Faunal renewals during the Early Pleistocene on the northern Italian Peninsula: Climate and environment reconstructions inferred from the Rivoli Veronese small mammal assemblage (Adige River valley, Verona, Italy)

摘要

The Early Pleistocene is an epoch where wide environmental changes, driven by climate instabilities, were registered by multiple lines of evidence in different chronostratigraphic records, both continental and marine. Among these records, small mammals are one of the most reliable for understanding how faunal assemblages responded to the climate shifts. One of the key regions for this epoch in the European framework is the northeastern Italian Peninsula, which was long considered as an ecotonal zone and crossroad between Central and Mediterranean Europe. In this region, Rivoli Veronese (Verona, north-eastern Italy), an Early Pleistocene site with a highly diversified assemblage, has always been considered one of the most important sites for the biochronology of the Italian Peninsula. Here we present the taxonomic study of the Early Pleistocene insectivores, bats, and rodents from this site, as well as the environmental and climatic reconstruction using the Taxonomical Habitat Index, the Habitat Weighting, and the Bioclimatic model. In the rich Rivoli Veronese assemblage, composed of 27 taxa, important biochronology markers, such as Mimomys pitymyoides, Mimomys tornensis, and Mimomys pliocaenicus were recognized. The earliest occurrences in Europe of Sorex praealpinus and Dinaromys genus were also documented as well as a new fossil mole species, Talpa sp. nov. Comparison with other European small mammal assemblages of the Early Pleistocene have allowed us to relate Rivoli Veronese to the early Late Villanyian Age. The persistence of Pliocene relicts, such as Rhagapodemus cf. frequens, and Pliopetaurista cf. pliocaenica, together with Early Pleistocene species is a remarkable feature of this site. This is also reflected in the environment which was still mainly forested but with spreading open areas and wetlands mainly in the form of water streams. The climate values show that the conditions were similar to the current ones but the comparison with the near and recent Monte La Mesa assemblage, dated to Early Biharian (beginning of the Calabrian Stage), and the appearance of several taxa related to open landscapes show that a cooling and arid trend in climate was already settled in the region during the Gelasian.