What is the pterodactyls enemies?

Answer 1

small ones where mainly attacked dinosaurs such ornitholestes and other samll theropods and crocodiles for the big ones they attacked by mosasaurs such as tylosaurus and hainosaurus and pliosaurs such kronosaurus

Answer 2

They are extinct, so have no predators at this time. When they were alive, people were not, so we cannot say what predator (if any) preyed on them.