Paleontologists Uncover Fossil of New Species of Ancient Dolphin-like Reptile

First Posted: May 15, 2013 11:01 AM EDT

During the age of the dinosaurs, a dolphin-like marine reptile once travelled the ancient seas that once covered the Kurdistan region of Iraq. Known as an ichthyosaur, the reptile was once thought to have declined gradually in diversity. Now, though, paleontologists have unearthed the remains of a creature that has completely altered this view.

Ichthyosaurs are well established in the fossil record. There are hundreds of examples of their remains from the time of the dinosaurs. Ranging in size from less than three feet to over 65 feet in length, these creatures gave birth to live young at sea. Some of them were fast-swimming, deep-diving animals with enormous eyeballs and a warm-bodied physiology.

The newly discovered ichthyosaur is named Malawania anachronus, which means "out of time swimmer." It probably lived during the Cretaceous period, which is unusual. The reptile represents a kind of ichthyosaur that researchers have long believed went extinct during the Early Jurassic, more than 66 million years earlier. In fact, the remains seem to show that the archaic ichthyosaur experienced an evolutionary stasis: it doesn't seem to have changed much at all between the Early Jurassic and the Cretaceous.

"Malawania's discovery is similar to that of the coelacanth in the 1930s: it represents an animal that seems 'out of time' for its age," said Valentin Fischer of the University of Liege in Belgium, in a news release. "This 'living fossil' of its time demonstrates the existence of a lineage that we had never even imagined. Maybe the existence of such Jurassic-style ichthyosaurs in the Cretaceous has been missed because they always lived in the Middle-East, a region that has previously yielded only a single, very fragmentary ichthyosaur fossil."

After discovering this new ichthyosaur, the researchers decided to take things one step further. They examined microscopic spores and pollen that were preserved in the same slab as the ancient remains of the reptile and then analyzed the ichthyosaur family tree. Building off of their findings, the researchers were able to retrace the evolutionary history of the Cretaceous ichthyosaurs. In fact, they were able to show that numerous ichthyosaur groups that appeared during the Triassic and Jurassic survived into the Cretaceous.

The findings reveal that the supposed end of Jurassic extinction event did not actually occur for ichthyosaurs. This makes their fossil record distinct from other marine reptile groups. The research allows us to learn a little bit more about our Earth's ancient past, and shows us a little bit more about the ancient creatures that once inhabited it.

The findings are published in the journal Biology Letters.

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