Paleontologists on the Spanish island of Tenerife have unearthed an extraordinarily well-preserved, articulated skeleton of a lizard estimated to be around 700,000 years old. This significant find is believed to potentially represent an example of Gallotia goliath, an extinct giant lizard species that existed long before humans arrived in the Canary Islands.

A 700,000-year-old articulated lizard’s skeleton was discovered on the Spanish island of Tenerife. Credit: Emeterio Suárez/University of La Laguna

The discovery was made by retired botanist Arnoldo Santos-Guerra, who stumbled upon the fossil two years ago while searching for snail shells. He found the specimen embedded in a 42-pound sandstone block. Remarkably, this block also contained remains of a second lizard, although this smaller or juvenile specimen was not as well preserved.

Recognizing the importance of his find, Santos-Guerra contacted Carolina Castillo Ruiz, a paleontologist at the University of La Laguna. Under her guidance, the fossil was scanned and cleaned, and it is now housed in the Biology Section of the university, awaiting further study.

“The main lizard retains its morphology entirely, allowing a clear view of its skeletal structure,” said Castillo Ruiz. The excellent state of preservation suggests the lizard died and was buried suddenly, possibly due to an accidental or sudden event, which protected it from decay and scavengers. The hypothesis is that both lizards might have been trapped in a sand dune formation, leading to their remarkable preservation.

Initial analyses indicate similarities between the fossil and Gallotia species from El Hierro, another island in the Canary Archipelago. However, the precise species identification requires detailed study. Computed tomography (CT) scans of the head, separated from the body, have been conducted to create a 3D model for comparison with both extinct and extant species.

“Thanks to the good state of conservation of the piece, it is possible to determine the exact proportions of the animal without resorting to the traditional regression line,” Castillo Ruiz explained. This makes the comparisons more accurate and reliable. A detailed bone-by-bone analysis will be conducted to uncover subtle anatomical features.

The preservation of the skeleton allows scientists to study the morphology and potential behaviors of these ancient reptiles, contributing to broader research on biodiversity and environmental changes in the Canary Islands.

The laboratory at the University of La Laguna, where the specimen is kept, is a treasure trove of paleontological heritage. It holds thousands of fossil collections, including remains of plants, vertebrates, invertebrates, and trace fossils from both terrestrial and marine environments. Among these are lizard remains from El Hierro, dated between 4,000 and 15,000 years old, which include well-preserved jaws with teeth, leg bones, and other cataloged elements. This extensive collection provides a rich resource for comparative studies.

Future research will focus on a thorough examination of the fossil’s anatomical features, contributing to a deeper understanding of the biodiversity and environmental shifts that have occurred over millennia in the Canary Islands.

University of La Laguna