SHONISAURUS

Shonisaurus popularis

Etymology: Popular Shoshone mountain lizard

Nickname: "Shoni"

Classification: Ichthyosauria, Shonisauridae

Diet: Carnivore

Size: 15-21 meters long

Provenance: Luning Formation, Nevada, USA - Late Triassic, Norian stage, 227 million years ago

Movie appearances: Jurassic World (2015); Jurassic World: Fallen Kingdom (2018); Jurassic World: Dominion (2022); Jurassic World Rebirth (2025)

Shonisaurus popularis is a species of large marine shonisaurid ichthyosaur that lived in the late Triassic period, some 227 million years ago, in what is now the state of Nevada.

Masrani resurrected Shonisaurus in the early 2000s for the purpose of including it in Jurassic World. Its coloration was greyish-blue with a slightly creamy underbelly. Although a typical Shonisaurus would reach about 13 to 15 meters long, as they kept growing they could reach sizes of up to 21 meters long.

Although its a marine animal, that targets mostly aquatic prey, Shonisaurus has been observed jumping to attack terrestrial prey at the edge of the water, as it was observed with the one resident in Jurassic World that took down the Indominus rex. In Ile Saint-Hubert, the resident Shonisaurus was found attacking boats, and forming a symbiotic relationship with Spinosaurus to aid in capturing its prey.

In Jurassic World, the Shonisaurus lived in a gigantic aquarium, where visitors could see the giant ichthyosaur feeding on sharks at the local Shonisaur Feeding Show, and also see it swim in the underwater observatorium of the aquarium. In 2015, Jurassic World was shut down with the escape of the Indominus rex, and when the hybrid was battling Rexy, the resident Tyrannosaurus rex, and Blue, a Deinonychus, near the edge of the Shonisaurus aquarium, the giant marine reptile lunged out of the water, beaching itself and successfully capturing the hybrid, dragging it to its death underwater.

Some time shortly after this, a team of people ventured to Isla Nublar to retrieve genetic material from the submerged Indominus rex carcass, believing the local Shonisaurus to have starved in its enclosure, but it however turns out the ichthyosaur was alive, perhaps only barely surviving inanition or sustaining itself narrowly by eating any animal that fell into the aquarium or stood too near to its edge; it was then inadvertently released into the open ocean when the gates of the lagoon were left open to let a submarine enter, allowing the ichthyosaur to roam free across the Pacific Ocean.

In 2022, the Department of Prehistoric Wildlife had confirmed sightings of the Shonisaurus in various locations across the Pacific Ocean, near San Francisco, Seattle, the coral reefs of Hawaii, Okinawa, Japan, Kathryn's Hook, Alaska and Auckland, New Zealand, the latter location where it has been strangely been accepting a symbiotic relationship with a pod of orcas to hunt great white sharks.

However, this individual from Jurassic World was not the only Shonisaurus out there, as in Ile Saint-Hubert, in the Caribbean Sea, other resurrected Shonisaurus inhabited its shores, and occasionally strayed away from the surrounding sea and into other areas; one of them eventually was found dead by the locals of a beach of a nearby country. The individual that was left alive near Ile Saint-Hubert retained a tracker by InGen, and when the company went bankrupt, the data of the tracker were sold to Parker-Genix which began targeting the animal. A team of mercenaries led by Martin Krebs, from Parker-Genix, was sent to the island to retrieve genetic material from Shonisaurus, and the ichthyosaur proceeded to leap near the boat and attack it, while Zora Bennett tried to shoot it with a dart to retrieve the material. In spite of them being successful at retrieving the material, the Shonisaurus proceeded to attack the boat, with the aid of a quartet of Spinosaurus that were working alongside it. Duncan Kincaid moves the boat to shallow waters allowing them to escape from the Shonisaurus successfully.

FILM vs. REALITY

DISCLAIMER: Shonisaurus does not show up in the Jurassic Park films, and it is instead, here, meant to be a plausible substitute to the films' Mosasaurus. The film Mosasaurus differs significantly from its real life counterpart. Firstly, Mosasaurus was only about 13 meters long in real life, which contrasts a lot with the film's counterpart which is well over twice that length. The skin of Mosasaurus was covered in very small scales, which is inconsistent with the skin of the film's representation, whose texture most resembles the scutes of crocodilians, instead. The Mosasaurus in the film has teeth that are disposed outside of its mouth when closed, and doesn't have a forked tongue, unlike the real life one, which would also have serrated teeth neatly behind fleshy lips. Additionally, the real life Mosasaurus had teeth in its palate, however those are correctly present in the film's representation. The Mosasaurus in the film is quite elongated, and modern interpretations of Mosasaurus suggest slightly shorter proportions. The real life Mosasaurus might have actually been more coastal dwelling than one might initially think, perhaps even requiring periodic visits to the coast and river mouths to drink freshwater, which contrasts with the perceived pelagic lifestyle of this animal in the films (however, the Mosasaurus in the film is seen visiting coastal regions very frequently, albeit to hunt). Accurately, Mosasaurus would have had a very versatile carnivorous diet, hunting marine invertebrates, sharks and other reptiles, and could most surely breach out of the water at high speeds if necessary, and hunt in coastal or open waters.

Shonisaurus differs from the real life Mosasaurus for being a much bigger marine reptile, adapted for open ocean lifestyles, possessing a more elongated skull, enormous flippers for steering underwater, a deep body and likely a dorsal fin, adopting a more thunniform-like mode of underwater locomotion, as well as having smooth skin without scales. Unlike the film's Mosasaurus, the real life Shonisaurus did not have osteoderms lining its dorso, as a smooth surface would have been preferred to increase hydrodynamics. Shonisaurus would, however, be able to cruise faster underwater speeds than the real life Mosasaurus, which more consistently puts it closer to the film's iteration of the latter. Because Shonisaurus was already one of the largest marine reptiles known, it most promptly fits as a target for Parker-Genix in Jurassic World Rebirth, and makes it a credible threat to large theropods such as Indominus rex, or against large boats. Similarly to the film's Mosasaurus, it would not be expected for Shonisaurus to have a tongue structures beyond a very simple design. It would however be relatively unlikely to expect Shonisaurus to produce loud cetacean-like vocalizations like the ones produced by the film's Mosasaurus.