MOSASAURUS
The Tyrannosaurus rex of the Cretaceous seas, Mosasaurus hoffmannii (moe-za-sore-us hoffman-E) was one of the largest reptiles to ever swim the oceans.
Original Discovery
Mosasaurus fossils were first discovered in the Netherlands in the year 1766. At this time, ideas of extinction and evolution were only speculative thoughts in the heads of a small minority. However, Mosasaurus was definitely unlike any living creature, and the discovery of its fossils would help provide proof of extinction and eventually evolution. Finally in 1822, Mosasaurus was classified as an extinct marine reptile and given its name which means "Meuse River lizard". The species name of hoffmannii honors one of the early discoverers of Mosasaurus. Since then, Mosasaurus fossils have been found across the world, including a recent discovery in the American Mid-West.
Physical Appearance
The appearance of Mosasaurus has changed over time, with early drawings depicting it as a real life sea serpent. That image was refined into the very eel like creature seen above. However, recent discoveries show that all creatures belonging to the family mosasauridae had tails that ended in a fluke. This fluke would have given the tail of Mosasaurus a very shark like look, as can be seen below.
The skull of Mosasaurus is perfectly evolved for grabbing and swallowing prey. Like most animals, Mosasaurus has a row of teeth in both the upper and lower jaw. But, it also possessed a second set of teeth on the roof of its mouth. This set of teeth could have been moved up, down, forward and back. Mosasaurus would have used these teeth to pull small prey down its throat whole.
Ecology
Mosasaurus lived during the late Cretaceous period, in a chronological stage known as the Maastrichtian (ma-strict-tion) 70-65 million years ago. Measuring up to 60 feet in length, Mosasaurus would have been the top predator in oceans across the world. Nothing was off the menu for this giant lizard, if Mosasaurus could grab it, then it was dinner. This menu would have included long and short necked plesiosaurs, giant turtles and fish, and even other mosasaurs. It is thought that Mosasaurus would have traveled in groups, similar to modern whales. These groups would consist of both young and old animals.
Extinction
Like all the marine reptiles alive at the end of the Cretaceous period 65 million years ago, Mosasaurus was wiped out by the giant asteroid that hit the Earth off the coast of the Yucatan Peninsula. This asteroid sent a huge dust cloud into the Earths atmosphere, blocking out most of the Sun's light. Without sunlight the majority of phytoplankton, the foundation of the marine ecosystem, died. This led to a total collapse of the aquatic food chain. When food chains collapse in this way, the animals at the top are hit the hardest. Thus, Mosasaurus was toppled from a throne it could have held till the end of time.
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Image Credits
All images have been cropped to fit the space required
All images are used under Fair Use laws
Image credits are listed from top to bottom and from left to right
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Mosasaurus
Original screenshot by: Liekeze
Taken in game: ARK: Survival Evolved
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Mosasaurus skeleton
Original picture by: Ghedoghedo
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Mosasaurus level 5-10
Original image by: Ludia Inc.
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Mosasaurus hoffmannii
Original image by: Jake/TyrantTR
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Beached Mosasaurus
Original image by: RJ Palmer/arvalis