A 25-Meter Diplodocus Has Turned Up in Spain. It Is the First Confirmed Specimen Ever Found Outside North America, and It Means Sauropods Walked Across a Land Bridge to Europe 150 Million Years Ago.

For more than a century, Diplodocus has been an American dinosaur. The whip-tailed giant that anchors the great halls of natural history museums from Pittsburgh to London was known only from the Morrison Formation of the western United States, and every cast of "Dippy" shipped abroad was a copy of a North American skeleton. That is no longer true. Paleontologists in Spain have identified a Diplodocus from a site in the province of Teruel, the first confirmed specimen of the genus found anywhere outside North America, according to a study published this month in the Journal of Vertebrate Paleontology.

The fossils come from La Tejería, a Late Jurassic locality near the village of El Castellar, and consist of 14 tail vertebrae and several chevrons, the V-shaped bones that hang beneath a sauropod's tail, all belonging to a single individual. The team from the Fundación Conjunto Paleontológico de Teruel-Dinópolis, led by doctoral student Sergio Sánchez Fenollosa, estimates the animal was roughly 25 meters, or about 82 feet, long, on par with its North American relatives. The rocks date to approximately 150 million years ago.

What makes the identification secure is the detail preserved in the tail. The vertebrae carry large pneumatic cavities, the air-filled hollows that lightened sauropod skeletons, along with deep longitudinal grooves, forked chevrons with distinctive medial fossae and elongated vertebral centra lacking lateral ridges. Those are the features that separate Diplodocus from its close cousins Apatosaurus and Barosaurus, and phylogenetic analyses placed the Spanish animal as a close relative of Diplodocus hallorum, the species formerly known as Seismosaurus. Diplodocid sauropods had been reported from Portugal and elsewhere in Europe before, but none could be confidently assigned to Diplodocus itself.

The biogeographic implications are the point. In the Late Jurassic, the Atlantic was a young, narrow ocean, and sea levels rose and fell enough that temporary land bridges connected what is now eastern North America to Iberia during low stands. A Diplodocus in Spain "provides compelling evidence that dinosaurs could migrate between North America and Europe during the Late Jurassic," the authors write, most likely during those regressive phases of the proto-Atlantic. The Morrison and Iberian faunas had long looked suspiciously similar, with shared genera such as Allosaurus and Stegosaurus; a shared Diplodocus closes the argument.

Teruel has become one of Europe's most productive dinosaur regions over the past two decades, producing the giant Turiasaurus in 2006 and a string of sauropod, stegosaur and theropod finds since. The Dinópolis foundation excavated La Tejería over several field seasons, and the Diplodocus bones are now on display at the Museo Aragonés de Paleontología in Teruel.

For the animal itself, the crossing would have been unremarkable. Diplodocus was a low browser with peg-like teeth and a tail that may have cracked like a whip, moving in herds across floodplains. That one of those herds walked from Wyoming to Aragón, or that its ancestors did, changes how paleontologists reconstruct the Jurassic world: not as isolated continents with their own giants, but as a connected landscape where the largest animals that ever walked could, when the sea pulled back, simply keep going.