Most complete set of mastodon remains in Europe found at the Baza fossil site
The ninth excavation campaign confirms this Pliocene site as an international scientific reference
The Baza-1 fossil site (Granada, southern Spain) has once again yielded exceptional discoveries that confirm it as the richest site in Europe in mastodon remains. The recently completed ninth excavation campaign has recovered 240 new fossil specimens, mainly from two species of primitive elephants: Mammut borsoni and Anancus arvernensis, the latter a large mastodon that could reach three metres in height and four-metre-long tusks.
The fieldwork was carried out over three weeks in the Barranco de las Seguidillas–Cuesta del Francés area by a multidisciplinary team of 25 researchers and students. The research is part of the General Research Project on the Pliocene of the Baza Basin, authorised by the Andalusian Regional Government and funded by the Baza City Council. The project is led by Dr Bienvenido Martínez-Navarro, ICREA researcher at the IPHES-CERCA, Dr Antoni Canals, professor at the Universitat Rovira i Virgili and researcher at IPHES-CERCA, and Dr Sergio Ros-Montoya, professor at the University of Málaga.
A 4.5-million-year-old palaeontological treasure
Discovered in 1996, the Baza-1 site dates back around 4.5 million years, corresponding to the Lower Pliocene. In just 55 square metres excavated, researchers have recovered more than 3,250 fossil specimens, an exceptional density that underlines the uniqueness of this site within the European fossil record.
Among the most remarkable findings from this campaign is a mastodon tusk fragment over one metre long, and especially the remains of four Anancus arvernensis individuals of different ages: an old adult, a young adult, a juvenile, and a baby with an almost intact milk tooth.
This age diversity suggests that they may represent a family group of mastodons that became trapped in mud and died together — a possible catastrophic event that researchers will continue to study. “The fact that remains of only this species appear in the same stratigraphic level reinforces this hypothesis,” explain the project leaders.
A window into an ancient tropical refuge
The discoveries at Baza-1 provide not only insights into the Pliocene proboscideans but also into the ecosystem in which they lived. Alongside the mastodons, the team identified remains of three individuals of Mammut borsoni, rhinoceroses, three-toed horses (hipparions), large forest-dwelling bovids (Alephis), antelopes, deer, giant bears (Agriotherium), and even the last known crocodile in Europe.
The site also contains small vertebrates, invertebrates, and abundant plant remains, revealing a rich biodiversity in a warm and humid environment, very different from today’s landscape. “We know that 4.5 million years ago this area acted as a tropical refuge in southern Iberia, with high temperatures and abundant water — essential conditions for crocodiles and other species of African origin,” explains Bienvenido Martínez-Navarro.
Meticulous excavation and long-term research
During this campaign, the work focused on Stratigraphic Unit 5, located about four metres above the richer levels of Stratigraphic Unit 2. To preserve the site’s structure, the excavation was carried out manually, using pick and shovel under strict geological control, without any heavy machinery.
According to Antoni Canals, “our goal is to understand how the sedimentary layers evolved in order to reconstruct, with the greatest precision, the processes that led to the accumulation of fossils. Baza is a true window into the Pliocene — a natural archive that allows us to study the fauna, climate, and ecosystems of that period in extraordinary detail.”
A project with scientific and social impact
In addition to field research, the team promoted public outreach and educational activities to bring palaeontology closer to society. During the campaign, the site received visits from local authorities, schools, and numerous visitors who had the opportunity to learn first-hand about the ongoing scientific work.
“The Baza site is already, without a doubt, a scientific reference at both European and global levels. We hope that in the coming years it can be musealised and become an emblematic Pliocene landmark within the Granada Geopark — accessible and enjoyable for the wider public,” concludes Martínez-Navarro.