Mosasaurs had fierce survival strategies including cannibalism

Mosasaurs are extinct marine reptiles that hold a remarkable place in the history of vertebrate paleontology. Their discovery in 1766 near Maastricht, Netherlands, laid the foundation for studying fossilized backboned animals.

Palaeontologist Michael Polcyn, a leading expert on mosasaurs, has presented the most comprehensive research to date on their early evolution and ecology. On December 16, Polcyn will receive his PhD from Utrecht University for his extensive studies into these fascinating marine reptiles.

Evolution of mosasaurs

“Mosasaurs are a textbook example of macroevolution, the emergence of new and distinct groups of animals, above the level of species,” Polcyn explained.

“Although they have been studied for centuries, new discoveries, novel research approaches, and the application of technology, are still teaching us about their relationships and behaviors, some of which continues to surprise us.”

“For example, through the use of detailed comparative anatomy aided by micro-CT scanning technology, we have gained a much better understanding of what group of lizards mosasaurs likely evolved from.”

A new look at ancient mysteries

Polcyn used state-of-the-art imaging technologies, such as micro-CT scans, to study the braincase structures of mosasaurs.

These tools not only clarified the evolutionary relationships of mosasaurs but also resolved debates around problematic fossil taxa. This approach provided a better understanding of their origins and evolutionary adaptations.

“This study not only addressed the early evolution of the group, but also explored small- and large-scale aspects of their feeding biology,” said Polcyn.

A notable highlight of his work involves a specimen found in Angola, which contained the remains of three other mosasaurs in its stomach, including one from the same species.

This extraordinary discovery represented the first known instance of cannibalism in mosasaurs.

Mosasaurs adapting to life in the sea

Mosasaurs evolved from a group of lizards that ventured into the oceans around 100 million years ago. Over 34 million years, they adapted to a wide range of marine environments, occupying diverse ecological niches.

Alongside many other species, mosasaurs were wiped out 66 million years ago during the mass extinction caused by a meteorite impact.

Despite extensive fossil records from their later evolutionary stages, little is known about the early history of mosasaurs.

New discoveries and historical specimens

“A relatively large number of fossils are known from the second half of the evolutionary history of mosasaurs, allowing a good understanding of the relationships among those species, which have been classified into four major groups,” Polcyn noted.

“Much less is known about their early evolutionary history, and how those major groups are related to one another, their origins, and the origin of mosasaurs as a whole.”

To address these gaps, the team from Utrecht University leveraged advanced imaging techniques to analyze both new discoveries and historical specimens.

The findings resolved a long-standing scientific debate. Polcyn concluded that mosasaurs are more closely related to monitor lizards than to snakes.

Mosasaurs’ feeding behavior and cannibalism

The feeding habits of mosasaurs were also a focal point of Polcyn’s research. The Angola specimen containing three mosasaurs highlights a unique aspect of their predatory behavior.

“Whether that mosasaur was a scavenger or actively hunted its prey cannot be said with certainty; however, we do have the first documented example of cannibalism in mosasaurs,” Polcyn explained. His findings also reveal how mosasaurs processed prey and the relationship between predator and prey sizes.

Polcyn’s dissertation includes a comprehensive study of mosasaur feeding behavior over a period spanning 92 to 66 million years.

By analyzing a vast global dataset, he uncovered patterns of foraging area segregation and feeding diversity. These insights illuminate how mosasaurs divided resources and evolved their dietary strategies.

A legacy of discovery

Michael Polcyn’s research not only enhances our understanding of mosasaur evolution but also highlights the value of integrating advanced technology with paleontological studies.

His findings continue to reshape our understanding of these ancient marine predators, offering a deeper glimpse into their complex lives and ecological roles.

As new discoveries emerge, the legacy of mosasaurs serves as a testament to the dynamic nature of paleontology. Their story reminds us how ancient ecosystems still hold untapped secrets waiting to be uncovered.

Image Credit: Andrey Atuchin

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