Marine dinosaurs evolved extremely quickly, study finds

MAY 22, 2016

by Susanna Pilny

Hundreds of millions of years ago, marine reptiles like the ichthyosaurs and plesiosaurs ruled the seas—but researchers were never quite sure about their origins, or their rise to dominance. Now, research published from paleobiologists from the University of Bristol has shed some light on their mysterious past.

As told in their paper in Paleobiology, the scientists have uncovered evidence that during the Mesozoic-- an era about 252 to 66 million years ago—these predators suddenly burst onto the scene, instead of a slow evolution into their environment.

"We show that when marine reptiles first entered the oceans in the Triassic period, they rapidly became very diverse and had many morphological adaptations related to feeding on varied prey,” said the lead author of the study, Dr. Tom Stubbs, in a statement.

“Within a relatively short space of time, marine reptiles began feeding on hard-shelled invertebrates, fast-moving fish and other large marine reptiles. The range of feeding-related morphological adaptations seen in Triassic marine reptiles was never exceeded later in the Mesozoic."

Studying the fossil record

The team came to these conclusions after carefully studying the fossil record of Mesozoic marine reptiles and using statistic to quantify the variation in the shape and function of jaws and teeth across these predators. Before now, studies had mostly been based on estimates of biodiversity across time. But this new study shook things up by tying the shape of jaws and teeth to their different modes of life (like their different modes of feeding).

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