The ornamental design for a papertowelholder, as shown and described.
FIG. 1 is a front, top perspective view of a paper towel holder showing a first embodiment of our new design;
FIG. 2 is a front view thereof, the rear view being a mirror image of the front view;
FIG. 3 is a right side view thereof, the left side view being a mirror image of the right side view;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.
The features shown in broken lines are portions of the paper towel holder, namely, a top knob, surfaced ornamentation, and bottom details, forming no part of the claimed design. The features shown in long dash-short dash bolded broken lines indicate the bounds of the claimed design and otherwise form no part of the claimed design.