New mtDNA and Isotopic Evidence on Late Pleistocene Cave Bears in the Balkans: the Case-study of Magura Cave, NW Bulgaria

Recent genetic studies have shed light on the phylogeography of cave bears; however, their paleoecology and their diet are still debated, and data from south-eastern Europe are still scarce. Magura Cave, in northwest Bulgaria, has delivered rich faunal assemblages from the Late Pleistocene. The chronology of the excavated area spans from ca. 35 kya to more than 50 kya; the oldest stratigraphic layers being associated with final Middle Palaeolithic tools. The fauna comprises herbivores and carnivores, and potentially different taxa of cave bears, the dental remains of which also showed different tooth morphotypes, suggesting the co-existence of different dietary adaptations. We investigated the mitochondrial DNA (mtDNA) lineages of the cave bears from Magura Cave as well as the stable carbon and nitrogen isotope composition of the faunal assemblage. Our data revealed that, regardless of the tooth morphotypes, only maternal lineages of Ursus ingressus were present in Magura Cave. Interestingly, one specimen with Ursus arctos mtDNA was also found, showing a clear carnivore diet. In contrast, the U. ingressus specimens had a predominantly herbivorous diet. The tooth morphotypes were associated with significantly different δ13C values, suggesting different dietary adaptations.

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