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.
St. Louis Museum
A museum specimen of particular note was a fossil, the Zeuglodon, which the Complete Guide to the St. Louis Museum called "the greatest fossil in the world." The Zeuglodon was discovered in 1848 in a field in Alabama. After it was extricated from the rock in which it was found, Dr. Koch purchased the fossil for the St. Louis Museum. The fossilized animal was amphibious and resembled a whale, alligator, and serpent. Only one other fossil of this animal was known to exist at the time, which was owned by the King of Prussia. Previously a Mastodon fossil was the largest one discovered, at 20 feet. The Zeuglodon measured 96 feet. Though some doubted the authenticity of the specimen, Professor Joseph Leidy, M.D. of the University of Pennsylvania and Curator of the Academy of Natural Sciences of Philadelphia and Professor Silliman of Yale College both attested to the authenticity of the fossil.