Early Biharian amphibians and reptiles from Monte La Mesa (Verona, northeastern Italy): a typical herpetological assemblage from the Early Pleistocene of Veneto

A certain stability in the Quaternary herpetological assemblages of the Veneto area has been recognised in recent years, however further studies are needed in order to better comprehend their evolutionary dynamics. Amphibians and reptiles from the early-Biharian site of Monte La Mesa can prove useful in this respect as the assemblage is composed of taxa well known from other older and younger (Gelasian to Holocene) localities in Veneto as well as by providing some interesting exceptions. At least 11 taxa are recognised based on the fossil material studied: Ichthyosaura alpestris, Bombina sp., Bufo gr. B. bufo, cf. Bufotes gr. B. viridis, Ranidae indet., Testudines indet., Lacertidae indet. A, Lacertidae indet. B, Anguis gr. A. fragilis, Pseudopus cf. P. pannonicus, and Zamenis gr. Z. longissimus. The Monte La Mesa locality hosts the oldest occurrence of a green toad within the Quaternary of northern Italy, where the youngest preceding occurrence is in the Piacenzian strata of Piedmont. This suggests a possible disappearance and recolonization of the area by these bufonids only after the end of the Gelasian (unlike the pattern known for the Iberian Peninsula, where they disappeared in post-Jaramillo times). In addition to the latter, significant finds of non-Anguis anguine remains from the Monte La Mesa site support the presence of the P. pannonicus lineage in Italy during the Quaternary. Taken together, the palaeoherpetofauna supports the reconstruction of a humid and forested environment for the Monte La Mesa area during this interval of the Early Pleistocene.