The star of this study, 'Big Al', is an 150 million year old (late Jurassic) fossil Allosaurus skeleton from the Morrison Formation in the USA. The authors looked for muscle attachment sites on the bones, combined with comparisons to modern birds and crocodiles anatomy, then digitally re-created the soft tissue around the neck and head.
Archer: Woodhouse! What are you doing?!
Woodhouse: Uh, sitting down, sir.
Archer: What, at the table?!
Archer: Like people?!
Archer: What?! Look, he thinks he's people!