaters, one has been left dangling almost comically off Argentinosaurus' elongated neck, while the other savagely inflicts grotesque-looking, but mostly superficial, wounds under this titanosaur's massive belly. In 1899 Riggs had sent inquiries to rural locations in the western United States concerning fossil finds, and Bradbury, an amateur collector himself, reported that dinosaur bones had been collected in the area since 1885. Brachiosaurus is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154–153 million years ago. Unfortunately, even 25 or 30 tons of combined force isn't enough to dislodge a 100-ton obstacle, and the Giganotosaurus closest to Argentinosaurus' rump has left itself wide open to a supersonic tail flick to the head, rendering it unconscious. There's no way even the hungriest Giganotosaurus would have been foolhardy enough to attack a full-grown Argentinosaurus; so let's say, for the sake of argument, that an impromptu pack of three adults has teamed up for the job. Summary – Brontosaurus vs Brachiosaurus. Argentinosaurus was a titanosaurian sauropod dinosaur from the Late Cretaceous period. And don’t even get me started on the titanosaur that was heralded in headlines as maybe being the largest of all time despite being known from a single tooth. 1993. As it is, though, the predators fall back warily and allow the wounded Argentinosaurus to walk slowly away, and then proceed to devour their fallen comrade. That’s why paleontologists are familiar with shrinking sauropods. None of this is to say that the newly-discovered sauropod in Argentina is out of the running for the title of the largest dinosaur yet found. Dinosaurs aren’t the only animals to get downsized. Argentinosaurus is a huge dinosaur that was discovered in Argentina in 1987 by Guillermo Heredia. The specimen of the giant marine reptile Pliosaurus nicknamed “Predator X” was initially said to be 50 feet long in documentaries and news items, supposedly the largest pliosaur of all time, but was later downsized to 33-42 feet long. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in the Colorado River valley in western Colorado, United States. Those giant titanosaurs truly were in another league. But there’s no way to say for sure just yet. https://www.nationalgeographic.com/science/phenomena/2014/05/18/biggest-dinosaur-ever-maybe-maybe-not.html. Found by a farm worker in the vicinity of La Flecha, Argentina, and excavated by a crew from the Museo Paleontológico Egidio Feruglio, the 95 million year old site contains over 150 bones belonging to seven individuals of  the same long-necked, heavy-bodied species. Even sauropods known from a decent amount of material are still too incompletely known to get a direct idea of how long and heavy they were. Overall, Brontosaurus is one of the longest dinosaurs while Brachiosaurus is one of the tallest dinosaurs that lived on Earth.