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.
Diplodocus
"Diplodocus hallorum", known from partial remains, was even larger, and is estimated to have been the size of four elephants. When first described in 1991, discoverer David Gillette calculated it may have been up to 52 m (171 ft) long, making it the longest known dinosaur (excluding those known from exceedingly poor remains, such as "Amphicoelias"). Some weight estimates of this time ranged as high as . The estimated length was later revised downward to and later on to based on findings that show that Gillette had originally misplaced vertebrae 12–19 as vertebrae 20–27. The nearly complete "Diplodocus carnegii" skeleton at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, on which size estimates of "D. hallorum" are mainly based, also was found to have had its 13th tail vertebra come from another dinosaur, throwing off size estimates for "D. hallorum" even further. While dinosaurs such as "Supersaurus" were probably longer, fossil remains of these animals are only fragmentary.