The palaeontological legacy of the Late Miocene Gargano’s Terre Rosse (southeastern Italy): evolutionary patterns, adaptive radiations, and unresolved origins

The Gargano region in the Apulian domain offers an exceptional fossil record that is rich in diversity and continuity, making it a key site for studying evolutionary processes on Mediterranean islands and palaeo-islands. This study provides an updated synthesis of the palaeontological data for the Gargano fauna, integrating the well-known mammalian records with those of the avifauna and herpetofauna. The fossil evidence highlights several modes of evolutionary change, including size variation in small mammals consistent with the “Island Rule”, adaptive radiations, and the emergence of new taxa through dispersal. Notably, the fauna of the Gargano islands reveals adaptive strategies that mirror the evolutionary processes of continental taxa, with the evolution of new morphological and ecological adaptations such as fossoriality in Mikrotia and malacophagy in Apulogalerix. Recent discoveries of the oldest fissure deposits in the region have significantly enhanced our understanding of the biochronological framework and shed new light on the origins of the Gargano fauna, contributing to ongoing debates about the genesis of these Miocene insular communities. Despite the remarkable richness of the fossil record, many aspects of the evolutionary history of this unique fauna remain unresolved, underscoring the fragmentary nature of the evidence and the challenges of reconstructing phylogenetic relationships based on incomplete records. This study aims to offer a comprehensive overview of the evolutionary history of the Gargano insular fauna, addressing complex and unresolved issues in the hopes of stimulating future research on this intricate palaeontological puzzle.