MOSA
SAURS
Age of Mosasaurs
Acknowledgeable Species
The LARGEST of them ALL
Hainosaurus
AND MORE SPECIES!
Ectenosaurus: They had very well-preserved skin compared to other species.
Eonatator and Halisaurus: were one of the earliest mosasaurs.
Globidens: They Had unusually round teeth.
Goronyosaurus: Has crocodile like behaviour.
Mosasaurus: First species of mosasaurs discovered and named.
Pannoniasaurus: First identified freshwater mosasaur.
Platecarpus: Most common mosasaur found in North America.
Plotosaurus: Pinnacle of mosasaur evolution.
While we know that mosasaurs were big, there was actually a mosasaur that was considered to be the biggest- the Hainosaurus. Hainosaurus is an extinct genus of the marine lizard, also known as the mosasaur. The debate of the true size of mosasaurs is very evident, and the size of the Hainosaurus has also been debated and revised many times. It was first estimated to be 17 metres long, which was then revised to 15 metres in the 1990s. Recently, the size was further revised to 12.2 metres by Johan Lindgren.
Hainosaurus was one of the top marine predators of the Late Cretaceous. This giant predator feasted on: turtles, plesiosaurs, pterosaurs, fish, ammonites, cephalopods, sharks, and even smaller mosasaurs.
They were apex predators of the Earth’s oceans in the last 25 million years of the Late Cretaceous. Returning to the sea during Cenomanian - Turonian time. By the end of the Cretaceous, two genera of mosasaurs (Mosasaurus and Hainosaurus) had grown to lengths of more than 15 m, and represented a group of marine carnivores that were as dominant in their environment, as Tyrannosaurus rex was on land. Unlike the T-rex, these giant mosasaurs were more widely distributed geographically and more numerous.
During Maastrichtian time, mosasaurs were diversifying rapidly and entering many niches left vacant by the extinction of other marine species, and they were beginning to enter freshwater environments. From their fossil record, it is evident that mosasaurs were a highly successful group that became the apex predators of the Earth’s oceans rather suddenly during the Late Cretaceous. However, they may have become too specialized, or other factors may have contributed to their extinction at the end of the cretaceous period (during the K-T event), read more about their extinction here.
In order to settle the debate of the size of Hainosaurus, paleontologists would have to discover an exceptionally well preserved fossil specimen that is also fully grown. Lingering questions like these is what pushes paleontologists and it’s what makes the the study of fossils such a growing and buildable discipline.
Whether it was the initially thought 17 m or recently found 12 m, Hainosaurus was still amongst the biggest predators in the seas of the late Cretaceous. See the comparison photo above that shows the Giant Mosasaur in comparison to other well known ocean predators.
Hainosaurus was a gigantic marine reptile and had to eat a lot to satisfy its hunger. This made the Hainosaurus a generalist, a non-picky eater, which meant it featest on other marine organisms such as: smaller mosasaurs, turtles, plesiosaurs, large fish and sharks. While it was growing and reaching adult size, the Hainosaurus would have eaten a diet of smaller animals such as birds and ammonites.
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Giant mosasaur is shown in comparison to other well known marine predators.
A time line of the mosasaurs' existence.