The monsters are prehistoric flying reptiles. The claim they had feathers is refuted in a new study – see https://phys.org/news/2020-09-naked-prehistoric-monsters-evidence-reptil… … on the basis they are reptiles rather than dinosaurs. Sterosaurus, a smooth skinned flying reptile.
At https://phys.org/news/2020-09-dinosaur-feather-debunked-overwhelming-evi… … a new study claims the first fossil feather said to belong to an Archaeopteryx, a bird like dinosaur, was not so. Not the same story as above but somewhat revealing on how rivalry exists between palaeontologists.
At https://phys.org/news/2020-09-reveals-reptiles-ancient-seas.html … new research is said to prove that while dinosaurs dominated the land, reptiles ruled the roost in the seas and oceans. These include crocodiles, turtles, giant lizards, ichthyosaurs and plesiosaurs. They claim to have reconstructed a pecking order and feeding differences between each, a separate niche in nature if you like. They mention something interesting about the ichthyosaurs. They claim they were originally semi terrestrial, at the beginning of the Triassic. This sounds very much like theories on whales, sea mammals that are supposed to have a terrestrial origin.