The skull was discovered in the 1990s during excavations at Els Casots, a fossil site in Subirats (Alt Penedès) that has become a key Miocene locality in Europe.
Initially, scientists thought the fossil belonged to a known Paludocyon specimen, based on fragmentary remains previously found in the region and elsewhere. Lacking new material to investigate, the skull was placed in storage.
It was not until 2014, while a doctoral student was preparing a thesis, that the skull was re‑examined and researchers noticed discrepancies. The species it had been compared with was far more robust—approximately the size of a lion or tiger and weighing close to 200 kg.
The specimen appeared smaller and less robust than the reference species. The team at the Institut Català de Paleontologia Miquel Crusafont spent the subsequent two years verifying their hypothesis, concluding that the fossil represented a previously undescribed species.
The new species was named Paludocyon moyasolai to honour palaeontologist Salvador Moyà‑Solà, establishing Els Casots as the global reference site for this animal.
The study was conducted in collaboration with the Institut Català de Paleontologia Miquel Crusafont, the Spanish National Museum of Natural Sciences (CSIC), the University of Valencia, the Autonomous University of Barcelona, the Complutense University of Madrid, Ecuador’s National Biodiversity Institute, and South Africa’s Iziko Museums.
A medium‑sized predator in a tropical lagoon
Based on their measurements, the amphicyonid—an extinct carnivore group exhibiting both canine‑ and ursine‑like features—was roughly the size of a large dog, weighing between 50 and 70 kg.
The recovered material comprised the skull, most of the dentition, and an isolated lower molar. This assemblage allowed the team to notice a distinctive dental pattern: an unusually broad second upper molar and a third molar larger than typical for the genus.
These dental characteristics indicate a varied diet, suggesting a mesocarnivorous predator that could hunt small to medium‑sized prey—such as primitive deer, bovids, and ancestral pigs—without possessing the sheer power of the dominant predators in its ecosystem. The site also produced a second, considerably larger amphicyonid, roughly the size of a leopard, which remains undescribed.
Approximately 15.9 million years ago, the environment was a shallow lagoon encircled by tropical forest, inhabited by crocodiles, snakes, fish, and a rich assemblage of mammals.
The leaders of the excavation note that this aquatic setting ensured excellent fossil preservation; postmortem burial in mud shielded the remains from decay.
Another piece in the map of Miocene carnivores
The find contributes to ongoing research on Miocene carnivore community structure in the Iberian Peninsula. Earlier work from the Complutense University of Madrid examined slightly younger sites—Los Valles de Fuentidueña (Segovia) and Cerro de los Batallones (Madrid)—where an exceptionally diverse array of carnivores, including bear‑dogs, felids, hyaenas, and bears, co‑existed.
Stable‑isotope analysis of over 200 tooth‑enamel samples, reported in a Palaeontology paper, revealed intense competition among these carnivores, except for species such as the amphicyonid in question and a primitive hyaena, which preyed on different animals in more open habitats.
Isotopic studies enable highly precise dietary reconstruction with minimal damage to fossils; only a few milligrams of enamel need to be extracted with a dental drill and then analyzed by mass spectrometry.
When applied across multiple Miocene sites and time intervals, this methodology is producing a nuanced understanding of how faunal communities responded to environmental shifts—from dense forests to open, arid habitats—and which ecological strategies permitted species coexistence amid fierce competition.
Paludocyon moyasolai represents another element of this broader puzzle, occurring slightly earlier than the assemblages studied at Fuentidueña and Batallones but still within the amphicyonid lineage that dominated Eurasia and North America throughout the Cenozoic. Each newly described specimen, researchers note, refines the group’s evolutionary tree and enhances our understanding of its ultimate extinction a few million years later.
