The ornamental design for a posterhangingrod, as shown and described.
FIG. 1 is a perspective view of a poster hanging rod, showing my new design, with a poster and two rod supports shown in broken lines, the broken line portions forming no part of the claimed design;
FIG. 2 is a left side view thereof, the right side being a mirror image thereof;
FIG. 3 is a front view thereof, the rear view being a mirror image thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a perspective view of a second embodiment of the invention, the areas between the broken away lines in the second embodiment forming no part of the claimed design;
FIG. 7 is a left side view thereof, the right side being a mirror image thereof;
FIG. 8 is a front view thereof, the rear view being a mirror image thereof;