Fallen Kingdom takes place three years after the demise of the Jurassic World theme park on Isla Nublar, the dinosaurs roam freely and try to fight to survive on the island until a volcanic eruption from Mount Sibo threatens their existence. On Isla Nublar, a group of mercenaries are sent to recover the bones of the Indominus rex from the Jurassic World lagoon for at the time unspecified purposes. A submersible is sent down to retrieve the bones, and it sends them up on a buoy before it is attacked by the Mosasaurus. The people on land who opened the gate to the lagoon lose contact with the submarine pilots. The surface team has their own problems as well, as when Isla Nublar's veteran Tyrannosaurus rex attacks the group, they have to grab the I. rex fragment and get out as soon as possible. One man is left on the ground and their helicopter lets down a rope ladder. They escape the Tyrannosaurus but the man on the rope ladder is swallowed by the Mosasaurus after it jumps into the air, and the Mosasaurus escapes into the open ocean. I will address the anatomical problems with Rexy later, so for now, I will focus on the inaccuracies of the Mosasaurus. While commonly labeled “aquatic dinosaurs” by pop culture, mosasaurs are not dinosaurs, their taxonomic alignment is within Squamata, which includes lizards and snakes, more spefically, monitor lizards. In this model of the Mosasaurus, there are several problems with its anatomy: first being the the tail is wrong, a Prognathodon specimen had an impression that resembles a tail fluke like in other marine vertebrates. A tail fluke would allow a mosasaur to swim faster to catch prey, which includes whatever animals can fit in its massive jaws or cannot swim away. Second, because of their close relationship with monitor lizards (which have forked tongues to taste the air for traces of prey), Mosasaurus should also have a forked tongue for the same reasons. Third, melanosomes (pigment cells) in the scales on a Platecarpus specimen indicate that mosasaurs had countershading, which is a coloration pattern with darker color on top, and lighter on the bottom, making it harder for prey (and predators for smaller mosasaurs like Globidens and Cliadestes) to see them. Sharks, cetaceans, pelagic fishes, penguins, and Leatherback Turtles also have this coloration. The last anatomical inaccuracy I have to point out are the osteoderm ridges, which no living or extinct squamate has, the scales overlap.