What is the name for a scientist who studies dinosaurs?

A person who studies reptiles and amphibians is known as "herpetologist." However, a "batrachologist" is someone who's study focuses solely on amphibians.

Herpetologists study reptiles and amphibians. It comes from the Greek term for a "creeping animal" and uses the ending -ology that is used to notate that it is the study of something.