Lo Hueco site

A discovery during construction

In May 2007, during archaeological monitoring of the AVE high-speed railway works towards Levante, dinosaur bones emerged as a small hill between Arcas del Villar and Fuentes was cut down. Nothing comparable is known in the surrounding area.

What it was

It dates from the end of the Cretaceous, the dinosaurs’ last few million years. Rivers and waterlogged areas then occupied the site, leaving grey, brown, red and green marls and mudstones. These yielded several dinosaurs, crocodiles and turtles, footprints, fish, amphibians, reptiles and ferns, in exceptional density and variety. It is one of the most important fossil vertebrate discoveries in Spain and Europe: more than 8,500 large fossils, including theropods, ornithopods and titanosaurs. Other counts refer to more than 14,000 remains collected in six months of excavation.

What remains

The site extended around 200 metres in length and 10 in height, at around 1,050 metres above sea level. It was fully excavated and removed: nothing remains to see on the ground.

The excavation continuing in a warehouse

Because the fossils had to be removed quickly during construction, many were extracted in blocks of rock still unopened in 2022. Francisco Ortega, of the UNED, called this work indoor excavation: it takes place in the Cuenca warehouse where the museum stores the collection, while other remains are prepared in laboratories at the Universidad Complutense and the UNED in Las Rozas. That year, with a grant of just over twenty thousand euros from the regional government of Castilla-La Mancha, they were comparing Lo Hueco with Poyos, in Guadalajara, where there is a nesting area with many dinosaur eggs. Both lie in the same formation, Villalba de la Sierra, from the late Cretaceous, but researchers suspected they were not from the same time and wanted to test this using remains of sauropods and large carnivores from both sites. Lo Hueco has also yielded turtle shells with marks interpreted as being from leeches, and bones bearing insect traces, helping establish how the carcasses decomposed.

Plan your visit

To learn about it, go to the exhibition centre in Fuentes, on the Cuenca Dinosaur Route, and the replica of the titanosaur Epi.

Before you travel

Collecting fossils is permitted only for research.

Combine with

Another site in the province, much older, is Las Hoyas; fossils from both can be seen at Cuenca’s Museo de Paleontología.