Ichthyosaurs had specialized diets to peacefully coexist

Over 200 years ago, Ichthyosaurs were discovered by Mary Anning at Lyme Regis, England. Anning sold the first Ichthyosaur fossil she found for enough money to support her family for six months and thus began her life as a celebrated commercial paleontologist.

Ichthyosaur means “fish lizard,” reflecting the different features embodied by the animal, which seems to almost be a reptilian dolphin. Although all Ichthyosaurs share similar traits, there are differences as well. Some of Anning’s specimens have long, slender snouts, while others have short, stout ones.   

New research is shedding light on some of these old Ichthyosaur specimens. A study from the University of Bristol shows that Ichthyosaurs may have had different diets.  

“Functional studies need excellent three-dimensional specimens, and the Lower Jurassic ichthyosaur fossils from Strawberry Bank in Ilminster are just that. Mary Anning’s fossils are amazing, but they are mostly squashed flat,” said Matt Williams of Bath Royal Literary and Scientific Institution.

“Our idea was to CT scan the specimens,” said Dr. Ben Moon, of Bristol’s School of Earth Sciences and a supervisor of the study. “The scans allow us to make a detailed, 3D model of the skull in the computer, and it can then be tested for the likely forces experienced during biting.”

“After we had the models, we could stress test them,” said supervisor Andre Rowe. “We tested and confirmed the hypothesis that the slender-snouted ichthyosaur had a quick but weak bite, and the broad-snouted ichthyosaur had a slow but powerful bite.”

“Confirming the supposition was important,” added Professor Michael Benton. “It’s important we apply rigorous scientific approaches such as these engineering analyses. The two species of ichthyosaur presumably chased fast-moving prey (the fast biter) and slower, tough-shelled prey (the slow, powerful biter).”

Professor Benton noted that modern marine predators comparable to Ichthyosaur (like orcas and sharks) eat whatever they can, so it’s interesting that these marine reptiles had specialized feeding habits. “The work can be extended to explore other marine reptiles such as plesiosaurs and crocodiles, so we get a detailed picture of these amazing and alien worlds of the Jurassic oceans.”

The study is published in the Journal of Anatomy

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—

By Zach Fitzner, Earth.com Staff Writer