These ancient aquatic lizards were warm-blooded, study finds

MAY 9, 2016

by Brett Smith

Paleontologists have debated for years over whether or not ancient lizards called mosasaurs were warm-blooded.

Now, a new paper published in the journal Palaeontology has found that the aquatic lizards were in fact warm-blooded, also known as using “thermoregulation”.

"There was a paper published in Science in 2010 reporting the thermoregulation in marine reptiles at the time of the dinosaurs focusing on the iconic extinct taxa: ichthyosaurs, plesiosaurs and mosasaurs," said author of the new study Alberto Perez-Huerta, an associate professor of geology at the University of Alabama. "This conclusion bothered me a bit because there was not a warm-blooded member organism used for comparison, and we know that size can matter in terms of thermoregulation."

How did the team come to this conclusion?

To reach their conclusion, the study team utilized an oxygen isotope analysis on mosasaur fossils in the University of Alabama's collection and contrasted them to fossils of recognized cold-blooded animals, like fish and turtles, from the same era, as well as the remains of modern warm-blooded organisms like birds.

According to the study, mosasaurs' body-temperatures were similar to the temperatures of contemporary, warm-blooded sea birds, indicating mosasaurs were certainly warm-blooded. The study indicated this tendency toward thermoregulation was regardless of the size of mosasur genus or species. Body size also didn't factor into the results.

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