Crossword Genius

Sue at Chicago's Field Museum, e.g (4)

Ross

I believe the answer is:

trex

(Another definition for trex that I've seen is " Long, difficult journey".)

I've seen this clue in The New York Times.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.