Mosasaurus

Current model

"*In the vast Western Interior Seaway lives a much more impressive type of reptile. Despite its gargantuan size and fearsome appearance, Mosasaurus is not a dinosaur, or even closely related to them. It is, in fact, a type of giant marine lizard that was restricted to the Cretaceous period. There has been much argument as to where mosasaurs fall within the lizard family tree, but some recent compelling evidence suggests they may be most closely related to snakes among living groups. Fossil evidence of giant mosasaurs in Hell Creek has only very recently been uncovered, but they are also known from the underlying Fox Hills formation.*"

―*Saurian: A Field Guide to Hell Creek*

***Mosasaurus*** is a genus of mosasaur, giant aquatic squamates that roamed the seas of the Late Cretaceous period. *Mosasaurus* have been found in parts of Europe and North America, but also South America, Africa, Asia and Antarctica, implying this was a cosmopolitan genus. While no *Mosasaurus* fossils are known specifically from Hell Creek, it was alive at the end of the Maastrichtian and lived in the neighboring Western Interior Seaway, so it's presence on the Hell Creek coast is perfectly plausible. Mosasaur fossils have recently been found in Hell Creek, indicating that giant mosasaurs were present in the formation's coast and even visited its riverine courses.

*Mosasaurus* was one of the first mosasaurs to be discovered. They were very robust compared to other large mosasaurids as well as more robust skulls implying a stronger bite. They were believed to feed on various marine life including ammonites, sea turtles, hesperornithids, plesiosaurians, and even other mosasaurids as it was a highly aggressive hunter.

The true size of the *Mosasaurus* has been a matter of debate. Although old estimates supported a 17 meter length, new estimates, based on reportedly more accurate references, suggest a maximum length of 12-13 meters for the largest *Mosasaurus*.

## Physical Appearance

*Mosasaurus* is dark grey with a lighter underbelly and subtle striping on the sides. This coloration, with a dark top and lighter belly, is common to some aquatic animals, namely sharks and dolphins.

Mosasaurs are known to have had tail flukes, used for propulsion. Saurian's *Mosasaurus* also has a forked tongue, likely because its closest living relatives, the snakes, do.

These animals may have lurked and pounced rapidly and powerfully on passing prey, rather than chasing after it.

## In *Saurian*

*Mosasaurus* appears in the game. *Mosasaurus* was added for a particular function: to keep the player from swimming out too far into the ocean. If the player goes out too far, they will be eaten by the *Mosasaurus*, preventing them from reaching the edge of *Saurian*'s map. *Mosasaurus*' only other appearance in the game is as a beached carcass, though that is a rare event. *Mosasaurus* spawns every time the player comes too close to the deeper waters, but can also be observed taking down other AI creatures who make the same mistake. The player is able to dodge a *Mosasaurus* attack by swimming back to the beach, if it is close enough for the sea monster to give up on the chase. The *Mosasaurus* is an unusual AI creature in the game, given that it only spawns when a creature comes to the ocean, and that it is impossible for one to be taken down either by the player or by another creature. *Mosasaurus* doesn't die of thirst or hunger in the game. It's also the only animal in the game that is absent from the encyclopedia. *Mosasaurus* carcasses are not the result of once-living *Mosasaurus* dying, but rather a carcass that spawns on the beach, waiting for another animal to feast on its meat. *Mosasaurus* kills players and other AI animals with just one hit, no matter which species or life stage. Currently, *Mosasaurus* doesn't have sexual dimorphism or ontogenic stages.

### *Dakotaraptor* gameplay

Living *Mosasaurus* are dangerous animals for a *Dakotaraptor*, being able to sneak in, under the ocean and kill the player in one hit. In rare occasions, *Mosasaurus* carcasses appear on the beach, allowing the *Dakotaraptor* to have a free meal.

### *Triceratops* gameplay

*Mosasaurus* are dangerous animals for *Triceratops*, being able to kill them in one hit.

## Behind the Scenes

The first design by Alex "Doc" Lewko depicted it as having a color scheme similar to most depictions following the study "Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles" by Johan Lindgren et al. with the upper body being black and the underbelly being white. The body of this design was slender and serpentine-like most depictions of *Mosasaurus*.

The *Mosasaurus* saw a later-now scrapped design-by RJ Palmer. Palmer's design was bulkier and shorter with a dorsal fin. Also worth noting, was that the coloration of the Palmer designs *Mosasaurus* was more vibrant than what the findings by Lindgren et al. suggest. The most commonly seen color of Palmer's colorations being a brown with a spotted pattern with vertical lines. The reason why the colorations did not reflect the 2014 findings was that the concepts were done a year before in 2013. Parker has stated that these designs of the *Mosasaurus* were not temporary and the game developers were seeking for more options before settling on a final design.

Indeed, *Mosasaurus* later received a third design and model in 2017. RJ Palmer created the concept art for this design and was modeled by Jake Baardse under the guidance of paleontologist Nathan Van Vranken.

It is stated that the *Mosasaurus* in game is impossible to kill.

## Gallery

Unused designAlternate unused design 1Alternate unused design 2Alternate unused design 3Beached *Mosasaurus* concept*Mosasaurus* swimming concpet*Mosasaurus* concept artBaby *Dakotaraptor* swimming with mosasaurMosasaur beached*Mosasaurus* CGI modelBeached *Mosasaurus* close to an adult *Dakotaraptor*Adult *Dakotaraptor* swimming away from a *Mosasaurus*
## References

1. ↑ 1.0 1.1 1.2 1.3 Tomozasaurus. (January 19, 2017) Saurian DevLog #12 – Maastrichtian Lurker Shark. *Saurian Website*.
2. ↑ Comments on *Saurian* Facebook Page.
**Brian Choo:** Dig that mosasaur! - although the colouration may be a little over the top based on Lindgren et al.'s report on mosasaur fossil pigment (Nature 506, 484–488)
**Saurian:** We agree, these concepts were done before said publication.
3. ↑ Mosasaurus 001. *ModDB*. Retrieved September 11, 2016