>>13902662Turns out the sole proponent of exclusive scarvenging behaviour on Tyrannosaurus did an ecological study on that. Conclusion: Tyrannosaurus had to be a predator. BY THE GUY WHO SAID IT WAS A SCARVENGER.
And, arms you say? The degree of motion of theropod arms is oh so limited, the most dextrous of them all is the bird wing. Meathooks at most, but the jaws in EVERYTHING would most of the job. Oh, and useless for getting off the ground, seeing how they were locked with the palms facing each other. However, having the center of gravity in the middle of your lenght and just above the strongest legs ever for an animal its size made Tyrannosaurus quite easy to get up using just its legs.
BTW, you know Giganotosaurus, the Tyrannosaurus-sized Allosaur? Turns out it also had reduced arms. And Abelisaurs had their forearm merged into their wrists.
All in all, arms in giant theropods were just accessory, and the trend was to reduce them as size increased.
Oh, and Allosaurus lithe? Well, the leg proportions point torwards a less cursorial animal than Tyrannosaurus, even when using the huge-ass Tyrannosaurus specimens and the average Allosaurus.
There's a reason Allosaurus lived with not one, but two other competitors (Ceratosaurus and Torvosaurus are both in its size range) while the second largest predatory dinosaur in the range of Tyrannosaurus was fucking beaver-sized (Quetzalcoatlys nonwithstanding, but Quetz wouldn't try to munch on an Edmontosaur)
