A previously undocumented species within the extinct carnivorous mammal family Amphicyonidae, colloquially termed “bear-dogs,” has been identified by paleontologists. This discovery stems from two fossil specimens excavated at a prolific paleontological site situated in the Vallès-Penedès Basin, proximate to Barcelona, Spain.
Paludocyon moyasolai. Image credit: Jesús Gamarra.
Designated Paludocyon moyasolai, this newly identified species roamed the Earth during the Middle Miocene epoch, approximately 15.9 million years ago. At that time, the region was characterized by a warm climate, extensive forestation, and numerous shallow water bodies.
This ancient creature belonged to the Amphicyonidae family, a now-extinct lineage of predators colloquially referred to as bear-dogs due to their amalgamation of morphological traits found in both modern bears and canids, despite not being directly ancestral to either.
“The Amphicyonidae constituted a significant component of carnivoran fauna across North America and Eurasia for a substantial duration of the Cenozoic Era,” stated Dr. Jorge Morales of the National Museum of Natural Sciences-CSIC, alongside his research associates.
“In Africa, evidence of amphicyonids first emerges in the Early Miocene, with their presence extending to the close of the Late Miocene, representing the latest known occurrences of this group on the continent.”
“Recent scholarly discourse has posited a North American origin for this family. This hypothesis is bolstered by the more comprehensive and varied Paleogene fossil record of amphicyonids documented in North America when contrasted with that of Western Europe and Asia.”
The researchers recovered two specimens of Paludocyon moyasolai from the els Casots excavation site within the Vallès-Penedès Basin, Spain.
The fossil assemblage comprises a flattened yet remarkably preserved partial cranium, retaining most of its dentition, in addition to a solitary lower molar found separately.
Both recovered specimens are currently curated at the Miquel Crusafont Institute of Paleontology in Sabadell, Spain.
According to the research team, Paludocyon moyasolai can be differentiated from its closest phylogenetic relatives by the distinctive proportions observed in its molar teeth.
Specifically, its second upper molar exhibits a greater width than the first upper molar, while its third upper molar is notably large and highly developed.
These particular dental characteristics have heretofore not been documented in other known members of the Paludocyon genus.
To ascertain the precise placement of Paludocyon moyasolai within the evolutionary tree, Dr. Morales and his co-authors engaged in comparative analyses of its dentition against that of related species from both European and North American fossil sites.
Their findings indicate that this newly identified species represents the most ancient lineage within the Paludocyon genus, thereby classifying it among the most primitive extant members of this group.
Furthermore, the study provides support for the proposition that the long-established genus Cynelos may not represent a monophyletic grouping—in technical terms, it is paraphyletic, implying that not all its constituent members share a singular, exclusive common ancestor.
Three species currently classified under Cynelos and originating from North America present a particular taxonomic challenge.
The phylogenetic analysis positions these North American species more closely related to Paludocyon than to their European counterparts within Cynelos, yet their definitive classification remains an open question.
The scientific team speculates that these North American fauna might have undergone independent evolutionary trajectories from their European contemporaries, potentially evolving from Asian ancestors or from endemic North American lineages.
“The phylogenetic analysis suggests that Cynelos is paraphyletic, while concurrently supporting the monophyly of Paludocyon, with the newly discovered species representing its most basal member,” the authors noted.
“This finding corroborates a distant evolutionary connection between the Cynelos species from Europe (specifically Cynelos rugosidens and Cynelos lemanensis) and the Paludocyon clade, justifying their designation as distinct genera.”
This significant paleontological discovery has been formally documented in a scientific publication featured in the Journal of Mammalian Evolution.
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J. Morales et al. 2026. A new species of Paludocyon (Carnivora: Amphicyonidae) from the early Middle Miocene of els Casots (Vallès-Penedès Basin, Barcelona, Spain). J. Mamm. Evol 33, 29; doi: 10.1007/s10914-026-09814-6
