Convergent Evolution and Function of Hyperossification in Frogs

Meeting Abstract

40-4  Friday, Jan. 5 09:00 – 09:15  Convergent Evolution and Function of Hyperossification in Frogs PALUH, DJ*; STANLEY, EL; BLACKBURN, DC; Florida Museum of Natural History; Florida Museum of Natural History; Florida Museum of Natural History

Within fossil and extant anuran amphibians, a reoccurring trend in skull morphological diversity is hyperossification, i.e. the increased mineralization and excessive ossification of a skeletal element that results in dorsal sculpturing and pitted ornamentation of dermal bones. There is little research on the evolution of anuran skull hyperossification, but a preliminary survey of skeletal diversity has indicated that it has persisted or independently evolved in at least ten families of frogs in taxa ranging in size from 16 to 245 mm snout–vent length. Three disparate hypotheses exist on the function of hyperossification—water balance enhancement in arid environments, protection against predators during phragmotic behavior, and increased skull biomechanic capabilities related to feeding biology—but there have been no explicit tests whether there is an association between hyperossified skull shape and these different functions. We utilized high-resolution micro-computed tomography and 3-D geometric morphometric analysis to determine if there is a significant difference in shape between hyperossified and non-hyperossified skulls across all families of frogs. We then further tested if a predicted relationship exists between hyperossified skull shape, the habitation of arid environments, the use of phragmotic defensive behavior, and a carnivorous diet. Further, we conducted finite element analyses on a diversity of frogs to test if species that possess a hyperossified skull generally perform better at resisting high loads of stress, strain, and deformation compared to taxa that lack hyperossification, which would suggest higher protection against predators and higher bite forces and the ability to consume larger and harder prey.

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