A key for Understanding Cisuralian Permian Tetrapod Ichnofaunas

The Gerola Valley site (Orobic Basin, Northern Italy): A key for understanding late Early Permian tetrapod ichnofaunas

Authors:

Marchetti et al

Abstract:

A taxonomic study has been carried out on the historical Gerola Valley locality (Pizzo del Diavolo formation, late Cisuralian), which represents one of the best tetrapod ichnosites of the whole Southern Alps (North Italy). With respect to previous studies, the ichnoassociation is now enlarged and lists the following taxa: Amphisauropus, Dromopus, Erpetopus, Hyloidichnus, Limnopus, Varanopus. The optimal preservation of the material, which in some cases shows even traces of the skin, allowed the recognition of a new morphotype of Varanopus. The invertebrate ichnoassociation is newly described and is representative of impoverished Scoyenia and Mermia ichnofacies. A detailed facies analysis of the uppermost arenitic-pelitic lithofacies of the Pizzo del Diavolo formation, which revealed the most abundant fossil content (Locality 1) and of two new localities (pelitic facies, Localities 2, 3) shows a transition from shallow lacustrine to floodplain and alluvial fan environments under a generally dry climate. Besides the taxonomic revision of vertebrate tracks, the final aims of our study are: i) the depositional, palaeoenvironmental and climatic reconstruction of this sector of the Orobic Basin through an integration of palaeontological data and facies analysis; and ii) the regional correlation of this key stratigraphic succession with other coeval ichnofaunas in Pangaea.