Scientists who are experts in dinosaur anatomy?

Some sort of Paleontologist.

I don't think there is a specific term. Vertebrate paleontologist with a specialization in dinosaur anatomy and physiology is the only thing that comes to mind.

Virtually any serious vertebrate paleontologist with a specialty in dinosaurs today will also be an expert on the details of dinosaur anatomy. That has been the central focus of dinosaur research for decades now. Two of the most prominent U.S. researchers are Jack Horner and Robert Bakker.

Paleontologist is the accepted term.

I've seen paleobiologist and paleophysiologist used but I'd stick with paleontologist.

There really is no such thing as an expert in dinosaur physiology or anatomy. We have no examples of actual bodies to study. We have no examples of their behavior. The best that we have are some fossilized bones and possibly reasonable guesses regarding some physical capability. Every year they decide that, "Oh that head doesn't really go with that body," or, "That's not a different species, that's a juvenile form."

We don't know what their hemoglobin was like, or if they even had hemoglobin. Maybe it was something different? Whether you are talking about Ancient Human Archaeology regarding non-literate societies or Paleontology we have mostly tiny bits of evidence and then a lot of assumptions based on theories.