Sauroposeidon
The press release in 1999 immediately garnered international media attention, which led to many (inaccurate) news reports of "the largest dinosaur ever!". While "Sauroposeidon" likely represents the tallest known dinosaur taxon, it does not hold records for either the longest or most massive. "Patagotitan" or "Argentinosaurus" make better candidates for the title "World's Largest Dinosaur" (presuming to ignore, as is conventional, "Amphicoelias"), though incomplete fossil evidence makes exact rankings impossible.
Dreadnoughtus
Dreadnoughtus is a genus of giant titanosaurian sauropod dinosaur containing a single species, Dreadnoughtus schrani. "D. schrani" is known from two partial skeletons discovered in Upper Cretaceous (Campanian-Maastrichtian; 84–66 Ma) rocks of the Cerro Fortaleza Formation in Santa Cruz Province, Argentina. It is one of the largest of all known terrestrial vertebrates, possessing the greatest mass of any land animal that can be calculated with reasonable certainty. "D. schrani" is known from a more complete skeleton than any other gigantic titanosaurian.