“Those two giant arm bones have long amazed researchers. Some suspected the whole beast, which died about 70 million years ago, could have been more than 100 feet long. But the arms were all they had to go on. [...] Then in 2009, Currie’s dream came true.”
▻http://www.npr.org/2014/10/22/357622139/bigger-than-a-t-rex-with-a-ducks-bill-huge-arms-and-a-hump