Humerus midshaft histology in a modern and fossil wombat

The common wombat (Vombatus ursinus) is equipped with a set of physiological and morphological adaptations suited to fossorial lifestyle. These allow wombats engage in efficient scratch-digging maintaining low basal metabolic rate while living underground. While bone microstructure has been described for several subterranean animals, histology received very little attention date. Here, we present preliminary insights into modern adult V. ursinus (Mt Fairy, New South Wales) Pleistocene fossil Vombatus sp. (Bakers Swamp, midshaft humeri. sample was well preserved, allowing us identify varying tissue types (woven, parallel-fibred, lamellar). showed vascularity composed primary secondary osteons, simple longitudinal radial vessels. We also observed evidence Haversian remodelling (i.e. localised replacement pre-existing bone) coarse compact cancellous within the inner cortex diaphysis. poorly but likely matrix organisation similar specimen. use these data discuss hypotheses forelimb biomechanical microscopic adaptation burrow environment. encourage future intraskeletal examination populations better inform their ecological behaviour palaeontological contexts.