To gauge the value of the paleontological heritage of La Rioja (a small region in northern Spain better known internationally for its wines) it is necessary to travel back 120 to 130 million years. From that time, the Early Cretaceous — of which more than 170 sites and over 11,000 dinosaur footprints remain —experts have reconstructed an ecosystem dominated by a vast lake on a broad alluvial plain that was about 400 square kilometers (154 square miles) and where rivers emptied into the area. At that time, the Iberian Peninsula was a large island near the Canary Islands, with a humid subtropical to tropical climate that produced lush vegetation, including conifers and tree ferns, and supported large dinosaurs.
“The kings were undoubtedly the spinosaurids, which had specialized in fishing —they were skillful fishers— but they were also capable of hunting smaller dinosaurs,” says Francisco Sáez-Benito, honorary director of the La Rioja Paleontological Center. Alongside these large predators there were herbivores, ornithopods and even sauropods that took advantage of the abundant food in the area. Other animals completed the ecosystem, including large fish, crocodiles, lizards and turtles. When the lake’s water level fell, it exposed broad plains whose mud preserved the footprints and remains of these animals down to the present day.
The latest find from the recent paleontological campaign at the Las Cerradas site, in the small village of Igea, are new fossil remains that may belong to a previously unknown large herbivorous dinosaur species. Specifically, the discovery includes elements related to the pelvic girdle, a scapula and several hand bones, including metacarpals and phalanges. These pieces, combined with those recovered in the 2025 campaign —several hind-limb elements and new caudal vertebrae— “will allow the reconstruction of more than half the animal’s tail, which is spectacular,” said Sáez-Benito, co-director of the Garras excavation team and director of the digs alongside researchers from the Universities of La Rioja, the Basque Country and A Coruña. “With these bones we are going to put a name and surname to this animal,” the paleontologist added, expressing confidence that after further study and final restoration of the fossils they will be able to determine “its genus and species.”
However, the path to that goal still includes several intermediate steps. The first is to continue excavations at the same site in 2027 to recover more remains and complete the skeleton. Each of these pieces must then undergo a meticulous restoration process at the Igea Paleontological Center. From that point the anatomical and systematic study of the collection can begin. “The research could extend for several years,” the head of the center in La Rioja explains. “A new species that will help underscore La Rioja’s immense paleontological heritage,” he adds.
In 2024 the carnivorous dinosaur Riojavenatrix lacustris was described —a large predator measuring between seven and eight meters long and weighing about 1.5 tons. Earlier, the most complete spinosaurid skeleton yet found was also recovered; that specimen was named Villar. Discoveries in this part of La Rioja include the remains of a small ornithopod dinosaur found in 1985 and a new species of freshwater turtle discovered in 2012.
The excavation has also recovered fossils of other organisms that shared the ecosystem. Finds include crocodiles, lepisosteiform fishes, coprolites (fossilized feces) attributed to hybodontids —a group of primitive freshwater sharks— as well as plant remains. “We have identified up to six different shark species and three or four crocodile species,” Sáez-Benito says.
“We will be able to reconstruct with greater precision and detail the environment in which the dinosaurs lived,” Sáez-Benito says, referring to a setting where large herbivores, aquatic reptiles, fish, turtles and abundant shoreline vegetation coexisted around the great lake and its rivers.
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