The mandible of Salbatore II: A new Ursus deningeri site in the northern Iberian Peninsula

Ursus deningeri, together with Ursus spelaeus sensu lato, are chronospecies that belong to the Quaternary iconic cave bear lineage. They inhabited Iberia from the late Early to the late Middle Pleistocene. Here we describe a complete bear mandible recovered from Salbatore II cave (Basque Country). To assess its taxonomy, we compared it with other European Pleistocene cave and brown bears. Comparisons were made concerning its morphology and using both traditional and 3D geometric morphometrics analyses. The mandible has several morphological similarities with the cave bears such as a high corpus and deep masseter fossa. However, it exhibits a coronoid process that leans backwards, a pointed pterygoid process, and the p1 and p3 are present. These are characteristics customarily associated with U. deningeri and U. arctos. Metric analyses show that Salbatore II fits within the cave bear variation, with a minimum overlap with brown bears once size is accounted for. However, geometric morphometric analyses show that Salbatore II is similar to U. arctos, but within U. deningeri variation. Based on the overall size and the morphological characteristics, Salbatore II displays U. deningeri affinities with many ancestral characteristics, suggesting a minimum mid-Middle Pleistocene age, a chronology rarely recorded in the Cantabrian region.