  We report the evolution of the Raman active A_g phonon modes in the
charge-ordered manganite Pr_{0.63}Ca_{0.37}MnO_{3} as a function of temperature
from 300K to 25K. Our studies reveal that the linewidths of A_g(2) and A_g(4)
phonons increase as temperature decreases. This anomalous temperature
dependence of phonon lineshapes, seen for the first time in charge ordered
manganites, can be quantitatively understood in terms of strong spin-phonon
coupling involving t_{2g} spins and A_g phonons.
