An 82-foot dinosaur turned up in Spain after only ever being found in America

Paleontologists working at the La Tejería site in El Castellar, in the Spanish province of Teruel, have identified 14 tail vertebrae and a handful of chevron bones as belonging to Diplodocus, the whip-tailed sauropod that stretched roughly 82 feet, or about 25 meters, from nose to tail. Until this month, every confirmed Diplodocus specimen on record had come out of the Morrison Formation in the western United States. The Teruel find, described in a new paper from researchers at the Fundación Conjunto Paleontológico de Teruel-Dinópolis, is the first evidence that the genus lived anywhere else.

The rock layer that held the bones dates to roughly 150 million years ago, near the close of the Jurassic Period. Lead author Sergio Sánchez Fenollosa said the identification came together slowly rather than all at once. “It was an exciting and continuous process of seeing the pieces of the puzzle gradually fall into place,” he said, describing how early similarities to other diplodocine sauropods hardened into a firm match once the team ran deeper anatomical and evolutionary analysis.

Four features in the tail bones sealed the identification

The specimen carries large pneumatic cavities inside the vertebrae, deep longitudinal grooves running along the underside of the tail bones, distinctively forked chevron bones with their own medial fossae, and elongated vertebral centra without lateral ridges — a combination the Teruel-Dinópolis team says is diagnostic of the genus and not shared with other diplodocids known from Iberia. Using both bone-by-bone comparison and phylogenetic methods that included maximum parsimony and Bayesian inference, the researchers placed the fossil as a close relative of Diplodocus hallorum, a species previously known only from New Mexico.

Co-author Alberto Cobos, managing director of Fundación Dinópolis, said the animal measured approximately 25 meters, comparable in size to its North American relatives, and that it joins other giant sauropods already known from Teruel, including Turiasaurus and Losillasaurus — dinosaurs built on a very different body plan from a diplodocid’s. Cobos said the accumulation of finds is what makes the province, in his words, “a reference place for understanding this great diversity.”

A narrower Atlantic left room for a land bridge

The Spanish Diplodocus lived near the end of the Jurassic, when the proto-North Atlantic Ocean was far narrower than today’s and periodically shrank further during regressive phases that geologists believe could have exposed temporary land connections between Iberia and eastern North America. Sánchez Fenollosa called the specimen “some of the strongest paleontological evidence for episodes of dispersal and faunal exchange between the two continents across the proto-Atlantic Ocean during the Late Jurassic,” adding that the find helps clarify the diversity of sauropods that inhabited the European Jurassic.

Outside researchers see the same pattern building over several years of related discoveries. Francisco Ortega, a paleontology professor at Spain’s UNED who was not involved in the study, noted that Teruel’s Jurassic rock has already produced Iberian relatives of Allosaurus and Stegosaurus, both icons of the Morrison Formation, and said Diplodocus now completes what he called the region’s “complete set of dinosaur trading cards” shared with North America.

Other specialists want more bone before calling it settled

Not every scientist who reviewed the paper is convinced the genus-level call will hold up. José Ignacio Canudo, a paleontology professor at the University of Zaragoza, said the remains are informative but thin, arguing that a section of tail consisting solely of caudal vertebrae is too fragmentary, in his view, to pin down to the genus Diplodocus with certainty. He nonetheless agreed the broader case for a transatlantic dinosaur connection stands regardless of exactly which label the specimen ends up wearing.

Fabien Knoll, a researcher in the department of paleobiology at Spain’s National Museum of Natural Sciences, offered a similar caveat: the material is “compatible” with Diplodocus but does not yet rule out a close relative such as Supersaurus or Dinheirosaurus. He said further fieldwork in Spain and Portugal, plus formal publication of fossils already sitting in collections, would help settle which genus the El Castellar bones actually belong to.

The bones are now on public display at Dinópolis

The fossils have been moved into the dinosaur hall of the Museo Aragonés de Paleontología at Dinópolis in Teruel, a city roughly midway between Madrid and Valencia, where they are available for both continued research and public viewing. The surrounding rock has already produced sauropods, theropods, stegosaurs and ornithopods, evidence the paper’s authors say points to a complex coastal ecosystem along the Late Jurassic Iberian shoreline rather than an isolated pocket of unusual fauna. The full description, “Intercontinental evidence of the iconic genus Diplodocus,” ran in the Journal of Vertebrate Paleontology and lists Sánchez Fenollosa, Josué García-Cobeña and Cobos as authors.

Diplodocus has been a museum fixture since its first description in the United States in 1878, with plaster casts of its skeleton shipped to natural history halls around the world through the early 20th century — the long neck, whip tail and small head turning it into shorthand for “dinosaur” in classrooms long before most visitors could name a second sauropod. That familiarity is part of why paleontologists on both sides of the review process called the find significant even while disagreeing on the label: a genus this recognizable had simply never been documented anywhere but a single formation in the American West.

Whether the Teruel specimen ultimately keeps the Diplodocus name or is reclassified as a close cousin such as Supersaurus once more caudal vertebrae turn up, the paper marks the first time bones from this body plan have been pulled out of European rock and formally compared against the Wyoming, Colorado and Utah quarries that have defined the genus for nearly 150 years. Canudo’s caution and Knoll’s request for more fieldwork both point the same direction: the next test of the Teruel Diplodocus will come from more bone, not more analysis of the bone already in hand.

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This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.