BMD values of tympanic bullae (g/cm2).

All measures refer to the left tympanic bullae. Left-to-right differences in shape, size and density were negligible in our experimental series.MMMTB = Mediterranean marine mammal tissue bank, University of Padova; Legnaro (PD), Italy; MSNM Ma = Museum of Natural History of Milan; Milan (Italy); MSNGe = Museum of Natural History “G. Doria” of Genova; Genova (Italy); UniPD = Collection of the Faculty of Veterinary Medicine of the University of Padova; Legnaro (PD), Italy.* = isolated bulla from specimen stranded in extra-national waters, body destroyed; private collector, Milan (Italy).