Metapodial bones of Ursus gr. spelaeus from selected caves of the North Italy. A biometrical study and evolutionary trend.

The cave bear evolution is characterized by some specific trends, including the increase in size, the progressive complication of the tooth surface and the gradual strengthening of the metapodial bones. Important indicators of the evolutionary level are the morphodynamic index of P4/4 and the plumpness index of the metapodial bones. Only recently, the morphological and morphometric analysis was complemented by genetic analysis – particularly of mtDNA. As a consequence, mainly based on genetics, new taxa have been proposed, for some of whom the exact taxonomic rank (species or subspecies?) is still under discussion. However, the new evolutionary model presents some problems because the genetic data alone are not sufficient to ensure a specific distinction and the morphodynamic and morphometric data do not support a specific distinction between the cave bear populations. The morphometric analysis performed on numerous metapodial bones belonging to some Italian (Buco dell’Orso, Covoli Velo and S. Donà di Lamon) and European populations seems to confirm, on the whole, a level of diversity not higher than that of a subspecies, allowing at most the identification of some local evolutionary trends, as assumed for the populations which have been living in the Italian peninsula.