Fig. 2: Microtubules in the enameloid layer of the Port Jackson shark teeth.
From: Shape-preserving erosion controlled by the graded microarchitecture of shark tooth enameloid
a Dark-field optical micrograph of a sagittal section, and b bright-field optical micrograph of a transverse section of the cusp (rows 6–7) showing the paths of tubules from the inner toward the outer enameloid at the free surface of the cusp. c SEM micrographs, showing that the arced morphologies of microtubules result in their being cross- vs. longitudinally sectioned in the inner vs. outer enameloid, respectively (arrows).
