Tylosaurus

Tylosaurus has a large, strong chest and arms, big flippers, a long body, and a strong tail for swimming. It has a ram-shaped snout and big conical teeth for catching prey. It is a mosasaur, or Meuse River lizard, a true marine lizard. Its food was turtles, plesiosaurs, other mosasaurs, larger fish and shellfish.

Jurassic Park franchise
Tylosaurus does not appear in any Jurassic Park books. However, it does appear in Jurassic Park: The Game which is part of the movie franchise. Tylosaurus also appeared in comics.

Creation
Laura Sorkin wrote in her Journal that Hammond cut half of her research funding for 'urgent needs'. A year later Sorkin saw that the funding was used to build the Marine Facility, a glass viewing dome in an underwater cave. She later saw that it housed a Mosasaur. She wrote that "I'd be pissed off about being kept out of the loop, but I'm too excited to care." She writes that the Mosasaur was the first specimen created and was amazed that it was viable. It was grown in a "breeding tank", it was placed in the lagoon of the Marine Facility because it had outgrown the tank.

On the Tour the Island site there was a blue "InGen" icon on the northern part of the island, next to the North Dock. The icon linked to classified information, the information is locked by a password. The icon links to video footage from two security cameras. The footage shows the Marine Facility with its underwater viewing dome. In the cave swims the Mosasaur Tylosaurus. The information says the Mosasaur, Jurassic Park’s ‘Devil from the deep’, was scheduled for Phase II, 6 months after the opening of the Park. InGen had hired marine animal behaviorists to set up security protocols.

Jurassic Park: The Game
Tylosaurus appears in Jurassic Park: The Game in the scenario Ethics, Part 1. The single Tylosaurus was allowed opportunity to escape into the wild by Dr. Sorkin as a further stake to leverage against the government so that they may not destroy the island. However, it eventually kills her and the gate leading to the ocean is closed again by the three escaping survivors, precluding its escape and leaving it to be destroyed with the dinosaurs.

In The Swim the three protagonists have to outswim the Tylosaurus out of the lagoon. They initially tried to distract the creature with fish, but it noticed them in the end.

Classification
It was originally the unnamed marine reptile in the game, but in the game dialogs it is labeled "Mosasaurus". In Laura Sorkin's research journal, she describes the creature and labels it "Mosasaur". She also writes: "Upwards of 50 feet long, depending on genus." From this text it is clear that she doesn't know its genus, indicating that she calls the creature "Mosasaur", she refers to the to which it belonges; which is  (Mosasauridae).



Jurassic Park III: Park Builder
Tylosaurus is number 127 of the Carnivore Threes that can be created in Jurassic Park III: Park Builder. You can find its DNA pretty easily. You should place it in it's own enclosure, considering that if it gets placed with another animal, it will kill it.

Jurassic Park: Builder
Tylosaurus appears in the underwater park update for the game Jurassic Park: Builder.

Trivia

 * Tylosaurus is the first marine reptile to appear in the film canon.
 * It is one of the few non-dinosaur attractions of Jurassic Park and the franchise (another non-dinosaur are the Pteranodons).
 * It is unknown how the reptile was created. As Gerry Harding said, a mosquito can't exactly suck the blood of a creature that spends its entire life underwater. In Jurassic Park: Builder aquatic reptiles cloned from DNA in frozen aquatic parasites that had fed on reptiles. But that method is impossible in real-life. It is possible that mosquitoes fed on reptiles that was surfacing for air, or from a beached carcass. However, mosquitoes only populate stagnant humid areas rather than coasts. It's more likely that a reptile swam into fresh water in the manner of a bull shark and found itself in a swamp.
 * If you look closely, Tylosaurus appears to have a forked tongue, a characteristic commonly found in modern lizards and snakes. This deciption is usually the main set on how mosasaurs (with the exception of Globidens) may have hunted for food, this may have also proved the distinction that mosasaurs were closely related to modern monitor lizards and snakes
 *  Tylosaurus has spikes on it's body. In real life, there is no evidence that Tylosaurus had spikes on it's body.