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First dinosaur fossil discovered in Spain much newer than thought

Unearthed in 1987, Aragosaurus ischiaticus, roamed what is now Spain some 130 million years ago. Using fossilized pollen, paleontologists have calculated that it lived about 15 million years later than previously thought. 

The first dinosaur ever found in Spain is not as old as paleontologists had believed — though at 130 million years old, the long-necked creature is no spring chicken.

The dinosaur,ÌýAragosaurus ischiaticus, was originally discovered in 1987. ButÌýÌýwas difficult to date. Now, researchers at the University of Zaragoza's Aragon Research Institute of Environmental Sciences have found the sauropod's age was estimated at 15 million years too old. The age-shaving results suggest the dinosaur was an ancestor of the enormous Titanosauriforms, a group that includes theÌýÌýto ever live.

The new age estimate puts the dinosaur in the Hauterivian age between 136 million and 130 million years ago, the researchers reported March 12 in the journal Geological Magazine.

"This is the only dinosaur of this period found in Spain and is also the most intact in Europe," study author José Ignacio Canudo of the University of Zaragoza said in a statement. "It can be categorized amongst the well-known sauropods of the Jurassic-Cretaceous transition (135 million years ago), the most abundant species during the Barremian age (116 million years ago). As this group has been studied the least, theÌýAragosaurusÌýfills the gap."

To accurately date theÌýAragosaurusÌýspecimen, Canudo and his colleagues conducted fieldwork at the site of the find. They used fossil pollen found in the same layers of sediment as theÌý´¡°ù²¹²µ´Ç²õ²¹³Ü°ù³Ü²õÌýto pinpoint the date. By knowing the evolutionary history andÌýÌýthat released that pollen, the researchers can estimate the ages of fossils found in the same layers.

The more accurate date helps flesh out the sauropod family tree, the researchers reported.Ìý´¡°ù²¹²µ´Ç²õ²¹³Ü°ù³Ü²õÌýfills a gap in fossil knowledge during the shift from the Jurassic to the Cretaceous period, Canudo said.

You can followÌýÌýsenior writer Stephanie Pappas on TwitterÌý.ÌýFollow LiveScience for the latest in science news and discoveries on TwitterÌýÌýand onÌý.