Megamouth shark
The shark has around fifty rows of very small teeth on each jaw, but only three rows are usable. Females seem to have fewer teeth rows than males. The upper and lower jaws have a symphyseal (where the two halves of the jaw meet) toothless space, but it is larger in the upper jaw. A difference between the upper and lower teeth was recognized on a female specimen: the first five upper teeth are smaller than the first five lower teeth.