Evolution of the specialized dentition of neotropical frugivore bats (Phyllostomidae: Stenodermatinae): a reassessment of dental morphology

Abstract Bats exhibit a wide variety of diets associated with craniodental modifications. Frugivory led to convergent dental specializations in flying foxes (Pteropodidae) and in the leaf-nosed bats (Phyllostomidae). While the mechanics of frugivory in Stenodermatinae are well studied, the characters involved in the evolutionary transition from their insectivorous ancestors remain unexplored. This study investigates the evolution of dental morphology in this clade by reconstructing character history and inferring its functional implications. We establish homologies between the derived dental structures of stenodermatine bats and the generalized dilambdodont molar pattern, clarifying the dental morphology of the subfamily. We analyzed 66 dental characters in 11 of the 19 genera of Stenodermatinae and five outgroup taxa, mapping them onto a molecular phylogeny using parsimony to assess synapomorphies. Consistency and retention indices indicate a high level of homoplasy consistent with adaptive plasticity, but also a strong phylogenetic signal, supporting the use of these characters for clade diagnosis. Key transformations for frugivory include reduced canine robustness, specialized premolars, and labial displacement of molar cusps. We also describe the evolution of accessory structures, including the mesoconule and its cristae, which increase occlusal complexity and are possibly related to diet and food processing. Cingula are interpreted as biomechanical reinforcements, while diastemata and occlusal gaps are analyzed as adaptations for fruit handling and the ejection of fibrous byproducts while chewing. This study demonstrates that the stenodermatine dentition evolved from an ancestral insectivorous pattern into a complex, derived toolkit, reflecting the adaptive history of one of the most successful bat radiations.