Researchers have identified a newly discovered freshwater mosasaur species named Garamaudo bauciensis, which swam in a tropical lake near Aix-en-Provence 85 million years ago. Paleontologists announced the formal description on September 28, 2026, revealing a creature with limb bones instead of flippers that hunted in what is now Bouc-Bel-Air.
Fossil Discovery in Bouc-Bel-Air
Long before Provence took on its modern, arid landscape, the southern region supported a humid tropical ecosystem characterized by lakes, marshes, and dense vegetation. Within this ancient setting lived a small aquatic reptile whose remains lay preserved in continental deposits at the Bouc-Bel-Air Sousquières site, situated along a regional road in the Bouches-du-Rhône department. Three distinct excavation campaigns—conducted in 1997, 2018, and 2025—unearthed the fragmented jawbones, vertebrae, ribs, a pelvis, and an humerus that eventually allowed researchers to piece together the animal’s anatomy.
While popular discussion often applies the term dinosaur to prehistoric discoveries, this animal belongs to the mosasaures, a group of squamate reptiles traditionally understood as marine predators. The remains from the basin of Aix-en-Provence display an exceptional bone compactness that likely helped the animal stay submerged in shallow water. Analysis of the internal structure, morphology, and cranial fragments enabled scientists to establish that the fossils represent an entirely new species.
Anatomy of a Freshwater Mosasaur
Marine mosasaur species typically grew to immense proportions—some reaching up to 15 meters—with limbs fully transformed into powerful swimming paddles and tails adapted for open-ocean hunting. The specimen found near Aix-en-Provence presents a starkly different physical blueprint. Reaching roughly 2.5 meters in length, the species Garamaudo bauciensis retained functional limb bones with distinct digits rather than webbed flippers, while its pelvis remained fused to the spinal column in a manner reminiscent of terrestrial lizards.
Rather than cutting through ocean currents with rigid flippers, the creature propelled itself through freshwater bodies by undulating its elongated body like an eel, supported by a long tail and straight ribs. Experts describe its living appearance as closer to an elongated giant monitor lizard than to its oceanic relatives. This morphology places the animal within the Tethysaurinae, noted as the sole mosasaurid subfamily known to have evolved freshwater forms.
Multidisciplinary Team Publishes Scientific Description
The formal scientific description was published on September 28, 2026, in the Peer Community Journal by a multidisciplinary team of researchers. Nathalie Bardet and her colleagues at the CNRS led the investigation alongside Thierry Tortosa, conservator at the Sainte-Victoire Nature Reserve. The analysis also incorporated contributions from François-Louis Pelissier of the Var departmental museum.
The recovery of freshwater mollusks within the same geological layers confirms that the habitat was entirely non-saline. Researchers interpret the environment as a moderately eutrophic, carbonate-producing lake influenced by seasonal flooding and dry spells.
The Provençal Roots of Garamaudo bauciensis
The species designation draws directly from regional linguistics and folklore. The genus name combines Garamaudo
, a reference to provençal traditions regarding serpent-like freshwater monsters, with the Latin species descriptor bauciensis
in honor of Bouc-Bel-Air. Jean-Marc Perrin, departmental councillor for paleontology, noted that the designation highlights Provence and its cultural traditions on an international stage.
This discovery joins a growing body of evidence showing that freshwater mosasaurs were not entirely isolated anomalies. Prior finds in Hungary, alongside similar material recovered in Portugal, demonstrate that certain mosasaurid groups successfully adapted to continental waterways during the Santonian and Campanian stages of the Cretaceous period.
Department of Bouches-Du-Rhône Plans 2027 Exhibition
The investigation into the ancient aquatic ecosystem of Provence remains active. Additional rock blocks recovered from the Sousquières deposit still await laboratory preparation and analysis, raising expectations for further insights into the animal’s biology. Meanwhile, the Department of Bouches-du-Rhône plans to feature the fossils in a major public exhibition scheduled for 2027, offering visitors a detailed look at the reptiles that inhabited the region’s prehistoric lakes.