Characterization of paddlefish (Polyodon spathula) rostrum stellate bones

The electrosensory capabilities of the rostrum of the paddlefish (Polyodon spathula) were investigated previously. However, the structure–property relationship associated with the rostrum has yet to be explored. In this study, the stellate bone properties of the rostrum are examined as a function of spatial location on the rostrum using nanoindentation and Fourier transform infrared spectroscopy. Nanoindentation results indicated a constant elastic modulus along the middle section of the rostrum. However, the elastic modulus exhibited a gradient along the side of the rostrum, with the maximum modulus at the base of the rostrum. This study is part of an overall research project examining the electrosensory capabilities, hydrodynamics and structure–property relationships of the rostrum to develop new materials for force protection applications.