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The mandible size variability including sexual size dimorphism (SSD) of the cave lion (Panthera spelaea) in the Pleistocene of Northern Eurasia time has been studied basing on the univariate and multivariate statistical analyses of 76 specimens from 43 localities. It has been confirmed that SSD in adult P. spelaea, as well as in extant P. leo, is the dominant form of group variability of mandible and, to somewhat lesser extent, of variability of cheek teeth. The lowest degree of SSD has been found in a relatively small Beringian subspecies, P. spelaea vereshchagini. The geographical variability of the cave lion from Western to Eastern Eurasia was not a cline at least in the Late Pleistocene. Our results confirm a decrease in overall mandible size from the Middle Pleistocene to the Late Pleistocene over a large part of the species' range. We speculate that evolutionary changes in mandible size, lower canines or cheek teeth may have proceeded at different rates, allometry and probable heterochrony. Our results have added a new evidence to support the subspecies status of the Beringian lion (P. spelaea vereshchagini), but they are insufficient for other decisions on cave lion taxonomy at the subspecies level. [ABSTRACT FROM AUTHOR]

Extinct cave bears inhabited a large part of Eurasia in a wide diversity of habitats during the Pleistocene. This study investigates via tooth wear analysis the feeding habits of 66 individuals belonging to three genetically different species located in the Urals and eastern Europe: Ursus rossicus from Kizel cave, U. kanivetz from Secrets cave, and U. ingressus from Shiriaevo 1 cave. For the microwear analysis, the three species were compared with a reference collection of extant ursids. The dietary space of U. kanivetz does not match any of the extant species' spaces. U. rossicus and U. ingressus tended towards some of the extant species' measurements without any overlapping. For all three sites, the same microwear pattern was identified for all age groups (juvenile, prime, and old adult), meaning no differences related to ontogeny were found. The extinct species presented a larger number of coarse scratches compared to extant species, pointing to a preference for abrasive food items like dry grass or shrubs typical of the mammoth steppe biome during the cold season. These results indicate a niche partitioning between U. rossicus and U. kanivetz that co-existed in the same area, and in this way they avoiding competition. [ABSTRACT FROM AUTHOR]

The Bering Land Bridge (BLB) last connected Eurasia and North America during the Late Pleistocene. Although the BLB would have enabled transfers of terrestrial biota in both directions, it also acted as an ecological filter whose permeability varied considerably over time. Here we explore the possible impacts of this ecological corridor on genetic diversity within, and connectivity among, populations of a once wide‐ranging group, the caballine horses (Equus spp.). Using a panel of 187 mitochondrial and eight nuclear genomes recovered from present‐day and extinct caballine horses sampled across the Holarctic, we found that Eurasian horse populations initially diverged from those in North America, their ancestral continent, around 1.0–0.8 million years ago. Subsequent to this split our mitochondrial DNA analysis identified two bidirectional long‐range dispersals across the BLB ~875–625 and ~200–50 thousand years ago, during the Middle and Late Pleistocene. Whole genome analysis indicated low levels of gene flow between North American and Eurasian horse populations, which probably occurred as a result of these inferred dispersals. Nonetheless, mitochondrial and nuclear diversity of caballine horse populations retained strong phylogeographical structuring. Our results suggest that barriers to gene flow, currently unidentified but possibly related to habitat distribution across Beringia or ongoing evolutionary divergence, played an important role in shaping the early genetic history of caballine horses, including the ancestors of living horses within Equus ferus. [ABSTRACT FROM AUTHOR]