What Was the Biggest Dinosaur? Fragmentary Fossils Make It Hard to Tell Pinning down the most titanic of the large sauropod dinosaurs is not an easy task, since the odds were generally against the biggest ones being buried and preserved Enormous dinosaurs like the Brachiosaurus in this illustration evolved multiple times over millions of years. dottedhippo via Getty Images Nagatitan was immense. The recently announced titanosaur , the largest dinosaur yet uncovered in Thailand, likely stretched more than 88 feet in length and weighed almost 30 tons. The operative word is “likely,” though, because as big as the dinosaur was, only a smattering of its bones made it into the fossil record. Without a complete skeleton, it’s difficult to tell what the creature’s exact measurements were. The newly named Nagatitan is far from the only large dinosaur whose actual size seems a little hazy.…