News Paleontologists discover ‘Scotty,’ the world’s largest T. rex fossil: ‘The rex of rexes’ March 26, 2019March 27, 2019 N'dea Yancey-Bragg, USA TODAY Comments Off on Paleontologists discover ‘Scotty,’ the world’s largest T. rex fossil: ‘The rex of rexes’ The massive predator, nicknamed “Scotty,” was about 42 feet long and likely weighed more than 9.7 tons, according to a new study.